Impact: cleanup, no code changed
Remove an ugly #ifdef CONFIG_SMP from panic(), by providing
an smp_send_stop() wrapper on UP too.
LKML-Reference: <49B91A7E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: eliminate secondary warnings during panic()
We can panic() in a number of difficult, atomic contexts, hence
we use bust_spinlocks(1) in panic() to increase oops_in_progress,
which prevents various debug checks we have in place.
But in practice this protection only covers the first few printk's
done by panic() - it does not cover the later attempt to stop all
other CPUs and kexec(). If a secondary warning triggers in one of
those facilities that can make the panic message scroll off.
So do bust_spinlocks(0) only much later in panic(). (which code
is only reached if panic policy is relaxed that it can return
after a warning message)
Reported-by: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49B91A7E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Do not output smp-call related warnings in the oops/panic codepath.
Reported-by: Jan Beulich <jbeulich@novell.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <49B91A7E.76E4.0078.0@novell.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix double unlock crash
Thomas Gleixner noticed that the simplified double_unlock_hb()
became ... too unsophisticated: in the hb1 == hb2 case it will
do a double unlock.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Darren Hart <dvhltc@us.ibm.com>
LKML-Reference: <20090312221118.11146.68610.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Do __ftrace_replace_code for !FTRACE_FL_CONVERTED rec will always
fail, we should ignore this rec.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: "Steven Rostedt ;" <rostedt@goodmis.org>
LKML-Reference: <49BA2472.4060206@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
If dyn_ftrace is freed before ftrace_release(), ftrace_release()
will free it again and make ftrace_free_records wrong.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Cc: "Steven Rostedt ;" <rostedt@goodmis.org>
LKML-Reference: <49BA23D9.1050900@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Provide basic callbacks to do syscall tracing.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
LKML-Reference: <1236401580-5758-2-git-send-email-fweisbec@gmail.com>
[ simplified it to a trace_printk() for now. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
It is redundant to have 'SOFTIRQ' in the softirq names.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The binary_buffers directory in /debugfs/tracing held the files
to read the trace buffers in a binary format. This held one file
per CPU buffer. But we also have a per_cpu directory that holds
a way to read the pretty-print formats.
This patch moves the binary buffers into the per_cpu_directory:
# ls /debug/tracing/per_cpu/cpu1/
trace trace_pipe trace_pipe_raw
The new name is called "trace_pipe_raw". The binary buffers always
acted similar to trace_pipe, except that they produce raw data.
Requested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
This is presumably what those definitions are for, and while all archs
define cpu_core_map/cpu_sibling map, that's changing (eg. x86 wants to
change it to a pointer).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Impact: documentation
The use of the double __builtin_contant_p checks in the event_trace_printk
can be confusing to developers and reviewers. This patch adds a comment
to explain why it is there.
Requested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
LKML-Reference: <20090313122235.43EB.A69D9226@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
In a private email conversation I explained how the ring buffer
page worked by using silly ASCII art. Ingo suggested that I add
that to the comments of the code.
Here it is.
Requested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Unlike TRACE_FORMAT() macros, the TRACE_EVENT() macros do not show
the event name in the trace file. Knowing the event type in the trace
output is very useful.
Instead of:
task swapper:0 [140] ==> ntpd:3308 [120]
We now have:
sched_switch: task swapper:0 [140] ==> ntpd:3308 [120]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
commit c3ffc7a40b
"Don't use tracing_record_cmdline() in workqueue tracer"
has a race window.
find_task_by_vpid() requires task_list_lock().
LKML-Reference: <20090313090042.43CD.A69D9226@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Introduce softirq entry/exit tracepoints. These are useful for
augmenting existing tracers, and to figure out softirq frequencies and
timings.
[
s/irq_softirq_/softirq_/ for trace point names and
Fixed printf format in TRACE_FORMAT macro
- Steven Rostedt
]
LKML-Reference: <20090312183603.GC3352@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Create a 'softirq_to_name' array, which is indexed by softirq #, so
that we can easily convert between the softirq index # and its name, in
order to get more meaningful output messages.
LKML-Reference: <20090312183336.GB3352@redhat.com>
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If the stack tracing is disabled (by default) the stack_trace file
will only contain the header:
# cat /debug/tracing/stack_trace
Depth Size Location (0 entries)
----- ---- --------
This can be frustrating to a developer that does not realize that the
stack tracer is disabled. This patch adds the following text:
# cat /debug/tracing/stack_trace
Depth Size Location (0 entries)
----- ---- --------
#
# Stack tracer disabled
#
# To enable the stack tracer, either add 'stacktrace' to the
# kernel command line
# or 'echo 1 > /proc/sys/kernel/stack_tracer_enabled'
#
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The binary printk saves a pointer to the format string in the ring buffer.
On output, the format is processed. But if the user is reading the
ring buffer through a binary interface, the pointer is meaningless.
This patch creates a file called printk_formats that maps the pointers
to the formats.
# cat /debug/tracing/printk_formats
0xffffffff80713d40 : "irq_handler_entry: irq=%d handler=%s\n"
0xffffffff80713d48 : "lock_acquire: %s%s%s\n"
0xffffffff80713d50 : "lock_release: %s\n"
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: speed up on event tracing
The event_trace_printk is currently a wrapper function that calls
trace_vprintk. Because it uses a variable for the fmt it misses out
on the optimization of using the binary printk.
This patch makes event_trace_printk into a macro wrapper to use the
fmt as the same as the trace_printks.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix callsites with dynamic format strings
Since its new binary implementation, trace_printk() internally uses static
containers for the format strings on each callsites. But the value is
assigned once at build time, which means that it can't take dynamic
formats.
So this patch unearthes the raw trace_printk implementation for the callers
that will need trace_printk to be able to carry these dynamic format
strings. The trace_printk() macro will use the appropriate implementation
for each callsite. Most of the time however, the binary implementation will
still be used.
The other impact of this patch is that mmiotrace_printk() will use the old
implementation because it calls the low level trace_vprintk and we can't
guess here whether the format passed in it is dynamic or not.
Some parts of this patch have been written by Steven Rostedt (most notably
the part that chooses the appropriate implementation for each callsites).
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: do not confuse user on small trace buffer sizes
When the system boots up, the trace buffer is small to conserve memory.
It is only two pages per online CPU. When the tracer is used, it expands
to the default value.
This can confuse the user if they look at the buffer size and see only
7, but then later they see 1408.
# cat /debug/tracing/buffer_size_kb
7
# echo sched_switch > /debug/tracing/current_tracer
# cat /debug/tracing/buffer_size_kb
1408
This patch tries to help remove this confustion by showing that the
buffer has not been expanded.
# cat /debug/tracing/buffer_size_kb
7 (expanded: 1408)
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: speed up and remove possible races
The get_online_cpus was added to the ring buffer because the original
design would free the ring buffer on a CPU that was being taken
off line. The final design kept the ring buffer around even when the
CPU was taken off line. This is to allow a user to still read the
information on that ring buffer.
Most of the get_online_cpus are no longer needed since the ring buffer will
not disappear from the use cases.
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The hotplug code in the ring buffers is for use with CPU hotplug,
not generic hotplug.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: prevent races with ring_buffer_expanded
This patch places the expanding of the tracing buffer under the
protection of the trace_types_lock mutex. It is highly unlikely
that there would be any contention, but better safe than sorry.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
Some of the comments about the trace buffer resizing is gobbledygook.
And I wonder why people question if I'm a native English speaker.
This patch makes the comments make a bit more sense.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
The naming clashes with upcoming softirq tracepoints, so rename the
APIs to lockdep_*().
Requested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: simplify code
I mistakenly included the pointer value ordering in the
double_unlock_hb() in my previous patch. It's only necessary
in the double_lock_hb() function. This patch removes it.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312221118.11146.68610.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Export the setup_irq() and remove_irq() symbols.
I'd like to export these functions since I have timer
code that needs to use setup_irq() early on (too early
for request_irq()), and the same code can also be
compiled as a module.
Signed-off-by: Magnus Damm <damm@igel.co.jp>
LKML-Reference: <20090312120559.2926.82371.sendpatchset@rx1.opensource.se>
[ changed to _GPL as these are special APIs deep inside the irq layer. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Modify remove_irq() to match setup_irq().
Signed-off-by: Magnus Damm <damm@igel.co.jp>
LKML-Reference: <20090312120551.2926.43942.sendpatchset@rx1.opensource.se>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add new API
This patch adds a remove_irq() function for releasing
interrupts requested with setup_irq().
Without this patch we have no way of releasing such
interrupts since free_irq() today tries to kfree()
the irqaction passed with setup_irq().
Signed-off-by: Magnus Damm <damm@igel.co.jp>
LKML-Reference: <20090312120542.2926.56609.sendpatchset@rx1.opensource.se>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Older versions of the futex code held the mmap_sem which had to
be dropped in order to call get_user(), so a two-pronged fault
handling mechanism was employed to handle faults of the atomic
operations. The mmap_sem is no longer held, so get_user()
should be adequate. This patch greatly simplifies the logic and
improves legibility.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075612.9856.48612.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: rt-mutex failure case fix
futex_lock_pi can potentially return -EFAULT with the rt_mutex
held. This seems like the wrong thing to do as userspace should
assume -EFAULT means the lock was not taken. Even if it could
figure this out, we'd be leaving the pi_state->owner in an
inconsistent state. This patch unlocks the rt_mutex prior to
returning -EFAULT to userspace.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075606.9856.88729.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
RT tasks should set their timer slack to 0 on their own. This
patch removes the 'if (rt_task()) slack = 0;' block in
futex_wait.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Arjan van de Ven <arjan@linux.intel.com>
LKML-Reference: <20090312075559.9856.28822.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
The futex code uses double_lock_hb() which locks the hb->lock's
in pointer value order. There is no parallel unlock routine,
and the code unlocks them in name order, ignoring pointer value.
This patch adds double_unlock_hb() to refactor the duplicated
code segments.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075552.9856.48021.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix races
futex_requeue and futex_lock_pi still had some bad
(get|put)_futex_key() usage. This patch adds the missing
put_futex_keys() and corrects a goto in futex_lock_pi() to avoid
a double get.
Build and boot tested on a 4 way Intel x86_64 workstation.
Passes basic pthread_mutex and PI tests out of
ltp/testcases/realtime.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075545.9856.75152.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
The futex_hash_bucket can be a bit confusing when first looking
at the code as it is a shared queue (and futex_q isn't a queue
at all, but rather an element on the queue).
The mmap_sem is no longer held outside of the
futex_handle_fault() routine, yet numerous comments refer to it.
The fshared argument is no an integer. I left some of these
comments along as they are simply removed in future patches.
Some of the commentary refering to futexes by virtual page
mappings was not very clear, and completely accurate (as for
shared futexes both the page and the offset are used to
determine the key). For the purposes of the function
description, just referring to "the futex" seems sufficient.
With hashed futexes we now access the page after the hash-bucket
is locked, and not only after it is enqueued.
Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <20090312075537.9856.29954.stgit@Aeon>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: save on memory
Currently, a ring buffer was allocated for each "possible_cpus". On
some systems, this is the same as NR_CPUS. Thus, if a system defined
NR_CPUS = 64 but it only had 1 CPU, we could have possibly 63 useless
ring buffers taking up space. With a default buffer of 3 megs, this
could be quite drastic.
This patch changes the ring buffer code to only allocate ring buffers
for online CPUs. If a CPU goes off line, we do not free the buffer.
This is because the user may still have trace data in that buffer
that they would like to look at.
Perhaps in the future we could add code to delete a ring buffer if
the CPU is offline and the ring buffer becomes empty.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to task live locking on reading trace_pipe on one CPU
The same code is used for both trace_pipe (all CPUS) and the per_cpu
trace_pipe file. When there is no data to read, it will check for
signals and wait on the trace wait queue.
The problem happens with the per_cpu wait. The trace_wait code checks
all CPUs. Thus, if there's data in another CPU buffer, then it will
exit the wait, without checking for signals or waiting on the wait queue.
It would then try to read the empty buffer, and since that will just
return nothing, then it will try to wait again. Unfortunately, that will
again fail due to there still being data in the other buffers. This
ends up with a live lock for the task.
This patch fixes the trace_wait to be aware that the iterator may only
be waiting on a single buffer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
To save memory, the tracer ring buffers are set to a minimum.
The activating of a trace expands the ring buffer size. This patch
adds this expanding, when an event is activated.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: less memory impact on systems not using tracer
When the kernel boots up that has tracing configured, it allocates
the default size of the ring buffer. This currently happens to be
1.4Megs per possible CPU. This is quite a bit of wasted memory if
the system is never using the tracer.
The current solution is to keep the ring buffers to a minimum size
until the user uses them. Once a tracer is piped into the current_tracer
the ring buffer will be expanded to the default size. If the user
changes the size of the ring buffer, it will take the size given
by the user immediately.
If the user adds a "ftrace=" to the kernel command line, then the ring
buffers will be set to the default size on initialization.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: more precise avg_overlap metric - better load-balancing
avg_overlap is used to measure the runtime overlap of the waker and
wakee.
However, when a process changes behaviour, eg a pipe becomes
un-congested and we don't need to go to sleep after a wakeup
for a while, the avg_overlap value grows stale.
When running we use the avg runtime between preemption as a
measure for avg_overlap since the amount of runtime can be
correlated to cache footprint.
The longer we run, the less likely we'll be wanting to be
migrated to another CPU.
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236709131.25234.576.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We were returning early in the sysfs directory cleanup function if the
user belonged to a non init usernamespace. Due to this a lot of the
cleanup was not done and we were left with a leak. Fix the leak.
Reported-by: Serge Hallyn <serue@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: prevent locking up by lockdep tracer
The lockdep tracer uses trace_vprintk and thus trace_vprintk can not
call back into lockdep without locking up.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Using the function_graph tracer in recent kernels generates a spew of
preemption BUGs. Fix this by not requiring trace_clock_local() users
to disable preemption themselves.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
There existed a lot of <space><tab>'s in the tracing code. This
patch removes them.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up / comments
The comments that described the ftrace macros to manipulate the
TRACE_EVENT and TRACE_FORMAT macros no longer match the code.
This patch updates them.
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
In trying to stay consistant with the C style format in the TRACE_EVENT
macro, it makes more sense to do the printk after the assigning of
the variables.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The event directory files type and available_types were no longer
needed with the new TRACE_EVENT_FORMAT macros, they were deleted.
But by accident the available_events file was also removed.
This patch brings it back.
Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: micro-optimization
We can avoid the sched domain walk on try_to_wake_up() when we know
there are no groups.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236603381.8389.455.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix to prevent crash on calling NULL function pointer
The ftrace internal records have their format exported via the event
system under the ftrace subsystem. These are only for exporting the
format to allow binary readers to be able to parse them in a binary
output.
The ftrace subsystem events can only be enabled via the ftrace tracers
and do not have a registering function. The event files expect the
event record to have registering function and will call it directly.
Passing in a ftrace subsystem event will cause the kernel to crash
because it will execute a NULL pointer.
This patch prevents the ftrace subsystem from being viewable to the
event enabling files.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The offsetof and sizeof are of type size_t, and instead of typecasting
them to unsigned int for printk formatting, one could just use %zu.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
Obviously, this goto is useless. Remove it.
Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Roland McGrath <roland@redhat.com>
LKML-Reference: <20090310093447.GC3179@hack>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
"for (++cpu ; cpu < num_possible_cpus(); cpu++)" statement assumes
possible cpus have continuous number - but that's a wrong assumption.
Insted, cpumask_next() should be used.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090310104437.A480.A69D9226@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
The TRACE_EVENT_FORMAT macro is no longer used by trace points
and only the DECLARE_TRACE, TRACE_FORMAT or TRACE_EVENT macros should
be used by them. Although the TRACE_EVENT_FORMAT macro is still used
by the internal tracing utility, it should not be used in core
kernel code.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up and enhancement
The TRACE_EVENT_FORMAT macro looks quite ugly and is limited in its
ability to save data as well as to print the record out. Working with
Ingo Molnar, we came up with a new format that is much more pleasing to
the eye of C developers. This new macro is more C style than the old
macro, and is more obvious to what it does.
Here's the example. The only updated macro in this patch is the
sched_switch trace point.
The old method looked like this:
TRACE_EVENT_FORMAT(sched_switch,
TP_PROTO(struct rq *rq, struct task_struct *prev,
struct task_struct *next),
TP_ARGS(rq, prev, next),
TP_FMT("task %s:%d ==> %s:%d",
prev->comm, prev->pid, next->comm, next->pid),
TRACE_STRUCT(
TRACE_FIELD(pid_t, prev_pid, prev->pid)
TRACE_FIELD(int, prev_prio, prev->prio)
TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
next_comm,
TP_CMD(memcpy(TRACE_ENTRY->next_comm,
next->comm,
TASK_COMM_LEN)))
TRACE_FIELD(pid_t, next_pid, next->pid)
TRACE_FIELD(int, next_prio, next->prio)
),
TP_RAW_FMT("prev %d:%d ==> next %s:%d:%d")
);
The above method is hard to read and requires two format fields.
The new method:
/*
* Tracepoint for task switches, performed by the scheduler:
*
* (NOTE: the 'rq' argument is not used by generic trace events,
* but used by the latency tracer plugin. )
*/
TRACE_EVENT(sched_switch,
TP_PROTO(struct rq *rq, struct task_struct *prev,
struct task_struct *next),
TP_ARGS(rq, prev, next),
TP_STRUCT__entry(
__array( char, prev_comm, TASK_COMM_LEN )
__field( pid_t, prev_pid )
__field( int, prev_prio )
__array( char, next_comm, TASK_COMM_LEN )
__field( pid_t, next_pid )
__field( int, next_prio )
),
TP_printk("task %s:%d [%d] ==> %s:%d [%d]",
__entry->prev_comm, __entry->prev_pid, __entry->prev_prio,
__entry->next_comm, __entry->next_pid, __entry->next_prio),
TP_fast_assign(
memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN);
__entry->prev_pid = prev->pid;
__entry->prev_prio = prev->prio;
memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN);
__entry->next_pid = next->pid;
__entry->next_prio = next->prio;
)
);
This macro is called TRACE_EVENT, it is broken up into 5 parts:
TP_PROTO: the proto type of the trace point
TP_ARGS: the arguments of the trace point
TP_STRUCT_entry: the structure layout of the entry in the ring buffer
TP_printk: the printk format
TP_fast_assign: the method used to write the entry into the ring buffer
The structure is the definition of how the event will be saved in the
ring buffer. The printk is used by the internal tracing in case of
an oops, and the kernel needs to print out the format of the record
to the console. This the TP_printk gives a means to show the records
in a human readable format. It is also used to print out the data
from the trace file.
The TP_fast_assign is executed directly. It is basically like a C function,
where the __entry is the handle to the record.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
This removes the custom made STR(x) macros in the tracer and uses
the generic __stringify macro instead.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The macros TPPROTO, TPARGS, TPFMT, TPRAWFMT, and TPCMD all look a bit
ugly. This patch adds an underscore to their names.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix compiler warnings
On x86_64 sizeof and offsetof are treated as long, where as on x86_32
they are int. This patch typecasts them to unsigned int to avoid
one arch giving warnings while the other does not.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
CLONE_PARENT can fool the ->self_exec_id/parent_exec_id logic. If we
re-use the old parent, we must also re-use ->parent_exec_id to make
sure exit_notify() sees the right ->xxx_exec_id's when the CLONE_PARENT'ed
task exits.
Also, move down the "p->parent_exec_id = p->self_exec_id" thing, to place
two different cases together.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Serge E. Hallyn <serge@hallyn.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Frans Pop reported the crash below when running an s390 kernel under Hercules:
Kernel BUG at 000738b4 verbose debug info unavailable!
fixpoint divide exception: 0009 #1! SMP
Modules linked in: nfs lockd nfs_acl sunrpc ctcm fsm tape_34xx
cu3088 tape ccwgroup tape_class ext3 jbd mbcache dm_mirror dm_log dm_snapshot
dm_mod dasd_eckd_mod dasd_mod
CPU: 0 Not tainted 2.6.27.19 #13
Process awk (pid: 2069, task: 0f9ed9b8, ksp: 0f4f7d18)
Krnl PSW : 070c1000 800738b4 (acct_update_integrals+0x4c/0x118)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:1 PM:0
Krnl GPRS: 00000000 000007d0 7fffffff fffff830
00000000 ffffffff 00000002 0f9ed9b8
00000000 00008ca0 00000000 0f9ed9b8
0f9edda4 8007386e 0f4f7ec8 0f4f7e98
Krnl Code: 800738aa: a71807d0 lhi %r1,2000
800738ae: 8c200001 srdl %r2,1
800738b2: 1d21 dr %r2,%r1
>800738b4: 5810d10e l %r1,270(%r13)
800738b8: 1823 lr %r2,%r3
800738ba: 4130f060 la %r3,96(%r15)
800738be: 0de1 basr %r14,%r1
800738c0: 5800f060 l %r0,96(%r15)
Call Trace:
( <000000000004fdea>! blocking_notifier_call_chain+0x1e/0x2c)
<0000000000038502>! do_exit+0x106/0x7c0
<0000000000038c36>! do_group_exit+0x7a/0xb4
<0000000000038c8e>! SyS_exit_group+0x1e/0x30
<0000000000021c28>! sysc_do_restart+0x12/0x16
<0000000077e7e924>! 0x77e7e924
Reason for this is that cpu time accounting usually only happens from
interrupt context, but acct_update_integrals gets also called from
process context with interrupts enabled.
So in acct_update_integrals we may end up with the following scenario:
Between reading tsk->stime/tsk->utime and tsk->acct_timexpd an interrupt
happens which updates accouting values. This causes acct_timexpd to be
greater than the former stime + utime. The subsequent calculation of
dtime = cputime_sub(time, tsk->acct_timexpd);
will be negative and the division performed by
cputime_to_jiffies(dtime)
will generate an exception since the result won't fit into a 32 bit
register.
In order to fix this just always disable interrupts while accessing any
of the accounting values.
Reported by: Frans Pop <elendil@planet.nl>
Tested by: Frans Pop <elendil@planet.nl>
Cc: stable@kernel.org
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: improve workqueue tracer output
Currently, /sys/kernel/debug/tracing/trace_stat/workqueues can display
wrong and strange thread names.
Why?
Currently, ftrace has tracing_record_cmdline()/trace_find_cmdline()
convenience function that implements a task->comm string cache.
This can avoid unnecessary memcpy overhead and the workqueue tracer
uses it.
However, in general, any trace statistics feature shouldn't use
tracing_record_cmdline() because trace statistics can display
very old process. Then comm cache can return wrong string because
recent process overrides the cache.
Fortunately, workqueue trace guarantees that displayed processes
are live. Thus we can search comm string from PID at display time.
<before>
% cat workqueues
# CPU INSERTED EXECUTED NAME
# | | | |
7 431913 431913 kondemand/7
7 0 0 tail
7 21 21 git
7 0 0 ls
7 9 9 cat
7 832632 832632 unix_chkpwd
7 236292 236292 ls
Note: tail, git, ls, cat unix_chkpwd are obiously not workqueue thread.
<after>
% cat workqueues
# CPU INSERTED EXECUTED NAME
# | | | |
7 510 510 kondemand/7
7 0 0 kmpathd/7
7 15 15 ata/7
7 0 0 aio/7
7 11 11 kblockd/7
7 1063 1063 work_on_cpu/7
7 167 167 events/7
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Remove a few leftovers and clean up the code a bit.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: faster and lighter tracing
Now that we have trace_bprintk() which is faster and consume lesser
memory than trace_printk() and has the same purpose, we can now drop
the old implementation in favour of the binary one from trace_bprintk(),
which means we move all the implementation of trace_bprintk() to
trace_printk(), so the Api doesn't change except that we must now use
trace_seq_bprintk() to print the TRACE_PRINT entries.
Some changes result of this:
- Previously, trace_bprintk depended of a single tracer and couldn't
work without. This tracer has been dropped and the whole implementation
of trace_printk() (like the module formats management) is now integrated
in the tracing core (comes with CONFIG_TRACING), though we keep the file
trace_printk (previously trace_bprintk.c) where we can find the module
management. Thus we don't overflow trace.c
- changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries.
- change a bit trace_printk/trace_vprintk macros to support non-builtin formats
constants, and fix 'const' qualifiers warnings. But this is all transparent for
developers.
- etc...
V2:
- Rebase against last changes
- Fix mispell on the changelog
V3:
- Rebase against last changes (moving trace_printk() to kernel.h)
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add a generic printk() for tracing, like trace_printk()
trace_bprintk() uses the infrastructure to record events on ring_buffer.
[ fweisbec@gmail.com: ported to latest -tip, made it work if
!CONFIG_MODULES, never free the format strings from modules
because we can't keep track of them and conditionnaly create
the ftrace format strings section (reported by Steven Rostedt) ]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-4-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: save on memory for tracing
Current tracers are typically using a struct(like struct ftrace_entry,
struct ctx_switch_entry, struct special_entr etc...)to record a binary
event. These structs can only record a their own kind of events.
A new kind of tracer need a new struct and a lot of code too handle it.
So we need a generic binary record for events. This infrastructure
is for this purpose.
[fweisbec@gmail.com: rebase against latest -tip, make it safe while sched
tracing as reported by Steven Rostedt]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <1236356510-8381-3-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Use the mutual exclusion provided by the text edit lock in the kprobes code. It
allows coherent manipulation of the kernel code by other subsystems.
Changelog:
Move the kernel_text_lock/unlock out of the for loops.
Use text_mutex directly instead of a function.
Remove whitespace modifications.
(note : kprobes_mutex is always taken outside of text_mutex)
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <49B14306.2080202@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Use test_tsk_need_resched(), set_tsk_need_resched(), need_resched()
instead of using TIF_NEED_RESCHED.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <49B10BA4.9070209@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix deadlock while using set_ftrace_pid
Reproducer:
# cd /sys/kernel/debug/tracing
# echo $$ > set_ftrace_pid
then, console becomes hung.
Details:
when writing set_ftracepid, kernel callstack is following
ftrace_pid_write()
mutex_lock(&ftrace_lock);
ftrace_update_pid_func()
mutex_lock(&ftrace_lock);
mutex_unlock(&ftrace_lock);
mutex_unlock(&ftrace_lock);
then, system always deadlocks when ftrace_pid_write() is called.
In past days, ftrace_pid_write() used ftrace_start_lock, but
commit e6ea44e9b4 consolidated
ftrace_start_lock to ftrace_lock.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <srostedt@redhat.com>
LKML-Reference: <20090306151155.0778.A69D9226@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add reserved allocation functionality and use it for module
percpu variables
This patch implements reserved allocation from the first chunk. When
setting up the first chunk, arch can ask to set aside certain number
of bytes right after the core static area which is available only
through a separate reserved allocator. This will be used primarily
for module static percpu variables on architectures with limited
relocation range to ensure that the module perpcu symbols are inside
the relocatable range.
If reserved area is requested, the first chunk becomes reserved and
isn't available for regular allocation. If the first chunk also
includes piggy-back dynamic allocation area, a separate chunk mapping
the same region is created to serve dynamic allocation. The first one
is called static first chunk and the second dynamic first chunk.
Although they share the page map, their different area map
initializations guarantee they serve disjoint areas according to their
purposes.
If arch doesn't setup reserved area, reserved allocation is handled
like any other allocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Impact: allow user apps to read binary format of basic ftrace entries
Currently, only defined raw events export their formats so a binary
reader can parse them. There's no reason that the default ftrace entries
can't export their formats.
This patch adds a subsystem called "ftrace" in the events directory
that includes the ftrace entries for basic ftrace recorded items.
These only have three files in the events directory:
type : printf
available_types : printf
format : format for the event entry
For example:
# cat /debug/tracing/events/ftrace/wakeup/format
name: wakeup
ID: 3
format:
field:unsigned char type; offset:0; size:1;
field:unsigned char flags; offset:1; size:1;
field:unsigned char preempt_count; offset:2; size:1;
field:int pid; offset:4; size:4;
field:int tgid; offset:8; size:4;
field:unsigned int prev_pid; offset:12; size:4;
field:unsigned char prev_prio; offset:16; size:1;
field:unsigned char prev_state; offset:17; size:1;
field:unsigned int next_pid; offset:20; size:4;
field:unsigned char next_prio; offset:24; size:1;
field:unsigned char next_state; offset:25; size:1;
field:unsigned int next_cpu; offset:28; size:4;
print fmt: "%u:%u:%u ==+ %u:%u:%u [%03u]"
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
Move the macro that creates the event format file to a separate header.
This will allow the default ftrace events to use this same macro
to create the formats to read those events.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
All file_operations structures should be constant. No one is going to
change them.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Clean up menu structure, introduce TRACING_SUPPORT switch that signals
whether an architecture supports various instrumentation mechanisms.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix function graph trace hang / drop pointless softirq on UP
While debugging a function graph trace hang on an old PII, I saw
that it consumed most of its time on the timer interrupt. And
the domain rebalancing softirq was the most concerned.
The timer interrupt calls trigger_load_balance() which will
decide if it is worth to schedule a rebalancing softirq.
In case of builtin UP kernel, no problem arises because there is
no domain question.
In case of builtin SMP kernel running on an SMP box, still no
problem, the softirq will be raised each time we reach the
next_balance time.
In case of builtin SMP kernel running on a UP box (most distros
provide default SMP kernels, whatever the box you have), then
the CPU is attached to the NULL sched domain. So a kind of
unexpected behaviour happen:
trigger_load_balance() -> raises the rebalancing softirq later
on softirq: run_rebalance_domains() -> rebalance_domains() where
the for_each_domain(cpu, sd) is not taken because of the NULL
domain we are attached at. Which means rq->next_balance is never
updated. So on the next timer tick, we will enter
trigger_load_balance() which will always reschedule() the
rebalacing softirq:
if (time_after_eq(jiffies, rq->next_balance))
raise_softirq(SCHED_SOFTIRQ);
So for each tick, we process this pointless softirq.
This patch fixes it by checking if we are attached to the null
domain before raising the softirq, another possible fix would be
to set the maximal possible JIFFIES value to rq->next_balance if
we are attached to the NULL domain.
v2: build fix on UP
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <49af242d.1c07d00a.32d5.ffffc019@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: decrease hangs risks with the graph tracer on slow systems
Since the function graph tracer can spend too much time on timer
interrupts, it's better now to use the more lightweight local
clock. Anyway, the function graph traces are more reliable on a
per cpu trace.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <49af243d.06e9300a.53ad.ffff840c@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
The atomic debug modifiers are already defined in
kernel/lockdep_internals.h.
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <alpine.DEB.2.00.0903050222160.30401@chino.kir.corp.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Use a more generic name - this also allows the prototype to move
to kernel.h and be generally available to kernel developers who
want to do some quick tracing.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The latency tracers (irqsoff, preemptoff, preemptirqsoff, and wakeup)
are pretty useless with the default output format. This patch makes them
automatically enable the latency format when they are selected. They
also record the state of the latency option, and if it was not enabled
when selected, they disable it on reset.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
Both print_lat_fmt and print_trace_fmt do pretty much the same thing
except for one different function call. This patch consolidates the
two functions and adds an if statement to perform the difference.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The trace and latency_trace function pointers are identical for
every tracer but the function tracer. The differences in the function
tracer are trivial (latency output puts paranthesis around parent).
This patch removes the latency_trace pointer and all prints will
now just use the trace output function pointer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
With the removal of the latency_trace file, we lost the ability
to see some of the finer details in a trace. Like the state of
interrupts enabled, the preempt count, need resched, and if we
are in an interrupt handler, softirq handler or not.
This patch simply creates an option to bring back the old format.
This also removes the warning about an unused variable that held
the latency_trace file operations.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The buffer used by trace_seq was updated incorrectly. Instead
of consuming what was actually read, it consumed the rest of the
buffer on reads.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix trace read to conform to standards
Andrew Morton, Theodore Tso and H. Peter Anvin brought to my attention
that a userspace read should not return -EFAULT if it succeeded in
copying anything. It should only return -EFAULT if it failed to copy
at all.
This patch modifies the check of copy_from_user and updates the return
code appropriately.
I also used H. Peter Anvin's short cut rule to just test ret == count.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If a partial ring_buffer_page_read happens, then some of the
incremental timestamps may be lost. This patch writes the
recent timestamp into the page that is passed back to the caller.
A partial ring_buffer_page_read is where the full page would not
be written back to the user, and instead, just part of the page
is copied to the user. A full page would be a page swap with the
ring buffer and the timestamps would be correct.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to ftrace_dump output corruption
The commit: b04cc6b1f6
tracing/core: introduce per cpu tracing files
added a new field to the iterator called cpu_file. This was a handle
to differentiate between the per cpu trace output files and the
all cpu "trace" file. The all cpu "trace" file required setting this
to TRACE_PIPE_ALL_CPU.
The problem is that the ftrace_dump sets up its own iterator but was
not updated to handle this change. The result was only CPU 0 printing
out on crash and a lot of "<0>"'s also being printed.
Reported-by: Thomas Gleixner <tglx@linuxtronix.de>
Tested-by: Darren Hart <dvhtc@us.ibm.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If a machine is flooded by network frames, a cpu can loop
100% of its time inside ksoftirqd() without calling schedule().
This can delay RCU grace period to insane values.
Adding rcu_qsctr_inc() call in ksoftirqd() solves this problem.
Paul: "This regression was a result of the recent change from
"schedule()" to "cond_resched()", which got rid of that quiescent
state in the common case where a reschedule is not needed".
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clarify lockdep printk text
print_irq_inversion_bug() gets handed state strings of the form
"HARDIRQ", "SOFTIRQ", "RECLAIM_FS"
and appends "-irq-{un,}safe" to them, which is either redudant for *IRQ or
confusing in the RECLAIM_FS case.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236175192.5330.7585.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
In the recent mark_lock_irq() rework a bug snuck in that would report the
state of write locks causing irq inversion under a read lock as a read
lock.
Fix this by masking the read bit of the state when validating write
dependencies.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1236172646.5330.7450.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new feature
This patch creates a directory of files that correspond to the
per CPU ring buffers. These are binary files and are made to
be used with splice. This is the fastest way to extract data from
the ftrace ring buffers.
Thanks to Jiaying Zhang for pushing me to get this code fixed,
and to Eduard - Gabriel Munteanu for his splice code that helped
me debug my code.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: dont leave holes in read buffer page
The ring_buffer_read_page swaps a given page with the reader page
of the ring buffer, if certain conditions are set:
1) requested length is big enough to hold entire page data
2) a writer is not currently on the page
3) the page is not partially consumed.
Instead of swapping with the supplied page. It copies the data to
the supplied page instead. But currently the data is copied in the
same offset as the source page. This causes a hole at the start
of the reader page. This complicates the use of this function.
Instead, it should copy the data at the beginning of the function
and update the index fields accordingly.
Other small clean ups are also done in this patch.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to possible alignment problems on some archs.
Some arch compilers include an NULL char array in the sizeof field.
Since the ring_buffer_event type includes one of these, it is better
to use the "offsetof" instead, to avoid strange bugs on these archs.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The ring_buffer_read_page was broken if it were to only copy part
of the page. This patch fixes that up as well as adds a parameter
to allow a length field, in order to only copy part of the buffer page.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix ring_buffer_read_page
After a page is swapped into the ring buffer, the write field must
also be reset.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
sched: don't allow setuid to succeed if the user does not have rt bandwidth
sched_rt: don't start timer when rt bandwidth disabled
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
rcu: Teach RCU that idle task is not quiscent state at boot
The registering of events had the return value check backwards.
A zero returned is success, the check had it as a failure.
This patch also fixes a missing "\n" in the warning that the check
failed.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
On x86-64, a 32-bit process (TIF_IA32) can switch to 64-bit mode with
ljmp, and then use the "syscall" instruction to make a 64-bit system
call. A 64-bit process make a 32-bit system call with int $0x80.
In both these cases under CONFIG_SECCOMP=y, secure_computing() will use
the wrong system call number table. The fix is simple: test TS_COMPAT
instead of TIF_IA32. Here is an example exploit:
/* test case for seccomp circumvention on x86-64
There are two failure modes: compile with -m64 or compile with -m32.
The -m64 case is the worst one, because it does "chmod 777 ." (could
be any chmod call). The -m32 case demonstrates it was able to do
stat(), which can glean information but not harm anything directly.
A buggy kernel will let the test do something, print, and exit 1; a
fixed kernel will make it exit with SIGKILL before it does anything.
*/
#define _GNU_SOURCE
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <linux/prctl.h>
#include <sys/stat.h>
#include <unistd.h>
#include <asm/unistd.h>
int
main (int argc, char **argv)
{
char buf[100];
static const char dot[] = ".";
long ret;
unsigned st[24];
if (prctl (PR_SET_SECCOMP, 1, 0, 0, 0) != 0)
perror ("prctl(PR_SET_SECCOMP) -- not compiled into kernel?");
#ifdef __x86_64__
assert ((uintptr_t) dot < (1UL << 32));
asm ("int $0x80 # %0 <- %1(%2 %3)"
: "=a" (ret) : "0" (15), "b" (dot), "c" (0777));
ret = snprintf (buf, sizeof buf,
"result %ld (check mode on .!)\n", ret);
#elif defined __i386__
asm (".code32\n"
"pushl %%cs\n"
"pushl $2f\n"
"ljmpl $0x33, $1f\n"
".code64\n"
"1: syscall # %0 <- %1(%2 %3)\n"
"lretl\n"
".code32\n"
"2:"
: "=a" (ret) : "0" (4), "D" (dot), "S" (&st));
if (ret == 0)
ret = snprintf (buf, sizeof buf,
"stat . -> st_uid=%u\n", st[7]);
else
ret = snprintf (buf, sizeof buf, "result %ld\n", ret);
#else
# error "not this one"
#endif
write (1, buf, ret);
syscall (__NR_exit, 1);
return 2;
}
Signed-off-by: Roland McGrath <roland@redhat.com>
[ I don't know if anybody actually uses seccomp, but it's enabled in
at least both Fedora and SuSE kernels, so maybe somebody is. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make sure the genirq layer handlers are indeed running handlers
in hardirq context. That is the genirq expectation and doing
anything else is broken.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <1236006812.5330.632.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To be able to identify the trace in the binary format output, the
id of the trace event (which is dynamically assigned) must also be listed.
This patch adds the name of the trace point as well as the id assigned.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch includes the ftrace header to the event formats files:
# cat /debug/tracing/events/sched/sched_switch/format
field:unsigned char type; offset:0; size:1;
field:unsigned char flags; offset:1; size:1;
field:unsigned char preempt_count; offset:2; size:1;
field:int pid; offset:4; size:4;
field:int tgid; offset:8; size:4;
field:pid_t prev_pid; offset:12; size:4;
field:int prev_prio; offset:16; size:4;
field special:char next_comm[TASK_COMM_LEN]; offset:20; size:16;
field:pid_t next_pid; offset:36; size:4;
field:int next_prio; offset:40; size:4;
A blank line is used as a deliminator between the ftrace header and the
trace point fields.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds the "format" file to the trace point event directory.
This is based off of work by Tom Zanussi, in which a file is exported
to be tread from user land such that a user space app may read the
binary record stored in the ring buffer.
# cat /debug/tracing/events/sched/sched_switch/format
field:pid_t prev_pid; offset:12; size:4;
field:int prev_prio; offset:16; size:4;
field special:char next_comm[TASK_COMM_LEN]; offset:20; size:16;
field:pid_t next_pid; offset:36; size:4;
field:int next_prio; offset:40; size:4;
Idea-from: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The trace_seq functions may be used separately outside of the ftrace
iterator. The trace_seq_reset is needed for these operations.
This patch also renames trace_seq_reset to the more appropriate
trace_seq_init.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The trace event objects are currently not proctected against
reentrancy. This patch adds a mutex around the modifications of
the trace event fields.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Tom Zanussi pointed out that the simple TRACE_FIELD was not enough to
record trace data that required memcpy. This patch addresses this issue
by adding a TRACE_FIELD_SPECIAL. The format is similar to TRACE_FIELD
but looks like so:
TRACE_FIELD_SPECIAL(type_item, item, cmd)
What TRACE_FIELD gave was:
TRACE_FIELD(type, item, assign)
The TRACE_FIELD would be used in declaring a structure:
struct {
type item;
};
And later assign it via:
entry->item = assign;
What TRACE_FIELD_SPECIAL gives us is:
In the declaration of the structure:
struct {
type_item;
};
And the assignment:
cmd;
This change log will explain the one example used in the patch:
TRACE_EVENT_FORMAT(sched_switch,
TPPROTO(struct rq *rq, struct task_struct *prev,
struct task_struct *next),
TPARGS(rq, prev, next),
TPFMT("task %s:%d ==> %s:%d",
prev->comm, prev->pid, next->comm, next->pid),
TRACE_STRUCT(
TRACE_FIELD(pid_t, prev_pid, prev->pid)
TRACE_FIELD(int, prev_prio, prev->prio)
TRACE_FIELD_SPECIAL(char next_comm[TASK_COMM_LEN],
next_comm,
TPCMD(memcpy(TRACE_ENTRY->next_comm,
next->comm,
TASK_COMM_LEN)))
TRACE_FIELD(pid_t, next_pid, next->pid)
TRACE_FIELD(int, next_prio, next->prio)
),
TPRAWFMT("prev %d:%d ==> next %s:%d:%d")
);
The struct will be create as:
struct {
pid_t prev_pid;
int prev_prio;
char next_comm[TASK_COMM_LEN];
pid_t next_pid;
int next_prio;
};
Note the TRACE_ENTRY in the cmd part of TRACE_SPECIAL. TRACE_ENTRY will
be set by the tracer to point to the structure inside the trace buffer.
entry->prev_pid = prev->pid;
entry->prev_prio = prev->prio;
memcpy(entry->next_comm, next->comm, TASK_COMM_LEN);
entry->next_pid = next->pid;
entry->next_prio = next->prio
Reported-by: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: micro-optimization
Parameter "prev" is not used really.
Signed-off-by: Wang Chen <wangchen@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds the interface to enable the C style trace points.
In the directory /debugfs/tracing/events/subsystem/event
We now have three files:
enable : values 0 or 1 to enable or disable the trace event.
available_types: values 'raw' and 'printf' which indicate the tracing
types available for the trace point. If a developer does not
use the TRACE_EVENT_FORMAT macro and just uses the TRACE_FORMAT
macro, then only 'printf' will be available. This file is
read only.
type: values 'raw' or 'printf'. This indicates which type of tracing
is active for that trace point. 'printf' is the default and
if 'raw' is not available, this file is read only.
# echo raw > /debug/tracing/events/sched/sched_wakeup/type
# echo 1 > /debug/tracing/events/sched/sched_wakeup/enable
Will enable the C style tracing for the sched_wakeup trace point.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: lower overhead tracing
The current event tracer can automatically pick up trace points
that are registered with the TRACE_FORMAT macro. But it required
a printf format string and parsing. Although, this adds the ability
to get guaranteed information like task names and such, it took
a hit in overhead processing. This processing can add about 500-1000
nanoseconds overhead, but in some cases that too is considered
too much and we want to shave off as much from this overhead as
possible.
Tom Zanussi recently posted tracing patches to lkml that are based
on a nice idea about capturing the data via C structs using
STRUCT_ENTER, STRUCT_EXIT type of macros.
I liked that method very much, but did not like the implementation
that required a developer to add data/code in several disjoint
locations.
This patch extends the event_tracer macros to do a similar "raw C"
approach that Tom Zanussi did. But instead of having the developers
needing to tweak a bunch of code all over the place, they can do it
all in one macro - preferably placed near the code that it is
tracing. That makes it much more likely that tracepoints will be
maintained on an ongoing basis by the code they modify.
The new macro TRACE_EVENT_FORMAT is created for this approach. (Note,
a developer may still utilize the more low level DECLARE_TRACE macros
if they don't care about getting their traces automatically in the event
tracer.)
They can also use the existing TRACE_FORMAT if they don't need to code
the tracepoint in C, but just want to use the convenience of printf.
So if the developer wants to "hardwire" a tracepoint in the fastest
possible way, and wants to acquire their data via a user space utility
in a raw binary format, or wants to see it in the trace output but not
sacrifice any performance, then they can implement the faster but
more complex TRACE_EVENT_FORMAT macro.
Here's what usage looks like:
TRACE_EVENT_FORMAT(name,
TPPROTO(proto),
TPARGS(args),
TPFMT(fmt, fmt_args),
TRACE_STUCT(
TRACE_FIELD(type1, item1, assign1)
TRACE_FIELD(type2, item2, assign2)
[...]
),
TPRAWFMT(raw_fmt)
);
Note name, proto, args, and fmt, are all identical to what TRACE_FORMAT
uses.
name: is the unique identifier of the trace point
proto: The proto type that the trace point uses
args: the args in the proto type
fmt: printf format to use with the event printf tracer
fmt_args: the printf argments to match fmt
TRACE_STRUCT starts the ability to create a structure.
Each item in the structure is defined with a TRACE_FIELD
TRACE_FIELD(type, item, assign)
type: the C type of item.
item: the name of the item in the stucture
assign: what to assign the item in the trace point callback
raw_fmt is a way to pretty print the struct. It must match
the order of the items are added in TRACE_STUCT
An example of this would be:
TRACE_EVENT_FORMAT(sched_wakeup,
TPPROTO(struct rq *rq, struct task_struct *p, int success),
TPARGS(rq, p, success),
TPFMT("task %s:%d %s",
p->comm, p->pid, success?"succeeded":"failed"),
TRACE_STRUCT(
TRACE_FIELD(pid_t, pid, p->pid)
TRACE_FIELD(int, success, success)
),
TPRAWFMT("task %d success=%d")
);
This creates us a unique struct of:
struct {
pid_t pid;
int success;
};
And the way the call back would assign these values would be:
entry->pid = p->pid;
entry->success = success;
The nice part about this is that the creation of the assignent is done
via macro magic in the event tracer. Once the TRACE_EVENT_FORMAT is
created, the developer will then have a faster method to record
into the ring buffer. They do not need to worry about the tracer itself.
The developer would only need to touch the files in include/trace/*.h
Again, I would like to give special thanks to Tom Zanussi for this
nice idea.
Idea-from: Tom Zanussi <tzanussi@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Right now all tracers must manage their own trace buffers. This was
to enforce tracers to be independent in case we finally decide to
allow each tracer to have their own trace buffer.
But now we are adding event tracing that writes to the current tracer's
buffer. This adds an interface to allow events to write to the current
tracer buffer without having to manage its own. Since event tracing
has no "tracer", and is just a way to hook into any other tracer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch makes the event files, set_event and available_events
aware of the subsystem.
Now you can enable an entire subsystem with:
echo 'irq:*' > set_event
Note: the '*' is not needed.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
If a trace point header defines TRACE_SYSTEM, then it will add the
following trace points into that event system.
If include/trace/irq_event_types.h has:
#define TRACE_SYSTEM irq
at the top and
#undef TRACE_SYSTEM
at the bottom, then a directory "irq" will be created in the
/debug/tracing/events directory. Inside that directory will contain the
two trace points that are defined in include/trace/irq_event_types.h.
Only adding the above to irq and not to sched, we get:
# ls /debug/tracing/events/
irq sched_process_exit sched_signal_send sched_wakeup_new
sched_kthread_stop sched_process_fork sched_switch
sched_kthread_stop_ret sched_process_free sched_wait_task
sched_migrate_task sched_process_wait sched_wakeup
# ls /debug/tracing/events/irq
irq_handler_entry irq_handler_exit
If we add #define TRACE_SYSTEM sched to the trace/sched_event_types.h
then the rest of the trace events will be put in a sched directory
within the events directory.
I've been playing with this idea of the subsystem for a while, but
recently Tom Zanussi posted some patches to lkml that included this
method. Tom's approach was clean and got me to finally put some effort
to clean up the event trace points.
Thanks to Tom Zanussi for demonstrating how nice the subsystem
method is.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
To further facilitate the ease of adding trace points for developers, this
patch creates include/trace/trace_events.h and
include/trace/trace_event_types.h.
The former file will hold the trace/<type>.h files and the latter will hold
the trace/<type>_event_types.h files.
To create new tracepoints and to have them automatically
appear in the event tracer, a developer makes the trace/<type>.h file
which includes <linux/tracepoint.h> and the trace/<type>_event_types.h file.
The trace/<type>_event_types.h file will hold the TRACE_FORMAT
macros.
Then add the trace/<type>.h file to trace/trace_events.h,
and add the trace/<type>_event_types.h to the trace_event_types.h file.
No need to modify files elsewhere.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
free_uid() and free_user_ns() are corecursive when CONFIG_USER_SCHED=n,
but free_user_ns() is called from free_uid() by way of uid_hash_remove(),
which requires uidhash_lock to be held. free_user_ns() then calls
free_uid() to complete the destruction.
Fix this by deferring the destruction of the user_namespace.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: clean up
kcalloc is a better approach to allocate a NULL array.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix hung task with certain (non-default) rt-limit settings
Corey Hickey reported that on using setuid to change the uid of a
rt process, the process would be unkillable and not be running.
This is because there was no rt runtime for that user group. Add
in a check to see if a user can attach an rt task to its task group.
On failure, return EINVAL, which is also returned in
CONFIG_CGROUP_SCHED.
Reported-by: Corey Hickey <bugfood-ml@fatooh.org>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix compile warning and clean up
When I first wrote __tracing_open, instead of passing the error
code via the ERR_PTR macros, I lazily used a separate parameter
to hold the return for errors.
When Frederic Weisbecker updated that function, he used the Linux
kernel ERR_PTR for the returns. This caused the parameter return
to possibly not be initialized on error. gcc correctly pointed this
out with a warning.
This patch converts the entire function to use the Linux kernel
ERR_PTR macro methods.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to possible race conditions
There's some uses of current_tracer that is not protected by the
trace_types_lock. There is a small chance that a sysadmin changes
the tracer while the current_tracer is being referenced.
If the race is hit, it is unlikely to cause any harm since the
tracers are constant and are not freed. But some strang side
effects may occur.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds the tracer dependent options dynamically to the
options directory when the tracer is activated. These options are
removed when the tracer is deactivated.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch creates an options directory in the debugfs, that contains
the available tracing options. These files contain 1 or 0, where 1
is the option is enabled and 0 it is disabled.
Simply echoing in 1 will enable the option and 0 will disable it.
This patch only contains the core options, not the tracer options.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
per-uid keys were looked by uid only. Use the user namespace
to distinguish the same uid in different namespaces.
This does not address key_permission. So a task can for instance
try to join a keyring owned by the same uid in another namespace.
That will be handled by a separate patch.
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
- remove superfluous checks in __update_sched_clock()
- skip sched_clock_tick() for sched_clock_stable
- reinstate the simple !HAVE_UNSTABLE_SCHED_CLOCK code to please the bloatwatch
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Allow CONFIG_HAVE_UNSTABLE_SCHED_CLOCK architectures to still specify
that their sched_clock() implementation is reliable.
This will be used by x86 to switch on a faster sched_clock_cpu()
implementation on certain CPU types.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The time_status conditional was accidentally placed right after we clear
the checked time_status bits, which causes us to take the conditional
every time through. This fixes it by moving the conditional to before we
clear the time_status bits.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Clark Williams <williams@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: implement new tracing timestamp APIs
Add three trace clock variants, with differing scalability/precision
tradeoffs:
- local: CPU-local trace clock
- medium: scalable global clock with some jitter
- global: globally monotonic, serialized clock
Make the ring-buffer use the local trace clock internally.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
make sure we dont execute more complex sched_clock() code in NMI context.
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: add new tracepoints
Add them to the generic IRQ code, that way every architecture
gets these new tracepoints, not just x86.
Using Steve's new 'TRACE_FORMAT', I can get function graph
trace as follows using the original two IRQ tracepoints:
3) | handle_IRQ_event() {
3) | /* (irq_handler_entry) irq=28 handler=eth0 */
3) | e1000_intr_msi() {
3) 2.460 us | __napi_schedule();
3) 9.416 us | }
3) | /* (irq_handler_exit) irq=28 handler=eth0 return=handled */
3) + 22.935 us | }
Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mathieu Desnoyers <compudj@krystal.dyndns.org>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix incorrect condition check
No need to start rt bandwidth timer when rt bandwidth is disabled.
If this timer starts, it may stop at sched_rt_period_timer() on the first time.
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: restructure the VFS layout of per CPU trace buffers
The per cpu trace files are all in a single directory:
/debug/tracing/per_cpu. In case of a large number of cpu, the
content of this directory becomes messy so we create now one
directory per cpu inside /debug/tracing/per_cpu which contain
each their own trace_pipe and trace files.
Ie:
/debug/tracing$ ls -R per_cpu
per_cpu:
cpu0 cpu1
per_cpu/cpu0:
trace trace_pipe
per_cpu/cpu1:
trace trace_pipe
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
cpuacct_charge() is in fast-path, and checking of !cpuacct_susys.active
always returns false after cpuacct has been initialized at system boot.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch fixes a bug located by Vegard Nossum with the aid of
kmemcheck, updated based on review comments from Nick Piggin,
Ingo Molnar, and Andrew Morton. And cleans up the variable-name
and function-name language. ;-)
The boot CPU runs in the context of its idle thread during boot-up.
During this time, idle_cpu(0) will always return nonzero, which will
fool Classic and Hierarchical RCU into deciding that a large chunk of
the boot-up sequence is a big long quiescent state. This in turn causes
RCU to prematurely end grace periods during this time.
This patch changes the rcutree.c and rcuclassic.c rcu_check_callbacks()
function to ignore the idle task as a quiescent state until the
system has started up the scheduler in rest_init(), introducing a
new non-API function rcu_idle_now_means_idle() to inform RCU of this
transition. RCU maintains an internal rcu_idle_cpu_truthful variable
to track this state, which is then used by rcu_check_callback() to
determine if it should believe idle_cpu().
Because this patch has the effect of disallowing RCU grace periods
during long stretches of the boot-up sequence, this patch also introduces
Josh Triplett's UP-only optimization that makes synchronize_rcu() be a
no-op if num_online_cpus() returns 1. This allows boot-time code that
calls synchronize_rcu() to proceed normally. Note, however, that RCU
callbacks registered by call_rcu() will likely queue up until later in
the boot sequence. Although rcuclassic and rcutree can also use this
same optimization after boot completes, rcupreempt must restrict its
use of this optimization to the portion of the boot sequence before the
scheduler starts up, given that an rcupreempt RCU read-side critical
section may be preeempted.
In addition, this patch takes Nick Piggin's suggestion to make the
system_state global variable be __read_mostly.
Changes since v4:
o Changes the name of the introduced function and variable to
be less emotional. ;-)
Changes since v3:
o WARN_ON(nr_context_switches() > 0) to verify that RCU
switches out of boot-time mode before the first context
switch, as suggested by Nick Piggin.
Changes since v2:
o Created rcu_blocking_is_gp() internal-to-RCU API that
determines whether a call to synchronize_rcu() is itself
a grace period.
o The definition of rcu_blocking_is_gp() for rcuclassic and
rcutree checks to see if but a single CPU is online.
o The definition of rcu_blocking_is_gp() for rcupreempt
checks to see both if but a single CPU is online and if
the system is still in early boot.
This allows rcupreempt to again work correctly if running
on a single CPU after booting is complete.
o Added check to rcupreempt's synchronize_sched() for there
being but one online CPU.
Tested all three variants both SMP and !SMP, booted fine, passed a short
rcutorture test on both x86 and Power.
Located-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@gmail.com>
Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
There's been a bit confusion to whether DEFINE/DECLARE_TRACE_FMT should
be a DEFINE or a DECLARE. Ingo Molnar suggested simply calling it
TRACE_FORMAT.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup, no functionality changed
The 'time_adj' local variable is named in a very confusing
way because it almost shadows the 'time_adjust' global
variable - which is used in this same function.
Rename it to 'delta' - to make them stand apart more clearly.
kernel/time/ntp.o:
text data bss dec hex filename
2545 114 144 2803 af3 ntp.o.before
2545 114 144 2803 af3 ntp.o.after
md5:
1bf0b3be564512279ba7cee299d1d2be ntp.o.before.asm
1bf0b3be564512279ba7cee299d1d2be ntp.o.after.asm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: micro-optimization
Convert the (internal) ntp_tick_adj value we store from unscaled
units to scaled units. This is a constant that we never modify,
so scaling it up once during bootup is enough - we dont have to
do it for every adjustment step.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
Further simplify do_adjtimex():
- introduce the ntp_start_leap_timer() helper function
- eliminate the goto adj_done complication
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
do_adjtimex() is currently a monster function with a maze of
branches. Refactor the txc->modes setting aspects of it into
two new helper functions:
process_adj_status()
process_adjtimex_modes()
kernel/time/ntp.o:
text data bss dec hex filename
2512 114 136 2762 aca ntp.o.before
2512 114 136 2762 aca ntp.o.after
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: change (fix) the way the NTP PLL seconds offset is initialized/tracked
Fix a bug and do a micro-optimization:
When PLL is enabled we do not reset time_reftime. If the PLL
was off for a long time (for example after bootup), this is
arguably the wrong thing to do.
We already had a hack for the common boot-time case in
ntp_update_offset(), in form of:
if (unlikely(time_status & STA_FREQHOLD || time_reftime == 0))
secs = 0;
But the update delta should be reset later on too - not just when
the PLL is enabled for the first time after bootup.
So do it on !STA_PLL -> STA_PLL transitions.
This changes behavior, as previously if ntpd was disabled for
a long time and we restarted it, we'd run from that last update,
with a very large delta.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
The time_reftime update in ntp_update_offset() to xtime.tv_sec
is a convoluted way of saying that we want to freeze the frequency
and want the 'secs' delta to be 0. Also make this branch unlikely.
This shaves off 8 bytes from the code size:
text data bss dec hex filename
2504 114 136 2754 ac2 ntp.o.before
2496 114 136 2746 aba ntp.o.after
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
Change ntp_update_offset_fll() to delta logic instead of
absolute value logic. This eliminates 'freq_adj' from the
function.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
Change ntp_update_frequency() from a hard to follow code
flow that uses global variables as temporaries, to a clean
input+output flow.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
There's an ugly u64 typecase in the MAX_TICKADJ_SCALED definition,
this can be eliminated by making the MAX_TICKADJ constant's type
64-bit (signed).
kernel/time/ntp.o:
text data bss dec hex filename
2504 114 136 2754 ac2 ntp.o.before
2504 114 136 2754 ac2 ntp.o.after
md5:
41f3009debc9b397d7394dd77d912f0a ntp.o.before.asm
41f3009debc9b397d7394dd77d912f0a ntp.o.after.asm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
Instead of a hierarchy of conditions, transform them to clean
gradual conditions and return's.
This makes the flow easier to read and makes the purpose of
the function easier to understand.
kernel/time/ntp.o:
text data bss dec hex filename
2552 170 168 2890 b4a ntp.o.before
2552 170 168 2890 b4a ntp.o.after
md5:
eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.before.asm
eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.after.asm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup, no functionality changed
Make this file a bit more readable by applying a consistent coding style.
No code changed:
kernel/time/ntp.o:
text data bss dec hex filename
2552 170 168 2890 b4a ntp.o.before
2552 170 168 2890 b4a ntp.o.after
md5:
eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.before.asm
eae1275df0b7d6290c13f6f6f8f05c8c ntp.o.after.asm
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew pointed out that there's some small amount of
style rot in kernel/smp.c.
Clean it up.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Oleg noticed that we don't strictly need CSD_FLAG_WAIT, rework
the code so that we can use CSD_FLAG_LOCK for both purposes.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Remove the use of kmalloc() from the smp_call_function_*()
calls.
Steven's generic-ipi patch (d7240b98: generic-ipi: use per cpu
data for single cpu ipi calls) started the discussion on the use
of kmalloc() in this code and fixed the
smp_call_function_single(.wait=0) fallback case.
In this patch we complete this by also providing means for the
_many() call, which fully removes the need for kmalloc() in this
code.
The problem with the _many() call is that other cpus might still
be observing our entry when we're done with it. It solved this
by dynamically allocating data elements and RCU-freeing it.
We solve it by using a single per-cpu entry which provides
static storage and solves one half of the problem (avoiding
referencing freed data).
The other half, ensuring the queue iteration it still possible,
is done by placing re-used entries at the head of the list. This
means that if someone was still iterating that entry when it got
moved, he will now re-visit the entries on the list he had
already seen, but avoids skipping over entries like would have
happened had we placed the new entry at the end.
Furthermore, visiting entries twice is not a problem, since we
remove our cpu from the entry's cpumask once its called.
Many thanks to Oleg for his suggestions and him poking holes in
my earlier attempts.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that several per-cpu files can be read or spliced at the
same, we want the read/splice callbacks for tracing files to be
reentrants.
Until now, a single global mutex (trace_types_lock) serialized
the access to tracing_read_pipe(), tracing_splice_read_pipe(),
and the seq helpers.
Ie: it means that if a user tries to read trace_pipe0 and
trace_pipe1 at the same time, the access to the function
tracing_read_pipe() is contended and one reader must wait for
the other to finish its read call.
The trace_type_lock mutex is mostly here to serialize the access
to the global current tracer (current_trace), which can be
changed concurrently. Although the iter struct keeps a private
pointer to this tracer, its callbacks can be changed by another
function.
The method used here is to not keep anymore private reference to
the tracer inside the iterator but to make a copy of it inside
the iterator. Then it checks on subsequents read calls if the
tracer has changed. This is not costly because the current
tracer is not expected to be changed often, so we use a branch
prediction for that.
Moreover, we add a private mutex to the iterator (there is one
iterator per file descriptor) to serialize the accesses in case
of multiple consumers per file descriptor (which would be a
silly idea from the user). Note that this is not to protect the
ring buffer, since the ring buffer already serializes the
readers accesses. This is to prevent from traces weirdness in
case of concurrent consumers. But these mutexes can be dropped
anyway, that would not result in any crash. Just tell me what
you think about it.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: split up tracing output per cpu
Currently, on the tracing debugfs directory, three files are
available to the user to let him extracting the trace output:
- trace is an iterator through the ring-buffer. It's a reader
but not a consumer It doesn't block when no more traces are
available.
- trace pretty similar to the former, except that it adds more
informations such as prempt count, irq flag, ...
- trace_pipe is a reader and a consumer, it will also block
waiting for traces if necessary (heh, yes it's a pipe).
The traces coming from different cpus are curretly mixed up
inside these files. Sometimes it messes up the informations,
sometimes it's useful, depending on what does the tracer
capture.
The tracing_cpumask file is useful to filter the output and
select only the traces captured a custom defined set of cpus.
But still it is not enough powerful to extract at the same time
one trace buffer per cpu.
So this patch creates a new directory: /debug/tracing/per_cpu/.
Inside this directory, you will now find one trace_pipe file and
one trace file per cpu.
Which means if you have two cpus, you will have:
trace0
trace1
trace_pipe0
trace_pipe1
And of course, reading these files will have the same effect
than with the usual tracing files, except that you will only see
the traces from the given cpu.
The original all-in-one cpu trace file are still available on
their original place.
Until now, only one consumer was allowed on trace_pipe to avoid
racy consuming on the ring-buffer. Now the approach changed a
bit, you can have only one consumer per cpu.
Which means you are allowed to read concurrently trace_pipe0 and
trace_pipe1 But you can't have two readers on trace_pipe0 or
trace_pipe1.
Following the same logic, if there is one reader on the common
trace_pipe, you can not have at the same time another reader on
trace_pipe0 or in trace_pipe1. Because in trace_pipe is already
a consumer in all cpu buffers in essence.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simplify the barriers in generic remote function call interrupt
code.
Firstly, just unconditionally take the lock and check the list
in the generic_call_function_single_interrupt IPI handler. As
we've just taken an IPI here, the chances are fairly high that
there will be work on the list for us, so do the locking
unconditionally. This removes the tricky lockless list_empty
check and dubious barriers. The change looks bigger than it is
because it is just removing an outer loop.
Secondly, clarify architecture specific IPI locking rules.
Generic code has no tools to impose any sane ordering on IPIs if
they go outside normal cache coherency, ergo the arch code must
make them appear to obey cache coherency as a "memory operation"
to initiate an IPI, and a "memory operation" to receive one.
This way at least they can be reasoned about in generic code,
and smp_mb used to provide ordering.
The combination of these two changes means that explict barriers
can be taken out of queue handling for the single case -- shared
data is explicitly locked, and ipi ordering must conform to
that, so no barriers needed. An extra barrier is needed in the
many handler, so as to ensure we load the list element after the
IPI is received.
Does any architecture actually *need* these barriers? For the
initiator I could see it, but for the handler I would be
surprised. So the other thing we could do for simplicity is just
to require that, rather than just matching with cache coherency,
we just require a full barrier before generating an IPI, and
after receiving an IPI. In which case, the smp_mb()s can go
away. But just for now, we'll be on the safe side and use the
barriers (they're in the slow case anyway).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-arch@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: remove old debug/tracing API
/debug/tracing/latency_trace is an old legacy format we kept from
the old latency tracer. Remove the file for now. If there's any
useful bit missing then we'll propagate any useful output bits into
the /debug/tracing/trace output.
Reported-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: fix CPU hotplug lockup
bts_hotcpu_handler() is called with irqs disabled, so using mutex_lock()
is a no-no.
All the BTS codepaths here are atomic (they do not schedule), so using
a spinlock is the right solution.
Cc: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch adds the directory /debug/tracing/events/ that will contain
all the registered trace points.
# ls /debug/tracing/events/
sched_kthread_stop sched_process_fork sched_switch
sched_kthread_stop_ret sched_process_free sched_wait_task
sched_migrate_task sched_process_wait sched_wakeup
sched_process_exit sched_signal_send sched_wakeup_new
# ls /debug/tracing/events/sched_switch/
enable
# cat /debug/tracing/events/sched_switch/enable
1
# cat /debug/tracing/set_event
sched_switch
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch changes the trace/sched.h to use the DECLARE_TRACE_FMT
such that they are automatically registered with the event tracer.
And it also adds the tracing sched headers to kernel/trace/events.c
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch creates the event tracing infrastructure of ftrace.
It will create the files:
/debug/tracing/available_events
/debug/tracing/set_event
The available_events will list the trace points that have been
registered with the event tracer.
set_events will allow the user to enable or disable an event hook.
example:
# echo sched_wakeup > /debug/tracing/set_event
Will enable the sched_wakeup event (if it is registered).
# echo "!sched_wakeup" >> /debug/tracing/set_event
Will disable the sched_wakeup event (and only that event).
# echo > /debug/tracing/set_event
Will disable all events (notice the '>')
# cat /debug/tracing/available_events > /debug/tracing/set_event
Will enable all registered event hooks.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Fix an invalid memory reference problem when cpu hotplug support is
disabled and the hw-branch-tracer is set as current tracer.
Initializing the tracer calls bts_trace_init() which has already
been freed at this time.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Move the sysdev_suspend/resume from the callee to the callers, with
no real change in semantics, so that we can rework the disabling of
interrupts during suspend/hibernation.
This is based on an earlier patch from Linus.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* hibernate:
PM: Fix suspend_console and resume_console to use only one semaphore
PM: Wait for console in resume
PM: Fix pm_notifiers during user mode hibernation
swsusp: clean up shrink_all_zones()
swsusp: dont fiddle with swappiness
PM: fix build for CONFIG_PM unset
PM/hibernate: fix "swap breaks after hibernation failures"
PM/resume: wait for device probing to finish
Consolidate driver_probe_done() loops into one place
This fixes a race where a thread acquires the console while the
console is suspended, and the console is resumed before this
thread releases it. In this case, the secondary console
semaphore would be left locked, and the primary semaphore would
be released twice. This in turn would cause the console switch
on suspend or resume to hang forever.
Note that suspend_console does not actually lock the console
for clients that use acquire_console_sem, it only locks it for
clients that use try_acquire_console_sem. If we change
suspend_console to fully lock the console, then the kernel
may deadlock on suspend. One client of try_acquire_console_sem
is acquire_console_semaphore_for_printk, which uses it to
prevent printk from using the console while it is suspended.
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoids later waking up to a blinking cursor if the device woke up and
returned to sleep before the console switch happened.
Signed-off-by: Brian Swetland <swetland@google.com>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Snapshot device is opened with O_RDONLY during suspend and O_WRONLY durig
resume. Make sure we also call notifiers with correct parameter telling
them what we are really doing.
Signed-off-by: Andrey Borzenkov <arvidjaar@mail.ru>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Compilation of kprobes.c with CONFIG_PM unset is broken due to some broken
config dependncies. Fix that.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg KH <gregkh@suse.de>
Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Masami Hiramatsu <mhiramat@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
the resume code does not currently wait for device probing to finish.
Even without async function calls this is dicey and not correct,
but with async function calls during the boot sequence this is going
to get hit more...
This patch adds the synchronization using the newly introduced helper.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Greg KH <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: added precaution on failure detection
Break out of the modifying loop as soon as a failure is detected.
This is just an added precaution found by code review and was not
found by any bug chasing.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch creates the weak functions: ftrace_arch_code_modify_prepare
and ftrace_arch_code_modify_post_process that are called before and
after the stop machine is called to modify the kernel text.
If the arch needs to do pre or post processing, it only needs to define
these functions.
[ Update: Ingo Molnar suggested using the name ftrace_arch_code_modify_*
over using ftrace_arch_modify_* ]
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: trace only functions matching a pattern
The set_graph_function file let one to trace only one or several
chosen functions and follow all their code flow.
Currently, only a constant function name is allowed so this patch
allows the ftrace_regex functions:
- matches all functions that end with "name":
echo *name > set_graph_function
- matches all functions that begin with "name":
echo name* > set_graph_function
- matches all functions that contains "name":
echo *name* > set_graph_function
Example:
echo mutex* > set_graph_function
0) | mutex_lock_nested() {
0) 0.563 us | __might_sleep();
0) 2.072 us | }
0) | mutex_unlock() {
0) 1.036 us | __mutex_unlock_slowpath();
0) 2.433 us | }
0) | mutex_unlock() {
0) 0.691 us | __mutex_unlock_slowpath();
0) 1.787 us | }
0) | mutex_lock_interruptible_nested() {
0) 0.548 us | __might_sleep();
0) 1.945 us | }
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new scalable dynamic percpu allocator which allows dynamic
percpu areas to be accessed the same way as static ones
Implement scalable dynamic percpu allocator which can be used for both
static and dynamic percpu areas. This will allow static and dynamic
areas to share faster direct access methods. This feature is optional
and enabled only when CONFIG_HAVE_DYNAMIC_PER_CPU_AREA is defined by
arch. Please read comment on top of mm/percpu.c for details.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Impact: cleanup
There are two allocated per-cpu accessor macros with almost identical
spelling. The original and far more popular is per_cpu_ptr (44
files), so change over the other 4 files.
tj: kill percpu_ptr() and update UP too
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: mingo@redhat.com
Cc: lenb@kernel.org
Cc: cpufreq@vger.kernel.org
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
tracing: limit the number of loops the ring buffer self test can make
tracing: have function trace select kallsyms
tracing: disable tracing while testing ring buffer
tracing/function-graph-tracer: trace the idle tasks
Since the GENERIC_TIME changes landed, the adjtimex behavior changed
for struct timex.tick and .freq changed. When the tick or freq value
is set, we adjust the tick_length_base in ntp_update_frequency().
However, this new value doesn't get applied to tick_length until the
next second (via second_overflow).
This means some applications that do quick time tweaking do not see the
requested change made as quickly as expected.
I've run a few tests with this change, and ntpd still functions fine.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: prevent deadlock if ring buffer gets corrupted
This patch adds a paranoid check to make sure the ring buffer consumer
does not go into an infinite loop. Since the ring buffer has been set
to read only, the consumer should not loop for more than the ring buffer
size. A check is added to make sure the consumer does not loop more than
the ring buffer size.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix output of function tracer to be useful
The function tracer is pretty useless if KALLSYMS is not configured.
Unless you are good at reading hex values, the function tracer should
select the KALLSYMS configuration.
Also, the dynamic function tracer will fail its self test if KALLSYMS
is not selected.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to prevent hard lockup on self tests
If one of the tracers are broken and is constantly filling the ring
buffer while the test of the ring buffer is running, it will hang
the box. The reason is that the test is a consumer that will not
stop till the ring buffer is empty. But if the tracer is broken and
is constantly producing input to the buffer, this test will never
end. The result is a lockup of the box.
This happened when KALLSYMS was not defined and the dynamic ftrace
test constantly filled the ring buffer, because the filter failed
and all functions were being traced. Something was being called
that constantly filled the buffer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
* 'for-linus' of git://git.kernel.dk/linux-2.6-block:
block: fix deadlock in blk_abort_queue() for drivers that readd to timeout list
block: fix booting from partitioned md array
block: revert part of 18ce3751cc
cciss: PCI power management reset for kexec
paride/pg.c: xs(): &&/|| confusion
fs/bio: bio_alloc_bioset: pass right object ptr to mempool_free
block: fix bad definition of BIO_RW_SYNC
bsg: Fix sense buffer bug in SG_IO
Compilation of kprobes.c with CONFIG_PM unset is broken due to some broken
config dependncies. Fix that.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In cgroup_kill_sb(), root is freed before sb is detached from the list, so
another sget() may find this sb and call cgroup_test_super(), which will
access the root that has been freed.
Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is nothing really arch specific of the push and pop functions
used by the function graph tracer. This patch moves them to generic
code.
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: new timer API
Based on an idea from Martin Josefsson with the help of
Patrick McHardy and Stephen Hemminger:
introduce the mod_timer_pending() API which is a mod_timer()
offspring that is an invariant on already removed timers.
(regular mod_timer() re-activates non-pending timers.)
This is useful for the networking code in that it can
allow unserialized mod_timer_pending() timer-forwarding
calls, but a single del_timer*() will stop the timer
from being reactivated again.
Also while at it:
- optimize the regular mod_timer() path some more, the
timer-stat and a debug check was needlessly duplicated
in __mod_timer().
- make the exports come straight after the function, as
most other exports in timer.c already did.
- eliminate __mod_timer() as an external API, change the
users to mod_timer().
The regular mod_timer() code path is not impacted
significantly, due to inlining optimizations and due to
the simplifications.
Based-on-patch-from: Stephen Hemminger <shemminger@vyatta.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Cc: netdev@vger.kernel.org
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
We can't OR shift values, so get rid of BIO_RW_SYNC and use BIO_RW_SYNCIO
and BIO_RW_UNPLUG explicitly. This brings back the behaviour from before
213d9417fe.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Impact: api and pipe waiting change
Currently, the waiting used in tracing_read_pipe() is done through a
100 msecs schedule_timeout() loop which periodically check if there
are traces on the buffer.
This can cause small latencies for programs which are reading the incoming
events.
This patch makes the reader waiting for the trace_wait waitqueue except
for few tracers such as the sched and functions tracers which might be
already hold the runqueue lock while waking up the reader.
This is performed through a new callback wait_pipe() on struct tracer.
If none is implemented on a specific tracer, the default waiting for
trace_wait queue is attached.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'tracing-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
doc: mmiotrace.txt, buffer size control change
trace: mmiotrace to the tracer menu in Kconfig
mmiotrace: count events lost due to not recording
'p' stands for pointer - make it clear in setup_irq() and free_irq()
what kind of pointer it is.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Linus noticed that the 'pp' variable can be eliminated
altogether, and the loop can be cleaned up further.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
The traceon and traceoff function probes are confusing to developers
to what happens when a counter is not specified. This should help
clear things up.
# echo "*:traceoff" > set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
#### all functions enabled ####
do_fork:traceoff:unlimited
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: cleanup
Fix incorrect hint message in code and typos in comments.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch is to fix the return value of trace_selftest_startup_sysprof
and trace_selftest_startup_branch on failure.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Pass tsk to tracing_record_cmdline instead of current.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
Ingo Molnar did not like the _hook naming convention used by the
select function tracer. Luis Claudio R. Goncalves suggested using
the "_probe" extension. This patch implements the change of
calling the functions and variables "_hook" and replacing them
with "_probe".
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Ingo Molnar pointed out some coding style issues with the recent ftrace
updates. This patch cleans them up.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds a pretty print version of traceon and traceoff
output for set_ftrace_filter.
# echo 'sys_open:traceon:4' > set_ftrace_filter
# cat set_ftrace_filter
#### all functions enabled ####
sys_open:traceon:count=4
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds a call back for the tracers that have hooks to
selected functions. This allows the tracer to show better output
in the set_ftrace_filter file.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds output to show what functions have tracer hooks
attached to them.
# echo 'sys_open:traceon:4' > /debug/tracing/set_ftrace_filter
# cat set_ftrace_filter
#### all functions enabled ####
sys_open:ftrace_traceon:0000000000000004
# echo 'do_fork:traceoff:' > set_ftrace_filter
# cat set_ftrace_filter
#### all functions enabled ####
sys_open:ftrace_traceon:0000000000000002
do_fork:ftrace_traceoff:ffffffffffffffff
Note the 4 changed to a 2. This is because The code was executed twice
since the traceoff was added. If a cat is done again:
#### all functions enabled ####
sys_open:ftrace_traceon
do_fork:ftrace_traceoff:ffffffffffffffff
The number disappears. That is because it will not print a NULL.
Callbacks to allow the tracer to pretty print will be implemented soon.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds the new function selection commands traceon and
traceoff. traceon sets the function to enable the ring buffers
while traceoff disables the ring buffers. You can pass in the
number of times you want the command to be executed when the function
is hit. It will only execute if the state of the buffers are not
already in that state.
Example:
# echo do_fork:traceon:4
Will enable the ring buffers if they are disabled every time it
hits do_fork, up to 4 times.
# echo sys_close:traceoff
This will disable the ring buffers every time (unlimited) when
sys_close is called.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: new feature
Currently, the function tracer only gives you an ability to hook
a tracer to all functions being traced. The dynamic function trace
allows you to pick and choose which of those functions will be
traced, but all functions being traced will call all tracers that
registered with the function tracer.
This patch adds a new feature that allows a tracer to hook to specific
functions, even when all functions are being traced. It allows for
different functions to call different tracer hooks.
The way this is accomplished is by a special function that will hook
to the function tracer and will set up a hash table knowing which
tracer hook to call with which function. This is the most general
and easiest method to accomplish this. Later, an arch may choose
to supply their own method in changing the mcount call of a function
to call a different tracer. But that will be an exercise for the
future.
To register a function:
struct ftrace_hook_ops {
void (*func)(unsigned long ip,
unsigned long parent_ip,
void **data);
int (*callback)(unsigned long ip, void **data);
void (*free)(void **data);
};
int register_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
void *data);
glob is a simple glob to search for the functions to hook.
ops is a pointer to the operations (listed below)
data is the default data to be passed to the hook functions when traced
ops:
func is the hook function to call when the functions are traced
callback is a callback function that is called when setting up the hash.
That is, if the tracer needs to do something special for each
function, that is being traced, and wants to give each function
its own data. The address of the entry data is passed to this
callback, so that the callback may wish to update the entry to
whatever it would like.
free is a callback for when the entry is freed. In case the tracer
allocated any data, it is give the chance to free it.
To unregister we have three functions:
void
unregister_ftrace_function_hook(char *glob, struct ftrace_hook_ops *ops,
void *data)
This will unregister all hooks that match glob, point to ops, and
have its data matching data. (note, if glob is NULL, blank or '*',
all functions will be tested).
void
unregister_ftrace_function_hook_func(char *glob,
struct ftrace_hook_ops *ops)
This will unregister all functions matching glob that has an entry
pointing to ops.
void unregister_ftrace_function_hook_all(char *glob)
This simply unregisters all funcs.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
Now that ftrace_lock is a mutex, there is no reason to have three
different mutexes protecting similar data. All the mutex paths
are not in hot paths, so having a mutex to cover more data is
not a problem.
This patch removes the ftrace_sysctl_lock and ftrace_start_lock
and uses the ftrace_lock to protect the locations that were protected
by these locks. By doing so, this change also removes some of
the lock nesting that was taking place.
There are still more mutexes in ftrace.c that can probably be
consolidated, but they can be dealt with later. We need to be careful
about the way the locks are nested, and by consolidating, we can cause
a recursive deadlock.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
The older versions of ftrace required doing the ftrace list
search under atomic context. Now all the calls are in non-atomic
context. There is no reason to keep the ftrace_lock as a spinlock.
This patch converts it to a mutex.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Allow for other tracers to add their own commands for function
selection. This interface gives a trace the ability to name a
command for function selection. Right now it is pretty limited
in what it offers, but this is a building step for more features.
The :mod: command is converted to this interface and also serves
as a template for other implementations.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to prevent empty set_ftrace_filter and no ftrace output
The function filter is used to only trace a given set of functions.
The filter is enabled when a function name is echoed into the
set_ftrace_filter file. But if the name has a typo and the function
is not found, the filter is enabled, but no function is listed.
This makes a confusing situation where set_ftrace_filter is empty
but no functions ever get enabled for tracing.
For example:
# cat /debug/tracing/set_ftrace_filter
#### all functions enabled ####
# echo bad_name > set_ftrace_filter
# cat /debug/tracing/set_ftrace_filter
# echo function > current_tracer
# cat trace
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
This patch changes that to only enable filtering if a function
is set to be filtered on. Now, the filter is not enabled if
a bad name is echoed into set_ftrace_filter.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This patch adds a "command" syntax to the function filtering files:
/debugfs/tracing/set_ftrace_filter
/debugfs/tracing/set_ftrace_notrace
Of the format: <function>:<command>:<parameter>
The command is optional, and dependent on the command, so are
the parameters.
echo do_fork > set_ftrace_filter
Will only trace 'do_fork'.
echo 'sched_*' > set_ftrace_filter
Will only trace functions starting with the letters 'sched_'.
echo '*:mod:ext3' > set_ftrace_filter
Will trace only the ext3 module functions.
echo '*write*:mod:ext3' > set_ftrace_notrace
Will prevent the ext3 functions with the letters 'write' in
the name from being traced.
echo '!*_allocate:mod:ext3' > set_ftrace_filter
Will remove the functions in ext3 that end with the letters
'_allocate' from the ftrace filter.
Although this patch implements the 'command' format, only the
'mod' command is supported. More commands to follow.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
ftrace_match_records does a lot of things that other features
can use. This patch breaks up ftrace_match_records and pulls
out ftrace_setup_glob and ftrace_match_record.
ftrace_setup_glob prepares a simple glob expression for use with
ftrace_match_record. ftrace_match_record compares a single record
with a glob type.
Breaking this up will allow for more features to run on individual
records.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
ftrace_match is too generic of a name. What it really does is
search all records and matches the records with the given string,
and either sets or unsets the functions to be traced depending
on if the parameter 'enable' is set or not.
This allows us to make another function called ftrace_match that
can be used to test a single record.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
To iterate over all the functions that dynamic trace knows about
it requires two for loops. One to iterate over the pages and the
other to iterate over the records within the page.
There are several duplications of these loops in ftrace.c. This
patch creates the macros do_for_each_ftrace_rec and
while_for_each_ftrace_rec to handle this logic, and removes the
duplicate code.
While making this change, I also discovered and fixed a small
bug that one of the iterations should exit the loop after it found the
record it was searching for. This used a break when it should have
used a goto, since there were two loops it needed to break out
from. No real harm was done by this bug since it would only continue
to search the other records, and the code was in a slow path anyway.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up, make set_ftrace_filter less confusing
The set_ftrace_filter shows only the functions that will be traced.
But when it is empty, it will trace all functions. This can be a bit
confusing.
This patch makes set_ftrace_filter show:
#### all functions enabled ####
When all functions will be traced, and we do not filter only a select
few.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
So it's better to use TASK_NICE here.
Signed-off-by: WANG Cong <wangcong@zeuux.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Mapping from a struct timecounter to a time returned by functions like
ktime_get_real() is implemented. This is sufficient to use this code
in a network device driver which wants to support hardware time
stamping and transformation of hardware time stamps to system time.
The interface could have been made more versatile by not depending on
a time counter, but this wasn't done to avoid writing glue code
elsewhere.
The method implemented here is the one used and analyzed under the name
"assisted PTP" in the LCI PTP paper:
http://www.linuxclustersinstitute.org/conferences/archive/2008/PDF/Ohly_92221.pdf
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
So far struct clocksource acted as the interface between time/timekeeping.c
and hardware. This patch generalizes the concept so that a similar
interface can also be used in other contexts. For that it introduces
new structures and related functions *without* touching the existing
struct clocksource.
The reasons for adding these new structures to clocksource.[ch] are
* the APIs are clearly related
* struct clocksource could be cleaned up to use the new structs
* avoids proliferation of files with similar names (timesource.h?
timecounter.h?)
As outlined in the discussion with John Stultz, this patch adds
* struct cyclecounter: stateless API to hardware which counts clock cycles
* struct timecounter: stateful utility code built on a cyclecounter which
provides a nanosecond counter
* only the function to read the nanosecond counter; deltas are used internally
and not exposed to users of timecounter
The code does no locking of the shared state. It must be called at least
as often as the cycle counter wraps around to detect these wrap arounds.
Both is the responsibility of the timecounter user.
Acked-by: John Stultz <johnstul@us.ibm.com>
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Impact: struct rq size optimization
The idle_at_tick in struct rq is only used in SMP settings
and it does not make sense to have this in the rq in an UP setup.
Signed-off-by: Henrik Austad <henrik@austad.us>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The function bts_trace_init() references a variable
bts_hotcpu_notifier which is marked
as __cpuinitdata. Thus causes section mismatch. This patch fixes it.
LD kernel/trace/built-in.o
WARNING: kernel/trace/built-in.o(.text+0xc90c): Section mismatch in
reference from the function bts_trace_init() to the variable
.cpuinit.data:bts_hotcpu_notifier
The function bts_trace_init() references
the variable __cpuinitdata bts_hotcpu_notifier.
This is often because bts_trace_init lacks a __cpuinitdata
annotation or the annotation of bts_hotcpu_notifier is wrong.
WARNING: kernel/trace/built-in.o(.text+0xc92a): Section mismatch in
reference from the function bts_trace_reset() to the variable
.cpuinit.data:bts_hotcpu_notifier
The function bts_trace_reset() references
the variable __cpuinitdata bts_hotcpu_notifier.
This is often because bts_trace_reset lacks a __cpuinitdata
annotation or the annotation of bts_hotcpu_notifier is wrong.
Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com>
Cc: markus.t.metzger@gmail.com
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cosmetic change in Kconfig menu layout
This patch was originally suggested by Peter Zijlstra, but seems it
was forgotten.
CONFIG_MMIOTRACE and CONFIG_MMIOTRACE_TEST were selectable
directly under the Kernel hacking / debugging menu in the kernel
configuration system. They were present only for x86 and x86_64.
Other tracers that use the ftrace tracing framework are in their own
sub-menu. This patch moves the mmiotrace configuration options there.
Since the Kconfig file, where the tracer menu is, is not architecture
specific, HAVE_MMIOTRACE_SUPPORT is introduced and provided only by
x86/x86_64. CONFIG_MMIOTRACE now depends on it.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: enhances lost events counting in mmiotrace
The tracing framework, or the ring buffer facility it uses, has a switch
to stop recording data. When recording is off, the trace events will be
lost. The framework does not count these, so mmiotrace has to count them
itself.
Signed-off-by: Pekka Paalanen <pq@iki.fi>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
- separate out the loop from the actual freeing logic, this wins us
two indentation levels allowing a number of followup prettifications
- turn the WARN_ON() into a more informative WARN().
- clean up the comments and the code flow some more
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The __GFP_FS annotations fail to build with CONFIG_LOCKDEP=y,
CONFIG_PROVE_LOCKING=n, ammend that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Arnd pointed out we have the stringify macro magic already in-kernel.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
re-add some of the comments that got lost in the refactoring.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now that we have nice numerical relations for the states, remove the macro
magics.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Now what its only two functions, they again look rather similar.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Generate the state bit definitions from the lockdep_states.h file.
Also, move LOCK_USED to last, so that the
USED_IN
USED_IN_READ
ENABLED
ENABLED_READ
states are nicely bit aligned -- we're going to use that property
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Introduce a header file to generate all the states from.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
s/HELD_OVER/ENABLED/g
so that its similar to the hard and soft-irq names.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
s/\(LOCKF\?_ENABLED_[^ ]*\)S\(_READ\)\?\>/\1\2/g
So that the USED_IN and ENABLED have the same names.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Here is another version, with the incremental patch rolled up, and
added reclaim context annotation to kswapd, and allocation tracing
to slab allocators (which may only ever reach the page allocator
in rare cases, so it is good to put annotations here too).
Haven't tested this version as such, but it should be getting closer
to merge worthy ;)
--
After noticing some code in mm/filemap.c accidentally perform a __GFP_FS
allocation when it should not have been, I thought it might be a good idea to
try to catch this kind of thing with lockdep.
I coded up a little idea that seems to work. Unfortunately the system has to
actually be in __GFP_FS page reclaim, then take the lock, before it will mark
it. But at least that might still be some orders of magnitude more common
(and more debuggable) than an actual deadlock condition, so we have some
improvement I hope (the concept is no less complete than discovery of a lock's
interrupt contexts).
I guess we could even do the same thing with __GFP_IO (normal reclaim), and
even GFP_NOIO locks too... but filesystems will have the most locks and fiddly
code paths, so let's start there and see how it goes.
It *seems* to work. I did a quick test.
=================================
[ INFO: inconsistent lock state ]
2.6.28-rc6-00007-ged31348-dirty #26
---------------------------------
inconsistent {in-reclaim-W} -> {ov-reclaim-W} usage.
modprobe/8526 [HC0[0]:SC0[0]:HE1:SE1] takes:
(testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
{in-reclaim-W} state was registered at:
[<ffffffff80267bdb>] __lock_acquire+0x75b/0x1a60
[<ffffffff80268f71>] lock_acquire+0x91/0xc0
[<ffffffff8070f0e1>] mutex_lock_nested+0xb1/0x310
[<ffffffffa002002b>] brd_init+0x2b/0x216 [brd]
[<ffffffff8020903b>] _stext+0x3b/0x170
[<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
[<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
[<ffffffffffffffff>] 0xffffffffffffffff
irq event stamp: 3929
hardirqs last enabled at (3929): [<ffffffff8070f2b5>] mutex_lock_nested+0x285/0x310
hardirqs last disabled at (3928): [<ffffffff8070f089>] mutex_lock_nested+0x59/0x310
softirqs last enabled at (3732): [<ffffffff8061f623>] sk_filter+0x83/0xe0
softirqs last disabled at (3730): [<ffffffff8061f5b6>] sk_filter+0x16/0xe0
other info that might help us debug this:
1 lock held by modprobe/8526:
#0: (testlock){--..}, at: [<ffffffffa0020055>] brd_init+0x55/0x216 [brd]
stack backtrace:
Pid: 8526, comm: modprobe Not tainted 2.6.28-rc6-00007-ged31348-dirty #26
Call Trace:
[<ffffffff80265483>] print_usage_bug+0x193/0x1d0
[<ffffffff80266530>] mark_lock+0xaf0/0xca0
[<ffffffff80266735>] mark_held_locks+0x55/0xc0
[<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
[<ffffffff802667ca>] trace_reclaim_fs+0x2a/0x60
[<ffffffff80285005>] __alloc_pages_internal+0x475/0x580
[<ffffffff8070f29e>] ? mutex_lock_nested+0x26e/0x310
[<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
[<ffffffffa002006a>] brd_init+0x6a/0x216 [brd]
[<ffffffffa0020000>] ? brd_init+0x0/0x216 [brd]
[<ffffffff8020903b>] _stext+0x3b/0x170
[<ffffffff8070f8b9>] ? mutex_unlock+0x9/0x10
[<ffffffff8070f83d>] ? __mutex_unlock_slowpath+0x10d/0x180
[<ffffffff802669ec>] ? trace_hardirqs_on_caller+0x12c/0x190
[<ffffffff80272ebf>] sys_init_module+0xaf/0x1e0
[<ffffffff8020c3fb>] system_call_fastpath+0x16/0x1b
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This modifies the timer code in a way to allow lockdep to detect
deadlocks resulting from a lock being taken in the timer function
as well as around the del_timer_sync() call.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
uids in namespaces other than init don't get a sysfs entry.
For those in the init namespace, while we're waiting to remove
the sysfs entry for the uid the uid is still hashed, and
alloc_uid() may re-grab that uid without getting a new
reference to the user_ns, which we've already put in free_user
before scheduling remove_user_sysfs_dir().
Reported-and-tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Convert the c/p state "power" tracer to use tracepoints. Avoids a
function call when the tracer is disabled.
Signed-off-by: Jason Baron <jbaron@redhat.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
While reviewing the manpages, I noticed I'd missed some clock vs timer sites.
Make sure that all timer functions call cpu_timer_sample_group() and not
cpu_clock_sample_group(). This ensures that we enable the process wide timer
in time, and therefore pay the O(n) thread group cost from the syscall.
Not doing it here, will result in the first jiffy tick after setting the timer
doing this, resulting in a very expensive tick (but only once) and a delay in
actually starting the timer.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
request_irq() calls into proc code via __setup_irq() which is not safe
in an atomic context, so request_irq() can itself use the more
reliable GFP_KERNEL allocation for the action descriptor.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: clean up
While reviewing the ring buffer code, I thougth I saw a bug with
if (!__raw_spin_trylock(&cpu_buffer->lock))
goto out_unlock;
But I forgot that we use a variable "lock_taken" that is set if
the spinlock is taken, and only unlock it if that variable is set.
To avoid further confusion from other reviewers, this patch
renames the label out_unlock with out_reset, which is the more
appropriate name.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
CONFIG_SOFTLOCKUP=y || CONFIG_DETECT_HUNG_TASKS=y is now the only user
of the 'one' constant in kernel/sysctl.c. Move it to the softlockup
block of constants.
This fixes a GCC warning.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I enabled all cgroup subsystems when compiling kernel, and then:
# mount -t cgroup -o net_cls xxx /mnt
# mkdir /mnt/0
This showed up immediately:
BUG: MAX_LOCKDEP_SUBCLASSES too low!
turning off the locking correctness validator.
It's caused by the cgroup hierarchy lock:
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
if (ss->root == root)
mutex_lock_nested(&ss->hierarchy_mutex, i);
}
Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but
MAX_LOCKDEP_SUBCLASSES is 8.
This patch uses different lockdep keys for different subsystems.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to pass an unsigned long as the minimum, because it gets casted
to an unsigned long in the sysctl handler. If we pass an int, we'll
access four more bytes on 64bit arches, resulting in a random minimum
value.
[rientjes@google.com: fix type of `old_bytes']
Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Catalin noticed that (38d47c1b70: futex: rely on get_user_pages() for
shared futexes) caused an mm_struct leak.
Some tracing with the function graph tracer quickly pointed out that
futex_wait() has exit paths with unbalanced reference counts.
This regression was discovered by kmemleak.
Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
timers: fix TIMER_ABSTIME for process wide cpu timers
timers: split process wide cpu clocks/timers, fix
x86: clean up hpet timer reinit
timers: split process wide cpu clocks/timers, remove spurious warning
timers: split process wide cpu clocks/timers
signal: re-add dead task accumulation stats.
x86: fix hpet timer reinit for x86_64
sched: fix nohz load balancer on cpu offline
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
ptrace, x86: fix the usage of ptrace_fork()
i8327: fix outb() parameter order
x86: fix math_emu register frame access
x86: math_emu info cleanup
x86: include correct %gs in a.out core dump
x86, vmi: put a missing paravirt_release_pmd in pgd_dtor
x86: find nr_irqs_gsi with mp_ioapic_routing
x86: add clflush before monitor for Intel 7400 series
x86: disable intel_iommu support by default
x86: don't apply __supported_pte_mask to non-present ptes
x86: fix grammar in user-visible BIOS warning
x86/Kconfig.cpu: make Kconfig help readable in the console
x86, 64-bit: print DMI info in the oops trace
Intel reported a 10% regression (mysql+sysbench) on a 16-way machine
with these patches:
1596e29: sched: symmetric sync vs avg_overlap
d942fb6: sched: fix sync wakeups
Revert them.
Reported-by: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Bisected-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The POSIX timer interface allows for absolute time expiry values through the
TIMER_ABSTIME flag, therefore we have to synchronize the timer to the clock
every time we start it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
To decrease the chance of a missed enable, always enable the timer when we
sample it, we'll always disable it when we find that there are no active timers
in the jiffy tick.
This fixes a flood of warnings reported by Mike Galbraith.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Add the missing pair tracing_{start,stop}_record_cmdline() to record well
the cmdline associated with pid.
Changes in v2:
- fix a build error, the sched_switch tracer is needed to record the
cmdline.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When we check if a task has been switched out since the last scan, we might
have a race condition on the following scenario:
- the task is freshly created and scheduled
- it puts its state to TASK_UNINTERRUPTIBLE and is not yet switched out
- check_hung_task() scans this task and will report a false positive because
t->nvcsw + t->nivcsw == t->last_switch_count == 0
Add a check for such cases.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I noticed by pure accident we have ptrace_fork() and friends. This was
added by "x86, bts: add fork and exit handling", commit
bf53de907d.
I can't test this, ds_request_bts() returns -EOPNOTSUPP, but I strongly
believe this needs the fix. I think something like this program
int main(void)
{
int pid = fork();
if (!pid) {
ptrace(PTRACE_TRACEME, 0, NULL, NULL);
kill(getpid(), SIGSTOP);
fork();
} else {
struct ptrace_bts_config bts = {
.flags = PTRACE_BTS_O_ALLOC,
.size = 4 * 4096,
};
wait(NULL);
ptrace(PTRACE_SETOPTIONS, pid, NULL, PTRACE_O_TRACEFORK);
ptrace(PTRACE_BTS_CONFIG, pid, &bts, sizeof(bts));
ptrace(PTRACE_CONT, pid, NULL, NULL);
sleep(1);
}
return 0;
}
should crash the kernel.
If the task is traced by its natural parent ptrace_reparented() returns 0
but we should clear ->btsxxx anyway.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Andrew had some suggestions for the latencytop file; this patch takes care
of most of these:
* Add documentation
* Turn account_scheduler_latency into an inline function
* Don't report negative values to userspace
* Make the file operations struct const
* Fix a few checkpatch.pl warnings
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Fix these sparse warnings:
kernel/trace/ring_buffer.c:70:37: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:84:39: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:96:43: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2475:13: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2475:13: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2478:42: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2478:42: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2500:40: warning: incorrect type in argument 3 (different signedness)
kernel/trace/ring_buffer.c:2505:44: warning: incorrect type in argument 2 (different signedness)
kernel/trace/ring_buffer.c:2507:46: warning: incorrect type in argument 2 (different signedness)
kernel/trace/trace.c:2130:40: warning: incorrect type in argument 3 (different signedness)
kernel/trace/trace.c:2280:40: warning: incorrect type in argument 3 (different signedness)
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: make global variables and a global function static
The function '__trace_userstack' does not seem to have a caller, so it
is commented out.
Fix this sparse warnings:
kernel/trace/trace.c:82:5: warning: symbol 'tracing_disabled' was not declared. Should it be static?
kernel/trace/trace.c:600:10: warning: symbol 'trace_record_cmdline_disabled' was not declared. Should it be static?
kernel/trace/trace.c:957:6: warning: symbol '__trace_userstack' was not declared. Should it be static?
kernel/trace/trace.c:1694:5: warning: symbol 'tracing_release' was not declared. Should it be static?
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This patch is to make the function return early on failure, and give
correct return value on success.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
The C99 specification states in section 6.11.5:
The placement of a storage-class specifier other than at the beginning
of the declaration specifiers in a declaration is an obsolescent
feature.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: change API and init bpage when copy
ring_buffer_read_page()/rb_remove_entries() may be called for
a partially consumed page.
Add a parameter for rb_remove_entries() and make it update
cpu_buffer->entries correctly for partially consumed pages.
ring_buffer_read_page() now returns the offset to the next event.
Init the bpage's time_stamp when return value is 0.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: Fix bug
I found several very very curious line.
It's so curious that it may be brought by typing mistake.
When (cpu_buffer->reader_page == cpu_buffer->commit_page):
1) We haven't copied it for bpage is changed:
bpage = cpu_buffer->reader_page->page;
memcpy(bpage->data, cpu_buffer->reader_page->page->data + read ... )
2) We need update cpu_buffer->reader_page->read, but
"cpu_buffer->reader_page += read;" is not right.
[
This bug was a typo. The commit->reader_page is a page pointer
and not an index into the page. The line should have been
commit->reader_page->read += read. The other changes
by Lai are nice clean ups to the code. - SDR
]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix broken /proc/profile on UP machines
Commit c309b917ca "cpumask: convert
kernel/profile.c" broke profiling. prof_cpu_mask was previously
initialized to CPU_MASK_ALL, but left uninitialized in that commit.
We need to copy cpu_possible_mask (cpu_online_mask is not enough).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: no default -fno-stack-protector if stackp is enabled, cleanup
Stackprotector make rules had the following problems.
* cc support test and warning are scattered across makefile and
kernel/panic.c.
* -fno-stack-protector was always added regardless of configuration.
Update such that cc support test and warning are contained in makefile
and -fno-stack-protector is added iff stackp is turned off. While at
it, prepare for 32bit support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
ELF core dump is used for both user land core dump and kernel crash
dump. Depending on architecture, register might need to be accessed
differently for userland and kernel. Allow architectures to define
ELF_CORE_COPY_KERNEL_REGS() and use different operation for kernel
register dump.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Ingo Molnar suggested a series of clean ups for the splice code.
This patch implements those suggestions.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
This moves the pipe waiting code from tracing_read_pipe() into
tracing_wait_pipe(), which is useful to implement other fops, like
splice_read.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Added and implemented tracing_pipe_fops->splice_read(). This allows
userspace programs to get tracing data more efficiently.
Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
When one cats the trace file, the leaf functions are printed without brackets:
function();
whereas in the trace_pipe file we'll see the following:
function() {
}
This is because the ring_buffer handling is not the same between those two files.
On the trace file, when an entry is printed, the iterator advanced and then we can
check the next entry.
There is no iterator with trace_pipe, the current entry to print has been peeked
and not consumed. So checking the next entry will still return the current one while
we don't consume it.
This patch introduces a new value for the output callbacks to ask the tracing
core to not consume the current entry after printing it.
We need it because we will have to consume the current entry ourself to check
the next one.
Now the trace_pipe is able to handle well the leaf functions.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: build fix
The BLK_DEV_IO_TRACE entry used to be in block/Kconfig - which
file itself was dependent on CONFIG_BLOCK. But now the entry is
in kernel/trace/Kconfig - which is present even on !CONFIG_BLOCK.
So add a 'depends on BLOCK' to BLK_DEV_IO_TRACE.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: saves sizeof(long) bytes per task_struct
By guaranteeing that sysctl_hung_task_timeout_secs have elapsed between
tasklist scans we can avoid using timestamps.
Signed-off-by: Mandeep Singh Baines <msb@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: simplification
Instead of requiring that plugins have the sequence:
my_tracer_stop(my_trace_array);
unregister_tracer(my_tracer);
it should be possible just do a:
unregister_tracer(my_tracer);
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
When the function graph tracer picks a return address, it ensures this address
is really a kernel text one by calling __kernel_text_address()
Actually this path has never been taken.Its role was more likely to debug the tracer
on the beginning of its development but this function is wasteful since it is called
for every traced function.
The fault check is already sufficient.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: cleanup
Move the power tracer headers to trace/power.h to keep ftrace.h and power bits
more easy to maintain as separated topics.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Making it more easy to do a basic regression test for this tracer.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
While being at it make every occurrence of 'do_irq_select_affinity'
have the same signature in terms of signedness of the first argument.
Fix this sparse warning:
kernel/irq/manage.c:112:5: warning: symbol 'do_irq_select_affinity' was not declared. Should it be static?
Also rename do_irq_select_affinity() to setup_affinity() - shorter name
and clearer naming.
Signed-off-by: Hannes Eder <hannes@hanneseder.net>
Acked-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Simplify and make init_kstat_irqs etc more type proof, suggested by
Andrew.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: get correct kstat_irqs [/proc/interrupts] for msi/msi-x etc
need to call clear_kstat_irqs(), so when we reuse that irq_desc,
we get correct kstat in /proc/interrupts.
This makes /proc/interrupts not have <NULL> entries.
Don't need to worry about arch that doesn't support genirq, because they
will not call dynamic_irq_cleanup().
v2: simplify and make clear_kstat_irqs more robust
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
list.h provides a dedicated primitive for
"list_del followed by list_add_tail"... list_move_tail.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Rename the async_*_special() functions to async_*_domain(), which
describes the purpose of these functions much better.
[Broke up long lines to silence checkpatch]
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Add some kerneldoc to the async interface.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
If we fail to create the manager thread, fall back to non-fastboot.
If we fail to create an async thread, try again after waiting for
a bit.
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
async_schedule() should pass in async_running as the running
list, and run_one_entry() should put the entry to be run on
the provided running list instead of always on the generic one.
Reported-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Impact: clean up
Fixed several typos in the comments.
Signed-off-by: Wenji Huang <wenji.huang@oracle.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: clean up
Now that a generic in_nmi is available, this patch removes the
special code in the ring_buffer and implements the in_nmi generic
version instead.
With this change, I was also able to rename the "arch_ftrace_nmi_enter"
back to "ftrace_nmi_enter" and remove the code from the ring buffer.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: prevent deadlock in NMI
The ring buffers are not yet totally lockless with writing to
the buffer. When a writer crosses a page, it grabs a per cpu spinlock
to protect against a reader. The spinlocks taken by a writer are not
to protect against other writers, since a writer can only write to
its own per cpu buffer. The spinlocks protect against readers that
can touch any cpu buffer. The writers are made to be reentrant
with the spinlocks disabling interrupts.
The problem arises when an NMI writes to the buffer, and that write
crosses a page boundary. If it grabs a spinlock, it can be racing
with another writer (since disabling interrupts does not protect
against NMIs) or with a reader on the same CPU. Luckily, most of the
users are not reentrant and protects against this issue. But if a
user of the ring buffer becomes reentrant (which is what the ring
buffers do allow), if the NMI also writes to the ring buffer then
we risk the chance of a deadlock.
This patch moves the ftrace_nmi_enter called by nmi_enter() to the
ring buffer code. It replaces the current ftrace_nmi_enter that is
used by arch specific code to arch_ftrace_nmi_enter and updates
the Kconfig to handle it.
When an NMI is called, it will set a per cpu variable in the ring buffer
code and will clear it when the NMI exits. If a write to the ring buffer
crosses page boundaries inside an NMI, a trylock is used on the spin
lock instead. If the spinlock fails to be acquired, then the entry
is discarded.
This bug appeared in the ftrace work in the RT tree, where event tracing
is reentrant. This workaround solved the deadlocks that appeared there.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Impact: fix to prevent developers from using entry->cpu
With the new ring buffer infrastructure, the cpu for the entry is
implicit with which CPU buffer it is on.
The original code use to record the current cpu into the generic
entry header, which can be retrieved by entry->cpu. When the
ring buffer was introduced, the users were convert to use the
the cpu number of which cpu ring buffer was in use (this was passed
to the tracers by the iterator: iter->cpu).
Unfortunately, the cpu item in the entry structure was never removed.
This allowed for developers to use it instead of the proper iter->cpu,
unknowingly, using an uninitialized variable. This was not the fault
of the developers, since it would seem like the logical place to
retrieve the cpu identifier.
This patch removes the cpu item from the entry structure and fixes
all the users that should have been using iter->cpu.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
I happened to forked lots of processes, and hit NULL pointer dereference.
It is because in copy_process() after checking max_threads, 0 is returned
but not -EAGAIN.
The bug is introduced by "CRED: Detach the credentials from task_struct"
(commit f1752eec61).
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Impact: cleanup
To make it easy for ftrace plugin writers, as this was open coded in
the existing plugins
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Impact: new API
These new functions do what previously was being open coded, reducing
the number of details ftrace plugin writers have to worry about.
It also standardizes the handling of stacktrace, userstacktrace and
other trace options we may introduce in the future.
With this patch, for instance, the blk tracer (and some others already
in the tree) can use the "userstacktrace" /d/tracing/trace_options
facility.
$ codiff /tmp/vmlinux.before /tmp/vmlinux.after
linux-2.6-tip/kernel/trace/trace.c:
trace_vprintk | -5
trace_graph_return | -22
trace_graph_entry | -26
trace_function | -45
__ftrace_trace_stack | -27
ftrace_trace_userstack | -29
tracing_sched_switch_trace | -66
tracing_stop | +1
trace_seq_to_user | -1
ftrace_trace_special | -63
ftrace_special | +1
tracing_sched_wakeup_trace | -70
tracing_reset_online_cpus | -1
13 functions changed, 2 bytes added, 355 bytes removed, diff: -353
linux-2.6-tip/block/blktrace.c:
__blk_add_trace | -58
1 function changed, 58 bytes removed, diff: -58
linux-2.6-tip/kernel/trace/trace.c:
trace_buffer_lock_reserve | +88
trace_buffer_unlock_commit | +86
2 functions changed, 174 bytes added, diff: +174
/tmp/vmlinux.after:
16 functions changed, 176 bytes added, 413 bytes removed, diff: -237
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Frédéric Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
