alloc_mayday_mask() was using alloc_cpumask_var() making
gcwq->mayday_mask contain garbage after initialization on
CONFIG_CPUMASK_OFFSTACK=y configurations. This combined with the
previously fixed GCWQ_DISASSOCIATED initialization bug could make
rescuers fall into infinite loop trying to bind to an offline cpu.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: CAI Qian <caiqian@redhat.com>
init_workqueues() incorrectly marks workqueues for all possible CPUs
associated. Combined with mayday_mask initialization bug, this can
make rescuers keep trying to bind to an offline gcwq indefinitely.
Fix init_workqueues() such that only online CPUs have their gcwqs have
GCWQ_DISASSOCIATED cleared.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: CAI Qian <caiqian@redhat.com>
Fix the pm_qos_add_request() kerneldoc comment that doesn't reflect
the behavior of the function after the last PM QoS update.
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf, x86, Pentium4: Clear the P4_CCCR_FORCE_OVF flag
tracing/trace_stack: Fix stack trace on ppc64
* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states
sched: Fix rq->clock synchronization when migrating tasks
cwq->nr_active is used to keep track of how many work items are active
for the cpu workqueue, where 'active' is defined as either pending on
global worklist or executing. This is used to implement the
max_active limit and workqueue freezing. If a work item is queued
after nr_active has already reached max_active, the work item doesn't
increment nr_active and is put on the delayed queue and gets activated
later as previous active work items retire.
try_to_grab_pending() which is used in the cancellation path
unconditionally decremented nr_active whether the work item being
cancelled is currently active or delayed, so cancelling a delayed work
item makes nr_active underflow. This breaks max_active enforcement
and triggers BUG_ON() in destroy_workqueue() later on.
This patch fixes this bug by adding a flag WORK_STRUCT_DELAYED, which
is set while a work item in on the delayed list and making
try_to_grab_pending() decrement nr_active iff the work item is
currently active.
The addition of the flag enlarges cwq alignment to 256 bytes which is
getting a bit too large. It's scheduled to be reduced back to 128
bytes by merging WORK_STRUCT_PENDING and WORK_STRUCT_CWQ in the next
devel cycle.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Johannes Berg <johannes@sipsolutions.net>
sparse spotted that the kzalloc() in pm_qos_power_open() in the
current Linus' git tree had its parameters swapped. Fix this.
Signed-off-by: David Alan Gilbert <linux@treblig.org>
Acked-by: mark gross <markgross@thegnar.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Now that the worklist is global, having works pending after wq
destruction can easily lead to oops and destroy_workqueue() have
several BUG_ON()s to catch these cases. Unfortunately, BUG_ON()
doesn't tell much about how the work became pending after the final
flush_workqueue().
This patch adds WQ_DYING which is set before the final flush begins.
If a work is requested to be queued on a dying workqueue,
WARN_ON_ONCE() is triggered and the request is ignored. This clearly
indicates which caller is trying to queue a work on a dying workqueue
and keeps the system working in most cases.
Locking rule comment is updated such that the 'I' rule includes
modifying the field from destruction path.
Signed-off-by: Tejun Heo <tj@kernel.org>
worker_maybe_bind_and_lock() actually grabs gcwq->lock but was missing proper
annotation. Add it. So this patch will remove following sparse warnings:
kernel/workqueue.c:1214:13: warning: context imbalance in 'worker_maybe_bind_and_lock' - wrong count at exit
arch/x86/include/asm/irqflags.h:44:9: warning: context imbalance in 'worker_rebind_fn' - unexpected unlock
kernel/workqueue.c:1991:17: warning: context imbalance in 'rescuer_thread' - unexpected unlock
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Some of internal functions called within gcwq->lock context releases and
regrabs the lock but were missing proper annotations. Add it.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
There is a scalability issue for current implementation of optimistic
mutex spin in the kernel. It is found on a 8 node 64 core Nehalem-EX
system (HT mode).
The intention of the optimistic mutex spin is to busy wait and spin on a
mutex if the owner of the mutex is running, in the hope that the mutex
will be released soon and be acquired, without the thread trying to
acquire mutex going to sleep. However, when we have a large number of
threads, contending for the mutex, we could have the mutex grabbed by
other thread, and then another ……, and we will keep spinning, wasting cpu
cycles and adding to the contention. One possible fix is to quit
spinning and put the current thread on wait-list if mutex lock switch to
a new owner while we spin, indicating heavy contention (see the patch
included).
I did some testing on a 8 socket Nehalem-EX system with a total of 64
cores. Using Ingo's test-mutex program that creates/delete files with 256
threads (http://lkml.org/lkml/2006/1/8/50) , I see the following speed up
after putting in the mutex spin fix:
./mutex-test V 256 10
Ops/sec
2.6.34 62864
With fix 197200
Repeating the test with Aim7 fserver workload, again there is a speed up
with the fix:
Jobs/min
2.6.34 91657
With fix 149325
To look at the impact on the distribution of mutex acquisition time, I
collected the mutex acquisition time on Aim7 fserver workload with some
instrumentation. The average acquisition time is reduced by 48% and
number of contentions reduced by 32%.
#contentions Time to acquire mutex (cycles)
2.6.34 72973 44765791
With fix 49210 23067129
The histogram of mutex acquisition time is listed below. The acquisition
time is in 2^bin cycles. We see that without the fix, the acquisition
time is mostly around 2^26 cycles. With the fix, we the distribution get
spread out a lot more towards the lower cycles, starting from 2^13.
However, there is an increase of the tail distribution with the fix at
2^28 and 2^29 cycles. It seems a small price to pay for the reduced
average acquisition time and also getting the cpu to do useful work.
Mutex acquisition time distribution (acq time = 2^bin cycles):
2.6.34 With Fix
bin #occurrence % #occurrence %
11 2 0.00% 120 0.24%
12 10 0.01% 790 1.61%
13 14 0.02% 2058 4.18%
14 86 0.12% 3378 6.86%
15 393 0.54% 4831 9.82%
16 710 0.97% 4893 9.94%
17 815 1.12% 4667 9.48%
18 790 1.08% 5147 10.46%
19 580 0.80% 6250 12.70%
20 429 0.59% 6870 13.96%
21 311 0.43% 1809 3.68%
22 255 0.35% 2305 4.68%
23 317 0.44% 916 1.86%
24 610 0.84% 233 0.47%
25 3128 4.29% 95 0.19%
26 63902 87.69% 122 0.25%
27 619 0.85% 286 0.58%
28 0 0.00% 3536 7.19%
29 0 0.00% 903 1.83%
30 0 0.00% 0 0.00%
I've done similar experiments with 2.6.35 kernel on smaller boxes as
well. One is on a dual-socket Westmere box (12 cores total, with HT).
Another experiment is on an old dual-socket Core 2 box (4 cores total, no
HT)
On the 12-core Westmere box, I see a 250% increase for Ingo's mutex-test
program with my mutex patch but no significant difference in aim7's
fserver workload.
On the 4-core Core 2 box, I see the difference with the patch for both
mutex-test and aim7 fserver are negligible.
So far, it seems like the patch has not caused regression on smaller
systems.
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: <stable@kernel.org> # .35.x
LKML-Reference: <1282168827.9542.72.camel@schen9-DESK>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Stephane reported that when the machine locks up, the regular ticks,
which are responsible to resetting the throttle count, stop too.
Hence the NMI watchdog can end up being throttled before it reports on
the locked up state, and we end up being sad..
Cure this by having the watchdog overflow reset its own throttle count.
Reported-by: Stephane Eranian <eranian@google.com>
Tested-by: Stephane Eranian <eranian@google.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1282215916.1926.4696.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
With the introduction of the new unified work queue thread pools,
we lost one feature: It's no longer possible to know which worker
is causing the CPU to wake out of idle. The result is that PowerTOP
now reports a lot of "kworker/a:b" instead of more readable results.
This patch adds a pair of tracepoints to the new workqueue code,
similar in style to the timer/hrtimer tracepoints.
With this pair of tracepoints, the next PowerTOP can correctly
report which work item caused the wakeup (and how long it took):
Interrupt (43) i915 time 3.51ms wakeups 141
Work ieee80211_iface_work time 0.81ms wakeups 29
Work do_dbs_timer time 0.55ms wakeups 24
Process Xorg time 21.36ms wakeups 4
Timer sched_rt_period_timer time 0.01ms wakeups 1
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's a really simple list, and several of the users want to go backwards
in it to find the previous vma. So rather than have to look up the
previous entry with 'find_vma_prev()' or something similar, just make it
doubly linked instead.
Tested-by: Ian Campbell <ijc@hellion.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sysrq operations do not accept tty argument anymore so no need to pass
it to us.
[Stephen Rothwell <sfr@canb.auug.org.au>: fix build breakage in drm code
caused by sysrq using bool but not including linux/types.h]
[Sachin Sant <sachinp@in.ibm.com>: fix build breakage in s390 keyboadr
driver]
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
kfifo_skip() is currently broken, due to the missing of the internal
helper function. Add it.
Signed-off-by: Andrea Righi <arighi@develer.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
sched_fork() -- we do task placement in ->task_fork_fair() ensure we
update_rq_clock() so we work with current time. We leave the vruntime
in relative state, so the time delay until wake_up_new_task() doesn't
matter.
wake_up_new_task() -- Since task_fork_fair() left p->vruntime in
relative state we can safely migrate, the activate_task() on the
remote rq will call update_rq_clock() and causes the clock to be
synced (enough).
Tested-by: Jack Daniel <wanders.thirst@gmail.com>
Tested-by: Philby John <pjohn@mvista.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1281002322.1923.1708.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Noone is using tty argument so let's get rid of it.
Acked-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Acked-by: Jason Wessel <jason.wessel@windriver.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
fs: brlock vfsmount_lock
fs: scale files_lock
lglock: introduce special lglock and brlock spin locks
tty: fix fu_list abuse
fs: cleanup files_lock locking
fs: remove extra lookup in __lookup_hash
fs: fs_struct rwlock to spinlock
apparmor: use task path helpers
fs: dentry allocation consolidation
fs: fix do_lookup false negative
mbcache: Limit the maximum number of cache entries
hostfs ->follow_link() braino
hostfs: dumb (and usually harmless) tpyo - strncpy instead of strlcpy
remove SWRITE* I/O types
kill BH_Ordered flag
vfs: update ctime when changing the file's permission by setfacl
cramfs: only unlock new inodes
fix reiserfs_evict_inode end_writeback second call
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
perf tools: Fix build on POSIX shells
latencytop: Fix kconfig dependency warnings
perf annotate tui: Fix exit and RIGHT keys handling
tracing: Sanitize value returned from write(trace_marker, "...", len)
tracing/events: Convert format output to seq_file
tracing: Extend recordmcount to better support Blackfin mcount
tracing: Fix ring_buffer_read_page reading out of page boundary
tracing: Fix an unallocated memory access in function_graph
fs: fs_struct rwlock to spinlock
struct fs_struct.lock is an rwlock with the read-side used to protect root and
pwd members while taking references to them. Taking a reference to a path
typically requires just 2 atomic ops, so the critical section is very small.
Parallel read-side operations would have cacheline contention on the lock, the
dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
real parallelism increase.
Replace it with a spinlock to avoid one or two atomic operations in typical
path lookup fastpath.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
vt,console,kdb: preserve console_blanked while in kdb
vt: fix regression warnings from KMS merge
arm,kgdb: fix GDB_MAX_REGS no longer used
kgdb: add missing __percpu markup in arch/x86/kernel/kgdb.c
kdb: fix compile error without CONFIG_KALLSYMS
Using a program like the following:
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
int main() {
id_t id;
siginfo_t infop;
pid_t res;
id = fork();
if (id == 0) { sleep(1); exit(0); }
kill(id, SIGSTOP);
alarm(1);
waitid(P_PID, id, &infop, WCONTINUED);
return 0;
}
to call waitid() on a stopped process results in access to the child task's
credentials without the RCU read lock being held - which may be replaced in the
meantime - eliciting the following warning:
===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
kernel/exit.c:1460 invoked rcu_dereference_check() without protection!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
2 locks held by waitid02/22252:
#0: (tasklist_lock){.?.?..}, at: [<ffffffff81061ce5>] do_wait+0xc5/0x310
#1: (&(&sighand->siglock)->rlock){-.-...}, at: [<ffffffff810611da>]
wait_consider_task+0x19a/0xbe0
stack backtrace:
Pid: 22252, comm: waitid02 Not tainted 2.6.35-323cd+ #3
Call Trace:
[<ffffffff81095da4>] lockdep_rcu_dereference+0xa4/0xc0
[<ffffffff81061b31>] wait_consider_task+0xaf1/0xbe0
[<ffffffff81061d15>] do_wait+0xf5/0x310
[<ffffffff810620b6>] sys_waitid+0x86/0x1f0
[<ffffffff8105fce0>] ? child_wait_callback+0x0/0x70
[<ffffffff81003282>] system_call_fastpath+0x16/0x1b
This is fixed by holding the RCU read lock in wait_task_continued() to ensure
that the task's current credentials aren't destroyed between us reading the
cred pointer and us reading the UID from those credentials.
Furthermore, protect wait_task_stopped() in the same way.
We don't need to keep holding the RCU read lock once we've read the UID from
the credentials as holding the RCU read lock doesn't stop the target task from
changing its creds under us - so the credentials may be outdated immediately
after we've read the pointer, lock or no lock.
Signed-off-by: Daniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make do_execve() take a const filename pointer so that kernel_execve() compiles
correctly on ARM:
arch/arm/kernel/sys_arm.c:88: warning: passing argument 1 of 'do_execve' discards qualifiers from pointer target type
This also requires the argv and envp arguments to be consted twice, once for
the pointer array and once for the strings the array points to. This is
because do_execve() passes a pointer to the filename (now const) to
copy_strings_kernel(). A simpler alternative would be to cast the filename
pointer in do_execve() when it's passed to copy_strings_kernel().
do_execve() may not change any of the strings it is passed as part of the argv
or envp lists as they are some of them in .rodata, so marking these strings as
const should be fine.
Further kernel_execve() and sys_execve() need to be changed to match.
This has been test built on x86_64, frv, arm and mips.
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If CONFIG_KGDB_KDB is set and CONFIG_KALLSYMS is not set the kernel
will fail to build with the error:
kernel/built-in.o: In function `kallsyms_symbol_next':
kernel/debug/kdb/kdb_support.c:237: undefined reference to `kdb_walk_kallsyms'
kernel/built-in.o: In function `kallsyms_symbol_complete':
kernel/debug/kdb/kdb_support.c:193: undefined reference to `kdb_walk_kallsyms'
The kdb_walk_kallsyms needs a #ifdef proper header to match the C
implementation. This patch also fixes the compiler warnings in
kdb_support.c when compiling without CONFIG_KALLSYMS set. The
compiler warnings are a result of the kallsyms_lookup() macro not
initializing the two of the pass by reference variables.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Reported-by: Michal Simek <monstr@monstr.eu>
wq->rescuer is not freed when wq is destroyed, leads a memory leak
then. This patch also remove a redundant line.
Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Early 4.3 versions of gcc apparently aggressively optimize the raw
time accumulation loop, replacing it with a divide.
On 32bit systems, this causes the following link errors:
undefined reference to `__umoddi3'
undefined reference to `__udivdi3'
The gcc issue has been fixed in 4.4 and greater.
This patch replaces the accumulation loop with a do_div, as suggested
by Linus.
Signed-off-by: John Stultz <johnstul@us.ibm.com>
CC: Jason Wessel <jason.wessel@windriver.com>
CC: Larry Finger <Larry.Finger@lwfinger.net>
CC: Ingo Molnar <mingo@elte.hu>
CC: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This reverts commit 3bcf3860a4 (and the
accompanying commit c1e5c95402 "vfs/fsnotify: fsnotify_close can delay
the final work in fput" that was a horribly ugly hack to make it work at
all).
The 'struct file' approach not only causes that disgusting hack, it
somehow breaks pulseaudio, probably due to some other subtlety with
f_count handling.
Fix up various conflicts due to later fsnotify work.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Two new events were added that broke the current format output.
Both from the SCSI system: scsi_dispatch_cmd_done and scsi_dispatch_cmd_timeout
The reason is that their print_fmt exceeded a page size. Since the output
of the format used simple_read_from_buffer and trace_seq, it was limited
to a page size in output.
This patch converts the printing of the format of an event into seq_file,
which allows greater than a page size to be shown.
I diffed all event formats comparing the output with and without this
patch. All matched except for the above two, which showed just:
FORMAT TOO BIG
without this patch, but now properly displays the output with this patch.
v2: Remove updating *pos in seq start function.
[ Thanks to Li Zefan for pointing that out ]
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com>
Cc: James Bottomley <James.Bottomley@suse.de>
Cc: Tomohiro Kusumi <kusumi.tomohiro@jp.fujitsu.com>
Cc: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'params' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-for-linus: (22 commits)
param: don't deref arg in __same_type() checks
param: update drivers/acpi/debug.c to new scheme
param: use module_param in drivers/message/fusion/mptbase.c
ide: use module_param_named rather than module_param_call
param: update drivers/char/ipmi/ipmi_watchdog.c to new scheme
param: lock if_sdio's lbs_helper_name and lbs_fw_name against sysfs changes.
param: lock myri10ge_fw_name against sysfs changes.
param: simple locking for sysfs-writable charp parameters
param: remove unnecessary writable charp
param: add kerneldoc to moduleparam.h
param: locking for kernel parameters
param: make param sections const.
param: use free hook for charp (fix leak of charp parameters)
param: add a free hook to kernel_param_ops.
param: silence .init.text references from param ops
Add param ops struct for hvc_iucv driver.
nfs: update for module_param_named API change
AppArmor: update for module_param_named API change
param: use ops in struct kernel_param, rather than get and set fns directly
param: move the EXPORT_SYMBOL to after the definitions.
...
The tv_nsec is a long and when added to the shifted interval it can wrap
and become negative which later causes looping problems in the
getrawmonotonic(). The edge case occurs when the system has slept for
a short period of time of ~2 seconds.
A trace printk of the values in this patch illustrate the problem:
ftrace time stamp: log
43.716079: logarithmic_accumulation: raw: 3d0913 tv_nsec d687faa
43.718513: logarithmic_accumulation: raw: 3d0913 tv_nsec da588bd
43.722161: logarithmic_accumulation: raw: 3d0913 tv_nsec de291d0
46.349925: logarithmic_accumulation: raw: 7a122600 tv_nsec e1f9ae3
46.349930: logarithmic_accumulation: raw: 1e848980 tv_nsec 8831c0e3
The kernel starts looping at 46.349925 in the getrawmonotonic() due to
the negative value from adding the raw value to tv_nsec.
A simple solution is to accumulate into a u64, and then normalize it
to a timespec_t.
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
[ Reworked variable names and simplified some of the code. - John ]
Signed-off-by: John Stultz <johnstul@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a dummy printk function for the maintenance of unused printks through gcc
format checking, and also so that side-effect checking is maintained too.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Secure discard is the same as discard except that all copies of the
discarded sectors (perhaps created by garbage collection) must also be
erased.
Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kyungmin Park <kmpark@infradead.org>
Cc: Madhusudhan Chikkature <madhu.cr@ti.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current kfifo scatterlist implementation will not work with chained
scatterlists. It assumes that struct scatterlist arrays are allocated
contiguously, which is not the case when chained scatterlists (struct
sg_table) are in use.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
isofs: Fix lseek() to position beyond 4 GB
vfs: remove unused MNT_STRICTATIME
vfs: show unreachable paths in getcwd and proc
vfs: only add " (deleted)" where necessary
vfs: add prepend_path() helper
vfs: __d_path: dont prepend the name of the root dentry
ia64: perfmon: add d_dname method
vfs: add helpers to get root and pwd
cachefiles: use path_get instead of lone dget
fs/sysv/super.c: add support for non-PDP11 v7 filesystems
V7: Adjust sanity checks for some volumes
Add v7 alias
v9fs: fixup for inode_setattr being removed
Manual merge to take Al's version of the fs/sysv/super.c file: it merged
cleanly, but Al had removed an unnecessary header include, so his side
was better.
Simply replace the whole kfifo.c and kfifo.h files with the new generic
version and fix the kerneldoc API template file.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add the new version of the kfifo API files kfifo.c and kfifo.h.
Signed-off-by: Stefani Seibold <stefani@seibold.net>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
copy_to/from_user() returns the number of bytes remaining to be copied.
It never returns a negative value. The correct return code is -EFAULT and
not -EIO.
All the callers check for non-zero returns so that's Ok, but the return
code is passed to the user so we should fix this.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Simon Kagstrom <simon.kagstrom@netinsight.net>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are missing the oops end marker for the exception based WARN implementation
in lib/bug.c. This is useful for logfile analysis tools.
Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
To keep panic_timeout accuracy when running under a hypervisor, the
current implementation only spins on long time (1 second) calls to mdelay.
That brings a good effect, but the problem is the keyboard LEDs don't
blink at all on that situation.
This patch changes to call to panic_blink_enter() between every mdelay and
keeps blinking in spite of long spin timer mode.
The time to call to mdelay is now 100ms. Even this change will keep
panic_timeout accuracy enough when running under a hypervisor.
Signed-off-by: TAMUKI Shoichi <tamuki@linet.gr.jp>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Russell King <linux@arm.linux.org.uk>
Acked-by: Dmitry Torokhov <dtor@mail.ru>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alloc_pidmap() calculates max_scan so that if the initial offset != 0 we
inspect the first map->page twice. This is correct, we want to find the
unused bits < offset in this bitmap block. Add the comment.
But it doesn't make any sense to stop the find_next_offset() loop when we
are looking into this map->page for the second time. We have already
already checked the bits >= offset during the first attempt, it is fine to
do this again, no matter if we succeed this time or not.
Remove this hard-to-understand code. It optimizes the very unlikely case
when we are going to fail, but slows down the more likely case.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Salman Qazi <sqazi@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A program that repeatedly forks and waits is susceptible to having the
same pid repeated, especially when it competes with another instance of
the same program. This is really bad for bash implementation.
Furthermore, many shell scripts assume that pid numbers will not be used
for some length of time.
Race Description:
A B
// pid == offset == n // pid == offset == n + 1
test_and_set_bit(offset, map->page)
test_and_set_bit(offset, map->page);
pid_ns->last_pid = pid;
pid_ns->last_pid = pid;
// pid == n + 1 is freed (wait())
// Next fork()...
last = pid_ns->last_pid; // == n
pid = last + 1;
Code to reproduce it (Running multiple instances is more effective):
#include <errno.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
// The distance mod 32768 between two pids, where the first pid is expected
// to be smaller than the second.
int PidDistance(pid_t first, pid_t second) {
return (second + 32768 - first) % 32768;
}
int main(int argc, char* argv[]) {
int failed = 0;
pid_t last_pid = 0;
int i;
printf("%d\n", sizeof(pid_t));
for (i = 0; i < 10000000; ++i) {
if (i % 32786 == 0)
printf("Iter: %d\n", i/32768);
int child_exit_code = i % 256;
pid_t pid = fork();
if (pid == -1) {
fprintf(stderr, "fork failed, iteration %d, errno=%d", i, errno);
exit(1);
}
if (pid == 0) {
// Child
exit(child_exit_code);
} else {
// Parent
if (i > 0) {
int distance = PidDistance(last_pid, pid);
if (distance == 0 || distance > 30000) {
fprintf(stderr,
"Unexpected pid sequence: previous fork: pid=%d, "
"current fork: pid=%d for iteration=%d.\n",
last_pid, pid, i);
failed = 1;
}
}
last_pid = pid;
int status;
int reaped = wait(&status);
if (reaped != pid) {
fprintf(stderr,
"Wait return value: expected pid=%d, "
"got %d, iteration %d\n",
pid, reaped, i);
failed = 1;
} else if (WEXITSTATUS(status) != child_exit_code) {
fprintf(stderr,
"Unexpected exit status %x, iteration %d\n",
WEXITSTATUS(status), i);
failed = 1;
}
}
}
exit(failed);
}
Thanks to Ted Tso for the key ideas of this implementation.
Signed-off-by: Salman Qazi <sqazi@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
