Tracking of dirty pages in shared writeable mmap()s.
The idea is simple: write protect clean shared writeable pages, catch the
write-fault, make writeable and set dirty. On page write-back clean all the
PTE dirty bits and write protect them once again.
The implementation is a tad harder, mainly because the default
backing_dev_info capabilities were too loosely maintained. Hence it is not
enough to test the backing_dev_info for cap_account_dirty.
The current heuristic is as follows, a VMA is eligible when:
- its shared writeable
(vm_flags & (VM_WRITE|VM_SHARED)) == (VM_WRITE|VM_SHARED)
- it is not a 'special' mapping
(vm_flags & (VM_PFNMAP|VM_INSERTPAGE)) == 0
- the backing_dev_info is cap_account_dirty
mapping_cap_account_dirty(vma->vm_file->f_mapping)
- f_op->mmap() didn't change the default page protection
Page from remap_pfn_range() are explicitly excluded because their COW
semantics are already horrid enough (see vm_normal_page() in do_wp_page()) and
because they don't have a backing store anyway.
mprotect() is taught about the new behaviour as well. However it overrides
the last condition.
Cleaning the pages on write-back is done with page_mkclean() a new rmap call.
It can be called on any page, but is currently only implemented for mapped
pages, if the page is found the be of a VMA that accounts dirty pages it will
also wrprotect the PTE.
Finally, in fs/buffers.c:try_to_free_buffers(); remove clear_page_dirty() from
under ->private_lock. This seems to be safe, since ->private_lock is used to
serialize access to the buffers, not the page itself. This is needed because
clear_page_dirty() will call into page_mkclean() and would thereby violate
locking order.
[dhowells@redhat.com: Provide a page_mkclean() implementation for NOMMU]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce a VM_BUG_ON, which is turned on with CONFIG_DEBUG_VM. Use this
in the lightweight, inline refcounting functions; PageLRU and PageActive
checks in vmscan, because they're pretty well confined to vmscan. And in
page allocate/free fastpaths which can be the hottest parts of the kernel
for kbuilds.
Unlike BUG_ON, VM_BUG_ON must not be used to execute statements with
side-effects, and should not be used outside core mm code.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Give non-highmem architectures access to the kmap API for the purposes of
overriding (this is what the attached patch does).
The proposal is that we should now require all architectures with coherence
issues to manage data coherence via the kmap/kunmap API. Thus driver
writers never have to write code like
kmap(page)
modify data in page
flush_kernel_dcache_page(page)
kunmap(page)
instead, kmap/kunmap will manage the coherence and driver (and filesystem)
writers don't need to worry about how to flush between kmap and kunmap.
For most architectures, the page only needs to be flushed if it was
actually written to *and* there are user mappings of it, so the best
implementation looks to be: clear the page dirty pte bit in the kernel page
tables on kmap and on kunmap, check page->mappings for user maps, and then
the dirty bit, and only flush if it both has user mappings and is dirty.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Original commit code assumes, that when a buffer on BJ_SyncData list is
locked, it is being written to disk. But this is not true and hence it can
lead to a potential data loss on crash. Also the code didn't count with
the fact that journal_dirty_data() can steal buffers from committing
transaction and hence could write buffers that no longer belong to the
committing transaction. Finally it could possibly happen that we tried
writing out one buffer several times.
The patch below tries to solve these problems by a complete rewrite of the
data commit code. We go through buffers on t_sync_datalist, lock buffers
needing write out and store them in an array. Buffers are also immediately
refiled to BJ_Locked list or unfiled (if the write out is completed). When
the array is full or we have to block on buffer lock, we submit all
accumulated buffers for IO.
[suitable for 2.6.18.x around the 2.6.19-rc2 timeframe]
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
get_cpu_var()/per_cpu()/__get_cpu_var() arguments must be simple
identifiers. Otherwise the arch dependent implementations might break.
This patch enforces the correct usage of the macros by producing a syntax
error if the variable is not a simple identifier.
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The scheduler will stop load balancing if the most busy processor contains
processes pinned via processor affinity.
The scheduler currently only does one search for busiest cpu. If it cannot
pull any tasks away from the busiest cpu because they were pinned then the
scheduler goes into a corner and sulks leaving the idle processors idle.
F.e. If you have processor 0 busy running four tasks pinned via taskset,
there are none on processor 1 and one just started two processes on
processor 2 then the scheduler will not move one of the two processes away
from processor 2.
This patch fixes that issue by forcing the scheduler to come out of its
corner and retrying the load balancing by considering other processors for
load balancing.
This patch was originally developed by John Hawkes and discussed at
http://marc.theaimsgroup.com/?l=linux-kernel&m=113901368523205&w=2.
I have removed extraneous material and gone back to equipping struct rq
with the cpu the queue is associated with since this makes the patch much
easier and it is likely that others in the future will have the same
difficulty of figuring out which processor owns which runqueue.
The overhead added through these patches is a single word on the stack if
the kernel is configured to support 32 cpus or less (32 bit). For 32 bit
environments the maximum number of cpus that can be configued is 255 which
would result in the use of 32 bytes additional on the stack. On IA64 up to
1k cpus can be configured which will result in the use of 128 additional
bytes on the stack. The maximum additional cache footprint is one
cacheline. Typically memory use will be much less than a cacheline and the
additional cpumask will be placed on the stack in a cacheline that already
contains other local variable.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: John Hawkes <hawkes@sgi.com>
Cc: "Siddha, Suresh B" <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Peter Williams <pwil3058@bigpond.net.au>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add supplemental SSE3 instructions flag, and Direct Cache Access flag.
As described in "Intel Processor idenfication and the CPUID instruction
AP485 Sept 2006"
AK: also added for x86-64
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
The counter is exported to /sys that keeps track of the
number of thermal events, such that the user knows how bad the
thermal problem might be (since the logging to syslog and mcelog
is rate limited).
AK: Fixed cpu hotplug locking
Signed-off-by: Dmitriy Zavin <dmitriyz@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Refactor the event processing (syslog messaging and rate limiting)
into separate file therm_throt.c. This allows consistent reporting
of CPU thermal throttle events.
After ACK'ing the interrupt, if the event is current, the user
(p4.c/mce_intel.c) calls therm_throt_process to log (and rate limit)
the event. If that function returns 1, the user has the option to log
things further (such as to mce_log in x86_64).
AK: minor cleanup
Signed-off-by: Dmitriy Zavin <dmitriyz@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
The current time_before/time_after macros will fail typechecks
when passed u64 values (as returned by get_jiffies_64()). On 64bit
systems, this will just result in a warning about mismatching types
without explicit casts, but since unsigned long and u64
(unsigned long long) are of same size, it will still work.
On 32bit systems, a long is 32bits, so the value from get_jiffies_64()
will be truncated by the cast and thus lose all the precision gained by
64bit jiffies.
Signed-off-by: Dmitriy Zavin <dmitriyz@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Fix
linux/arch/x86_64/kernel/traps.c: In function 'dump_trace':
linux/arch/x86_64/kernel/traps.c:275: warning: cast to pointer from integer of different size
with allnoconfig
Cc: jbeulich@novell.com
Signed-off-by: Andi Kleen <ak@suse.de>
Some buggy systems can machine check when config space accesses
happen for some non existent devices. i386/x86-64 do some early
device scans that might trigger this. Allow pci=noearly to disable
this. Also when type 1 is disabling also don't do any early
accesses which are always type1.
This moves the pci= configuration parsing to be a early parameter.
I don't think this can break anything because it only changes
a single global that is only used by PCI.
Cc: gregkh@suse.de
Cc: Trammell Hudson <hudson@osresearch.net>
Signed-off-by: Andi Kleen <ak@suse.de>
This is useful on systems with broken PCI bus. Affects various
scans in x86-64 and i386's early ACPI quirk scan.
Cc: gregkh@suse.de
Cc: len.brown@intel.com
Cc: Trammell Hudson <hudson@osresearch.net>
Signed-off-by: Andi Kleen <ak@suse.de>
SYSENTER can cause a NT to be set which might cause crashes on the IRET
in the next task.
Following similar i386 patch from Linus.
Signed-off-by: Andi Kleen <ak@suse.de>
Current gcc generates calls not jumps to noreturn functions. When that happens the
return address can point to the next function, which confuses the unwinder.
This patch works around it by marking asynchronous exception
frames in contrast normal call frames in the unwind information. Then teach
the unwinder to decode this.
For normal call frames the unwinder now subtracts one from the address which avoids
this problem. The standard libgcc unwinder uses the same trick.
It doesn't include adjustment of the printed address (i.e. for the original
example, it'd still be kernel_math_error+0 that gets displayed, but the
unwinder wouldn't get confused anymore.
This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16
unfortunately because earlier binutils don't support .cfi_signal_frame
[AK: added automatic detection of the new binutils and wrote description]
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
We do some additional CPU synchronization in gettimeofday et.al. to make
sure the time stamps are always monotonic over multiple CPUs. But on
single core systems that is not needed. So don't do it.
Signed-off-by: Andi Kleen <ak@suse.de>
Got it. i8259A_resume calls init_8259A(0) unconditionally, even if
auto_eoi has been set. Keep track of the current status and restore that
on resume. This fixes it for AMD64 and i386.
Signed-off-by: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Sometimes, bug reports come in where we've had an oops, and the
only record we have is what the reporter saw on screen shortly
before the system locked up completely. Unfortunatly, syslog
only prints lines beginning with KERN_EMERG to the console, so
some lines get lost.
An example of this can be seen at https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=203723
Some of this information isn't vital to diagnosis, but some parts
are useful, such as the tainted flag.
Signed-off-by: Dave Jones <davej@redhat.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Fix pack_descriptor:
1. flags are bits 20-23 in the high word
2. limit's 4 msb are bits 16-19 in the high word
These haven't mattered so far, because all users have had small limits
and a flags setting of 0.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
===================================================================
On Sat, Sep 09, 2006 at 04:14:29PM +0200, Andi Kleen wrote:
> [patch] Looks reasonable, but probably not for 2.6.18 because this stuff
> is already too fragile and it is probably too risky to do any big changes now
> since not enough testing time is left. Can you please resubmit
> it with proper description and signed-off-by line? I can queue it for .19 then
>
> -Andi
Patch inserts PCI memory mapped config region(s) into the resource map. This
will allow for the MMCCONFIG regions to be marked as busy in the iomem
address space as well as the regions(s) showing up in /proc/iomem.
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Patch inserts the GART region into the iomem resource map. The GART will then
be visible within /proc/iomem. It will also allow for other users
utilizing the GART to subreserve the region (agp or IOMMU).
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Needs earlier patch to split type 1 probing from use.
This patch should fix the x86 macs where type 1 PCI config space access
doesn't work, but MCFG does. They also don't have a usable e820 table
so the e820 sanity check failed.
Instead assume now that if type 1 doesn't work then MCFG must work
and don't do the e820 check.
Signed-off-by: Andi Kleen <ak@suse.de>
First probe if type1/2 accesses work, but then only initialize them at the end.
This is useful for a later patch that needs this information inbetween.
Signed-off-by: Andi Kleen <ak@suse.de>
Previously exit_idle would be called more often than enter_idle
Now instead of using complicated tests just keep track of it
using the per CPU variable as a flip flop. I moved the idle state into the
PDA to make the access more efficient.
Original bug report and an initial patch from Stephane Eranian,
but redone by AK.
Cc: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andi Kleen <ak@suse.de>
kexec has been marked experimental for a year now and all
of the serious problems have been worked through. So it
is time (if not past time) to remove the experimental mark.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andi Kleen <ak@suse.de>
kexec has been marked experimental for a year now and all
of the serious problems have been worked through. So it
is time (if not past time) to remove the experimental mark.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Before 2.6.16 this was changed to work around code that accessed
CPUs not in the possible map. But that code should be all fixed now,
so mark it __initdata again.
Signed-off-by: Andi Kleen <ak@suse.de>
Reindent the macros in x86-64 pda.h, making them much more readable.
Follows Jeremy's i386 version of this.
No functional changes
Signed-off-by: Andi Kleen <ak@suse.de>
Fix
linux/fs/compat.c: In function compat_sys_pselect7
linux/fs/compat.c:1869: warning: ignoring return value of copy_to_user, declared with attribute warn_unused_result
To make it easier to handle I changed to semantics to not try to
write out a timespec if an error occurred. I hope that's ok.
Cc: dwmw2@infradead.org
Signed-off-by: Andi Kleen <ak@suse.de>
- Don't zero for __copy_from_user_inatomic following i386.
This will prevent spurious zeros for parallel file system writers when
one does a exception
- The string instruction version didn't zero the output on
exception. Oops.
Also I cleaned up the code a bit while I was at it and added a minor
optimization to the string instruction path.
Signed-off-by: Andi Kleen <ak@suse.de>
Add HPET(s) into resource map. This will allow for the HPET(s) to be
visibile within /proc/iomem.
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This patch places the IOAPIC(s) and the Local APIC specified by ACPI
tables into the resource map. The APICs will then be visible within
/proc/iomem
Signed-off-by: Aaron Durbin <adurbin@google.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Add early i386 fault handlers with debug information for common faults.
Handles:
divide error
invalid opcode
protection fault
page fault
Also adds code to detect early recursive/multiple faults and halt the
system when they happen (taken from x86_64.)
Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
We allow for the fact that the guest kernel may not run in ring 0. This
requires some abstraction in a few places when setting %cs or checking
privilege level (user vs kernel).
This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather
than using #define USER_MODE_MASK which depends on a config option, we use
Zach's more flexible approach of assuming ring 3 == userspace. I also used
"get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in
the code...
1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a
get_kernel_rpl() macro, and don't assume it's zero.
And:
Clean up of patch for letting kernel run other than ring 0:
a. Add some comments about the SEGMENT_IS_*_CODE() macros.
b. Add a USER_RPL macro. (Code was comparing a value to a mask
in some places and to the magic number 3 in other places.)
c. Add macros for table indicator field and use them.
d. Change the entry.S tests for LDT stack segment to use the macros
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Abstract sensitive instructions in assembler code, replacing them with macros
(which currently are #defined to the native versions). We use long names:
assembler is case-insensitive, so if something goes wrong and macros do not
expand, it would assemble anyway.
Resulting object files are exactly the same as before.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Fix
linux/arch/x86_64/kernel/process.c: In function __switch_to:
linux/arch/x86_64/kernel/process.c:626: warning: assignment makes integer from pointer without a cast
Signed-off-by: Andi Kleen <ak@suse.de>
