linux-toradex.git/include/linux/rmap.h, branch tegra-10.9.9

Merge branch 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6

2009-09-24T14:53:22+00:00

* 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (21 commits)
  HWPOISON: Enable error_remove_page on btrfs
  HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs
  HWPOISON: Add madvise() based injector for hardware poisoned pages v4
  HWPOISON: Enable error_remove_page for NFS
  HWPOISON: Enable .remove_error_page for migration aware file systems
  HWPOISON: The high level memory error handler in the VM v7
  HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process
  HWPOISON: shmem: call set_page_dirty() with locked page
  HWPOISON: Define a new error_remove_page address space op for async truncation
  HWPOISON: Add invalidate_inode_page
  HWPOISON: Refactor truncate to allow direct truncating of page v2
  HWPOISON: check and isolate corrupted free pages v2
  HWPOISON: Handle hardware poisoned pages in try_to_unmap
  HWPOISON: Use bitmask/action code for try_to_unmap behaviour
  HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2
  HWPOISON: Add poison check to page fault handling
  HWPOISON: Add basic support for poisoned pages in fault handler v3
  HWPOISON: Add new SIGBUS error codes for hardware poison signals
  HWPOISON: Add support for poison swap entries v2
  HWPOISON: Export some rmap vma locking to outside world
  ...

ksm: no debug in page_dup_rmap()

2009-09-22T14:17:31+00:00

page_dup_rmap(), used on each mapped page when forking, was originally
just an inline atomic_inc of mapcount.  2.6.22 added CONFIG_DEBUG_VM
out-of-line checks to it, which would need to be ever-so-slightly
complicated to allow for the PageKsm() we're about to define.

But I think these checks never caught anything.  And if it's coding errors
we're worried about, such checks should be in page_remove_rmap() too, not
just when forking; whereas if it's pagetable corruption we're worried
about, then they shouldn't be limited to CONFIG_DEBUG_VM.

Oh, just revert page_dup_rmap() to an inline atomic_inc of mapcount.

Signed-off-by: Hugh Dickins 
Signed-off-by: Chris Wright 
Signed-off-by: Izik Eidus 
Cc: Nick Piggin 
Cc: Andrea Arcangeli 
Cc: Rik van Riel 
Cc: Wu Fengguang 
Cc: Balbir Singh 
Cc: Hugh Dickins 
Cc: KAMEZAWA Hiroyuki 
Cc: Lee Schermerhorn 
Cc: Avi Kivity 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

HWPOISON: The high level memory error handler in the VM v7

2009-09-16T09:50:15+00:00

Add the high level memory handler that poisons pages
that got corrupted by hardware (typically by a two bit flip in a DIMM
or a cache) on the Linux level. The goal is to prevent everyone
from accessing these pages in the future.

This done at the VM level by marking a page hwpoisoned
and doing the appropriate action based on the type of page
it is.

The code that does this is portable and lives in mm/memory-failure.c

To quote the overview comment:

High level machine check handler. Handles pages reported by the
hardware as being corrupted usually due to a 2bit ECC memory or cache
failure.

This focuses on pages detected as corrupted in the background.
When the current CPU tries to consume corruption the currently
running process can just be killed directly instead. This implies
that if the error cannot be handled for some reason it's safe to
just ignore it because no corruption has been consumed yet. Instead
when that happens another machine check will happen.

Handles page cache pages in various states. The tricky part
here is that we can access any page asynchronous to other VM
users, because memory failures could happen anytime and anywhere,
possibly violating some of their assumptions. This is why this code
has to be extremely careful. Generally it tries to use normal locking
rules, as in get the standard locks, even if that means the
error handling takes potentially a long time.

Some of the operations here are somewhat inefficient and have non
linear algorithmic complexity, because the data structures have not
been optimized for this case. This is in particular the case
for the mapping from a vma to a process. Since this case is expected
to be rare we hope we can get away with this.

There are in principle two strategies to kill processes on poison:
- just unmap the data and wait for an actual reference before
killing
- kill as soon as corruption is detected.
Both have advantages and disadvantages and should be used
in different situations. Right now both are implemented and can
be switched with a new sysctl vm.memory_failure_early_kill
The default is early kill.

The patch does some rmap data structure walking on its own to collect
processes to kill. This is unusual because normally all rmap data structure
knowledge is in rmap.c only. I put it here for now to keep
everything together and rmap knowledge has been seeping out anyways

Includes contributions from Johannes Weiner, Chris Mason, Fengguang Wu,
Nick Piggin (who did a lot of great work) and others.

Cc: npiggin@suse.de
Cc: riel@redhat.com
Signed-off-by: Andi Kleen 
Acked-by: Rik van Riel 
Reviewed-by: Hidehiro Kawai

HWPOISON: Handle hardware poisoned pages in try_to_unmap

2009-09-16T09:50:11+00:00

When a page has the poison bit set replace the PTE with a poison entry.
This causes the right error handling to be done later when a process runs
into it.

v2: add a new flag to not do that (needed for the memory-failure handler
later) (Fengguang)
v3: remove unnecessary is_migration_entry() test (Fengguang, Minchan)

Reviewed-by: Minchan Kim 
Reviewed-by: Wu Fengguang 
Signed-off-by: Andi Kleen

HWPOISON: Use bitmask/action code for try_to_unmap behaviour

2009-09-16T09:50:10+00:00

try_to_unmap currently has multiple modi (migration, munlock, normal unmap)
which are selected by magic flag variables. The logic is not very straight
forward, because each of these flag change multiple behaviours (e.g.
migration turns off aging, not only sets up migration ptes etc.)
Also the different flags interact in magic ways.

A later patch in this series adds another mode to try_to_unmap, so
this becomes quickly unmanageable.

Replace the different flags with a action code (migration, munlock, munmap)
and some additional flags as modifiers (ignore mlock, ignore aging).
This makes the logic more straight forward and allows easier extension
to new behaviours. Change all the caller to declare what they want to
do.

This patch is supposed to be a nop in behaviour. If anyone can prove
it is not that would be a bug.

Cc: Lee.Schermerhorn@hp.com
Cc: npiggin@suse.de

Signed-off-by: Andi Kleen

HWPOISON: Export some rmap vma locking to outside world

2009-09-16T09:50:04+00:00

Needed for later patch that walks rmap entries on its own.

This used to be very frowned upon, but memory-failure.c does
some rather specialized rmap walking and rmap has been stable
for quite some time, so I think it's ok now to export it.

Signed-off-by: Andi Kleen

rmap: fixup page_referenced() for nommu systems

2009-06-23T19:50:05+00:00

After the recent changes that went into mm/vmscan.c to overhaul stuff, we
ended up with these warnings on no-mmu systems:

  mm/vmscan.c: In function `shrink_page_list':
  mm/vmscan.c:580: warning: unused variable `vm_flags'
  mm/vmscan.c: In function `shrink_active_list':
  mm/vmscan.c:1294: warning: `vm_flags' may be used uninitialized in this function
  mm/vmscan.c:1242: note: `vm_flags' was declared here

This is because the no-mmu function defines page_referenced() to work on
the first argument only (the page).  It does not clear the vm_flags given
to it because for no-mmu systems, they never actually get utilized.  Since
that is no longer strictly true, we need to set vm_flags to 0 like
everyone else so gcc can do proper dead code elimination without annoying
us with unused warnings.

Signed-off-by: Mike Frysinger 
Cc: David Howells 
Acked-by: David McCullough 
Cc: Greg Ungerer 
Cc: Paul Mundt 
Cc: Wu Fengguang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmscan: report vm_flags in page_referenced()

2009-06-17T02:47:44+00:00

Collect vma->vm_flags of the VMAs that actually referenced the page.

This is preparing for more informed reclaim heuristics, eg.  to protect
executable file pages more aggressively.  For now only the VM_EXEC bit
will be used by the caller.

Thanks to Johannes, Peter and Minchan for all the good tips.

Acked-by: Peter Zijlstra 
Reviewed-by: Rik van Riel 
Reviewed-by: Minchan Kim 
Reviewed-by: Johannes Weiner 
Signed-off-by: Wu Fengguang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove CONFIG_UNEVICTABLE_LRU config option

2009-06-17T02:47:42+00:00

Currently, nobody wants to turn UNEVICTABLE_LRU off.  Thus this
configurability is unnecessary.

Signed-off-by: KOSAKI Motohiro 
Cc: Johannes Weiner 
Cc: Andi Kleen 
Acked-by: Minchan Kim 
Cc: David Woodhouse 
Cc: Matt Mackall 
Cc: Rik van Riel 
Cc: Lee Schermerhorn 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

badpage: remove vma from page_remove_rmap

2009-01-06T23:59:07+00:00

Remove page_remove_rmap()'s vma arg, which was only for the Eeek message.
And remove the BUG_ON(page_mapcount(page) == 0) from CONFIG_DEBUG_VM's
page_dup_rmap(): we're trying to be more resilient about that than BUGs.

Signed-off-by: Hugh Dickins 
Cc: Nick Piggin 
Cc: Christoph Lameter 
Cc: Mel Gorman 
Cc: Rik van Riel 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds