linux/Documentation/vm
Naoya Horiguchi 3ba08129e3 mm/memory-failure.c: support use of a dedicated thread to handle SIGBUS(BUS_MCEERR_AO)
Currently memory error handler handles action optional errors in the
deferred manner by default.  And if a recovery aware application wants
to handle it immediately, it can do it by setting PF_MCE_EARLY flag.
However, such signal can be sent only to the main thread, so it's
problematic if the application wants to have a dedicated thread to
handler such signals.

So this patch adds dedicated thread support to memory error handler.  We
have PF_MCE_EARLY flags for each thread separately, so with this patch
AO signal is sent to the thread with PF_MCE_EARLY flag set, not the main
thread.  If you want to implement a dedicated thread, you call prctl()
to set PF_MCE_EARLY on the thread.

Memory error handler collects processes to be killed, so this patch lets
it check PF_MCE_EARLY flag on each thread in the collecting routines.

No behavioral change for all non-early kill cases.

Tony said:

: The old behavior was crazy - someone with a multithreaded process might
: well expect that if they call prctl(PF_MCE_EARLY) in just one thread, then
: that thread would see the SIGBUS with si_code = BUS_MCEERR_A0 - even if
: that thread wasn't the main thread for the process.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Cc: Kamil Iskra <iskra@mcs.anl.gov>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Chen Gong <gong.chen@linux.jf.intel.com>
Cc: <stable@vger.kernel.org>	[3.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-06-04 16:54:13 -07:00
..
.gitignore
00-INDEX Documentation/: update 00-INDEX files 2014-02-10 16:01:40 -08:00
active_mm.txt
balance
cleancache.txt Cleanups: rename of flush to invalidate, moving reporting of statistics 2012-03-22 19:52:47 -07:00
frontswap.txt doc: fix quite a few typos within Documentation 2012-11-19 14:28:24 +01:00
highmem.txt
hugetlbpage.txt hugepage: mention libhugetlbfs in doc 2013-09-11 15:57:39 -07:00
hwpoison.txt mm/memory-failure.c: support use of a dedicated thread to handle SIGBUS(BUS_MCEERR_AO) 2014-06-04 16:54:13 -07:00
ksm.txt ksm: add some comments 2013-02-23 17:50:23 -08:00
numa doc: fix broken references 2011-09-27 18:08:04 +02:00
numa_memory_policy.txt Documentation/vm/numa_memory_policy.txt: fix wrong document in numa_memory_policy.txt 2014-04-18 16:40:08 -07:00
overcommit-accounting mm: add overcommit_kbytes sysctl variable 2014-01-21 16:19:44 -08:00
page_migration
pagemap.txt Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2013-07-04 11:40:58 -07:00
slub.txt Documentations: Fix slabinfo.c directory in vm/slub.txt 2012-05-10 11:45:23 +03:00
soft-dirty.txt mm: track vma changes with VM_SOFTDIRTY bit 2013-09-11 15:57:56 -07:00
split_page_table_lock x86, mm: do not leak page->ptl for pmd page tables 2013-11-21 16:42:28 -08:00
transhuge.txt doc: spelling error changes 2014-05-05 15:32:05 +02:00
unevictable-lru.txt doc: fix double words 2014-03-21 13:16:58 +01:00
zswap.txt Documentation/vm/zswap.txt: fix typos 2013-11-13 12:09:05 +09:00