Commit Graph

359 Commits

Author SHA1 Message Date
Peter Zijlstra 5c723ba5b7 mm: Fix fixup_user_fault() for MMU=n
In commit 2efaca927f ("mm/futex: fix futex writes on archs with SW
tracking of dirty & young") we forgot about MMU=n.  This patch fixes
that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: David Howells <dhowells@redhat.com>
Link: http://lkml.kernel.org/r/1311761831.24752.413.camel@twins
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-08-08 12:11:02 -07:00
Len Brown d0e323b470 Merge branch 'apei' into apei-release
Some trivial conflicts due to other various merges
adding to the end of common lists sooner than this one.

	arch/ia64/Kconfig
	arch/powerpc/Kconfig
	arch/x86/Kconfig
	lib/Kconfig
	lib/Makefile

Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03 11:30:42 -04:00
Huang Ying ea8f5fb8a7 HWPoison: add memory_failure_queue()
memory_failure() is the entry point for HWPoison memory error
recovery.  It must be called in process context.  But commonly
hardware memory errors are notified via MCE or NMI, so some delayed
execution mechanism must be used.  In MCE handler, a work queue + ring
buffer mechanism is used.

In addition to MCE, now APEI (ACPI Platform Error Interface) GHES
(Generic Hardware Error Source) can be used to report memory errors
too.  To add support to APEI GHES memory recovery, a mechanism similar
to that of MCE is implemented.  memory_failure_queue() is the new
entry point that can be called in IRQ context.  The next step is to
make MCE handler uses this interface too.

Signed-off-by: Huang Ying <ying.huang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>
2011-08-03 11:15:58 -04:00
Benjamin Herrenschmidt 2efaca927f mm/futex: fix futex writes on archs with SW tracking of dirty & young
I haven't reproduced it myself but the fail scenario is that on such
machines (notably ARM and some embedded powerpc), if you manage to hit
that futex path on a writable page whose dirty bit has gone from the PTE,
you'll livelock inside the kernel from what I can tell.

It will go in a loop of trying the atomic access, failing, trying gup to
"fix it up", getting succcess from gup, go back to the atomic access,
failing again because dirty wasn't fixed etc...

So I think you essentially hang in the kernel.

The scenario is probably rare'ish because affected architecture are
embedded and tend to not swap much (if at all) so we probably rarely hit
the case where dirty is missing or young is missing, but I think Shan has
a piece of SW that can reliably reproduce it using a shared writable
mapping & fork or something like that.

On archs who use SW tracking of dirty & young, a page without dirty is
effectively mapped read-only and a page without young unaccessible in the
PTE.

Additionally, some architectures might lazily flush the TLB when relaxing
write protection (by doing only a local flush), and expect a fault to
invalidate the stale entry if it's still present on another processor.

The futex code assumes that if the "in_atomic()" access -EFAULT's, it can
"fix it up" by causing get_user_pages() which would then be equivalent to
taking the fault.

However that isn't the case.  get_user_pages() will not call
handle_mm_fault() in the case where the PTE seems to have the right
permissions, regardless of the dirty and young state.  It will eventually
update those bits ...  in the struct page, but not in the PTE.

Additionally, it will not handle the lazy TLB flushing that can be
required by some architectures in the fault case.

Basically, gup is the wrong interface for the job.  The patch provides a
more appropriate one which boils down to just calling handle_mm_fault()
since what we are trying to do is simulate a real page fault.

The futex code currently attempts to write to user memory within a
pagefault disabled section, and if that fails, tries to fix it up using
get_user_pages().

This doesn't work on archs where the dirty and young bits are maintained
by software, since they will gate access permission in the TLB, and will
not be updated by gup().

In addition, there's an expectation on some archs that a spurious write
fault triggers a local TLB flush, and that is missing from the picture as
well.

I decided that adding those "features" to gup() would be too much for this
already too complex function, and instead added a new simpler
fixup_user_fault() which is essentially a wrapper around handle_mm_fault()
which the futex code can call.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix some nits Darren saw, fiddle comment layout]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Shan Hai <haishan.bai@gmail.com>
Tested-by: Shan Hai <haishan.bai@gmail.com>
Cc: David Laight <David.Laight@ACULAB.COM>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Darren Hart <darren.hart@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:11 -07:00
Hugh Dickins 85821aab39 mm: truncate functions are in truncate.c
Correct comment on truncate_inode_pages*() in linux/mm.h; and remove
declaration of page_unuse(), it didn't exist even in 2.2.26 or 2.4.0!

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:10 -07:00
KOSAKI Motohiro c27fe4c894 pagewalk: add locking-rule comments
Originally, walk_hugetlb_range() didn't require a caller take any lock.
But commit d33b9f45bd ("mm: hugetlb: fix hugepage memory leak in
walk_page_range") changed its rule.  Because it added find_vma() call in
walk_hugetlb_range().

Any locking-rule change commit should write a doc too.

[akpm@linux-foundation.org: clarify comment]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:08 -07:00
Ian Campbell 33dd4e0ec9 mm: make some struct page's const
These uses are read-only and in a subsequent patch I have a const struct
page in my hand...

[akpm@linux-foundation.org: fix warnings in lowmem_page_address()]
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-07-25 20:57:07 -07:00
Linus Torvalds bbd9d6f7fb Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (107 commits)
  vfs: use ERR_CAST for err-ptr tossing in lookup_instantiate_filp
  isofs: Remove global fs lock
  jffs2: fix IN_DELETE_SELF on overwriting rename() killing a directory
  fix IN_DELETE_SELF on overwriting rename() on ramfs et.al.
  mm/truncate.c: fix build for CONFIG_BLOCK not enabled
  fs:update the NOTE of the file_operations structure
  Remove dead code in dget_parent()
  AFS: Fix silly characters in a comment
  switch d_add_ci() to d_splice_alias() in "found negative" case as well
  simplify gfs2_lookup()
  jfs_lookup(): don't bother with . or ..
  get rid of useless dget_parent() in btrfs rename() and link()
  get rid of useless dget_parent() in fs/btrfs/ioctl.c
  fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers
  drivers: fix up various ->llseek() implementations
  fs: handle SEEK_HOLE/SEEK_DATA properly in all fs's that define their own llseek
  Ext4: handle SEEK_HOLE/SEEK_DATA generically
  Btrfs: implement our own ->llseek
  fs: add SEEK_HOLE and SEEK_DATA flags
  reiserfs: make reiserfs default to barrier=flush
  ...

Fix up trivial conflicts in fs/xfs/linux-2.6/xfs_super.c due to the new
shrinker callout for the inode cache, that clashed with the xfs code to
start the periodic workers later.
2011-07-22 19:02:39 -07:00
Dave Chinner b0d40c92ad superblock: introduce per-sb cache shrinker infrastructure
With context based shrinkers, we can implement a per-superblock
shrinker that shrinks the caches attached to the superblock. We
currently have global shrinkers for the inode and dentry caches that
split up into per-superblock operations via a coarse proportioning
method that does not batch very well.  The global shrinkers also
have a dependency - dentries pin inodes - so we have to be very
careful about how we register the global shrinkers so that the
implicit call order is always correct.

With a per-sb shrinker callout, we can encode this dependency
directly into the per-sb shrinker, hence avoiding the need for
strictly ordering shrinker registrations. We also have no need for
any proportioning code for the shrinker subsystem already provides
this functionality across all shrinkers. Allowing the shrinker to
operate on a single superblock at a time means that we do less
superblock list traversals and locking and reclaim should batch more
effectively. This should result in less CPU overhead for reclaim and
potentially faster reclaim of items from each filesystem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 20:47:10 -04:00
Dave Chinner e9299f5058 vmscan: add customisable shrinker batch size
For shrinkers that have their own cond_resched* calls, having
shrink_slab break the work down into small batches is not
paticularly efficient. Add a custom batchsize field to the struct
shrinker so that shrinkers can use a larger batch size if they
desire.

A value of zero (uninitialised) means "use the default", so
behaviour is unchanged by this patch.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-07-20 01:44:32 -04:00
Tejun Heo 1e01979c8f x86, numa: Implement pfn -> nid mapping granularity check
SPARSEMEM w/o VMEMMAP and DISCONTIGMEM, both used only on 32bit, use
sections array to map pfn to nid which is limited in granularity.  If
NUMA nodes are laid out such that the mapping cannot be accurate, boot
will fail triggering BUG_ON() in mminit_verify_page_links().

On 32bit, it's 512MiB w/ PAE and SPARSEMEM.  This seems to have been
granular enough until commit 2706a0bf7b (x86, NUMA: Enable
CONFIG_AMD_NUMA on 32bit too).  Apparently, there is a machine which
aligns NUMA nodes to 128MiB and has only AMD NUMA but not SRAT.  This
led to the following BUG_ON().

 On node 0 totalpages: 2096615
   DMA zone: 32 pages used for memmap
   DMA zone: 0 pages reserved
   DMA zone: 3927 pages, LIFO batch:0
   Normal zone: 1740 pages used for memmap
   Normal zone: 220978 pages, LIFO batch:31
   HighMem zone: 16405 pages used for memmap
   HighMem zone: 1853533 pages, LIFO batch:31
 BUG: Int 6: CR2   (null)
      EDI   (null)  ESI 00000002  EBP 00000002  ESP c1543ecc
      EBX f2400000  EDX 00000006  ECX   (null)  EAX 00000001
      err   (null)  EIP c16209aa   CS 00000060  flg 00010002
 Stack: f2400000 00220000 f7200800 c1620613 00220000 01000000 04400000 00238000
          (null) f7200000 00000002 f7200b58 f7200800 c1620929 000375fe   (null)
        f7200b80 c16395f0 00200a02 f7200a80   (null) 000375fe 00000002   (null)
 Pid: 0, comm: swapper Not tainted 2.6.39-rc5-00181-g2706a0b #17
 Call Trace:
  [<c136b1e5>] ? early_fault+0x2e/0x2e
  [<c16209aa>] ? mminit_verify_page_links+0x12/0x42
  [<c1620613>] ? memmap_init_zone+0xaf/0x10c
  [<c1620929>] ? free_area_init_node+0x2b9/0x2e3
  [<c1607e99>] ? free_area_init_nodes+0x3f2/0x451
  [<c1601d80>] ? paging_init+0x112/0x118
  [<c15f578d>] ? setup_arch+0x791/0x82f
  [<c15f43d9>] ? start_kernel+0x6a/0x257

This patch implements node_map_pfn_alignment() which determines
maximum internode alignment and update numa_register_memblks() to
reject NUMA configuration if alignment exceeds the pfn -> nid mapping
granularity of the memory model as determined by PAGES_PER_SECTION.

This makes the problematic machine boot w/ flatmem by rejecting the
NUMA config and provides protection against crazy NUMA configurations.

Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110712074534.GB2872@htj.dyndns.org
LKML-Reference: <20110628174613.GP478@escobedo.osrc.amd.com>
Reported-and-Tested-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
Cc: Conny Seidel <conny.seidel@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2011-07-12 21:58:29 -07:00
Jiri Slaby 3864601387 mm: extract exe_file handling from procfs
Setup and cleanup of mm_struct->exe_file is currently done in fs/proc/.
This was because exe_file was needed only for /proc/<pid>/exe.  Since we
will need the exe_file functionality also for core dumps (so core name can
contain full binary path), built this functionality always into the
kernel.

To achieve that move that out of proc FS to the kernel/ where in fact it
should belong.  By doing that we can make dup_mm_exe_file static.  Also we
can drop linux/proc_fs.h inclusion in fs/exec.c and kernel/fork.c.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 17:12:36 -07:00
KOSAKI Motohiro ca16d140af mm: don't access vm_flags as 'int'
The type of vma->vm_flags is 'unsigned long'. Neither 'int' nor
'unsigned int'. This patch fixes such misuse.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
[ Changed to use a typedef - we'll extend it to cover more cases
  later, since there has been discussion about making it a 64-bit
  type..                      - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-26 09:20:31 -07:00
Hugh Dickins c856507f2b mm: remove last trace of shmem_get_unmapped_area
Remove noMMU declaration of shmem_get_unmapped_area() from mm.h: it fell
out of use in 2.6.21 and ceased to exist in 2.6.29.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:31 -07:00
Matt Fleming 172703b08c mm: delete non-atomic mm counter implementation
The problem with having two different types of counters is that developers
adding new code need to keep in mind whether it's safe to use both the
atomic and non-atomic implementations.  For example, when adding new
callers of the *_mm_counter() functions a developer needs to ensure that
those paths are always executed with page_table_lock held, in case we're
using the non-atomic implementation of mm counters.

Hugh Dickins introduced the atomic mm counters in commit f412ac08c9
("[PATCH] mm: fix rss and mmlist locking").  When asked why he left the
non-atomic counters around he said,

  | The only reason was to avoid adding costly atomic operations into a
  | configuration that had no need for them there: the page_table_lock
  | sufficed.
  |
  | Certainly it would be simpler just to delete the non-atomic variant.
  |
  | And I think it's fair to say that any configuration on which we're
  | measuring performance to that degree (rather than "does it boot fast?"
  | type measurements), would already be going the split ptlocks route.

Removing the non-atomic counters eases the maintenance burden because
developers no longer have to mindful of the two implementations when using
*_mm_counter().

Note that all architectures provide a means of atomically updating
atomic_long_t variables, even if they have to revert to the generic
spinlock implementation because they don't support 64-bit atomic
instructions (see lib/atomic64.c).

Signed-off-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:30 -07:00
Daniel Kiper ba93fa81b5 mm: do not define PFN_SECTION_SHIFT if !CONFIG_SPARSEMEM
Do not define PFN_SECTION_SHIFT if !CONFIG_SPARSEMEM.

Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:29 -07:00
Daniel Kiper bf4e8902ee mm: enable set_page_section() only if CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP
set_page_section() is meaningful only in CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP context.  Move it to proper place and amend
accordingly functions which are using it.

Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:28 -07:00
Ying Han 1495f230fa vmscan: change shrinker API by passing shrink_control struct
Change each shrinker's API by consolidating the existing parameters into
shrink_control struct.  This will simplify any further features added w/o
touching each file of shrinker.

[akpm@linux-foundation.org: fix build]
[akpm@linux-foundation.org: fix warning]
[kosaki.motohiro@jp.fujitsu.com: fix up new shrinker API]
[akpm@linux-foundation.org: fix xfs warning]
[akpm@linux-foundation.org: update gfs2]
Signed-off-by: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:26 -07:00
Ying Han a09ed5e000 vmscan: change shrink_slab() interfaces by passing shrink_control
Consolidate the existing parameters to shrink_slab() into a new
shrink_control struct.  This is needed later to pass the same struct to
shrinkers.

Signed-off-by: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:25 -07:00
Dave Hansen a238ab5b02 mm: break out page allocation warning code
This originally started as a simple patch to give vmalloc() some more
verbose output on failure on top of the plain page allocator messages.
Johannes suggested that it might be nicer to lead with the vmalloc() info
_before_ the page allocator messages.

But, I do think there's a lot of value in what __alloc_pages_slowpath()
does with its filtering and so forth.

This patch creates a new function which other allocators can call instead
of relying on the internal page allocator warnings.  It also gives this
function private rate-limiting which separates it from other
printk_ratelimit() users.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:21 -07:00
Peter Zijlstra 97a894136f mm: Remove i_mmap_lock lockbreak
Hugh says:
 "The only significant loser, I think, would be page reclaim (when
  concurrent with truncation): could spin for a long time waiting for
  the i_mmap_mutex it expects would soon be dropped? "

Counter points:
 - cpu contention makes the spin stop (need_resched())
 - zap pages should be freeing pages at a higher rate than reclaim
   ever can

I think the simplification of the truncate code is definitely worth it.

Effectively reverts: 2aa15890f3 ("mm: prevent concurrent
unmap_mapping_range() on the same inode") and takes out the code that
caused its problem.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:17 -07:00
Peter Zijlstra d16dfc550f mm: mmu_gather rework
Rework the existing mmu_gather infrastructure.

The direct purpose of these patches was to allow preemptible mmu_gather,
but even without that I think these patches provide an improvement to the
status quo.

The first 9 patches rework the mmu_gather infrastructure.  For review
purpose I've split them into generic and per-arch patches with the last of
those a generic cleanup.

The next patch provides generic RCU page-table freeing, and the followup
is a patch converting s390 to use this.  I've also got 4 patches from
DaveM lined up (not included in this series) that uses this to implement
gup_fast() for sparc64.

Then there is one patch that extends the generic mmu_gather batching.

After that follow the mm preemptibility patches, these make part of the mm
a lot more preemptible.  It converts i_mmap_lock and anon_vma->lock to
mutexes which together with the mmu_gather rework makes mmu_gather
preemptible as well.

Making i_mmap_lock a mutex also enables a clean-up of the truncate code.

This also allows for preemptible mmu_notifiers, something that XPMEM I
think wants.

Furthermore, it removes the new and universially detested unmap_mutex.

This patch:

Remove the first obstacle towards a fully preemptible mmu_gather.

The current scheme assumes mmu_gather is always done with preemption
disabled and uses per-cpu storage for the page batches.  Change this to
try and allocate a page for batching and in case of failure, use a small
on-stack array to make some progress.

Preemptible mmu_gather is desired in general and usable once i_mmap_lock
becomes a mutex.  Doing it before the mutex conversion saves us from
having to rework the code by moving the mmu_gather bits inside the
pte_lock.

Also avoid flushing the tlb batches from under the pte lock, this is
useful even without the i_mmap_lock conversion as it significantly reduces
pte lock hold times.

[akpm@linux-foundation.org: fix comment tpyo]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Miller <davem@davemloft.net>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Tony Luck <tony.luck@intel.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:12 -07:00
Michal Hocko d05f3169c0 mm: make expand_downwards() symmetrical with expand_upwards()
Currently we have expand_upwards exported while expand_downwards is
accessible only via expand_stack or expand_stack_downwards.

check_stack_guard_page is a nice example of the asymmetry.  It uses
expand_stack for VM_GROWSDOWN while expand_upwards is called for
VM_GROWSUP case.

Let's clean this up by exporting both functions and make those names
consistent.  Let's use expand_{upwards,downwards} because expanding
doesn't always involve stack manipulation (an example is
ia64_do_page_fault which uses expand_upwards for registers backing store
expansion).  expand_downwards has to be defined for both
CONFIG_STACK_GROWS{UP,DOWN} because get_arg_page calls the downwards
version in the early process initialization phase for growsup
configuration.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:12 -07:00
KOSAKI Motohiro 1b79acc911 mm, mem-hotplug: recalculate lowmem_reserve when memory hotplug occurs
Currently, memory hotplug calls setup_per_zone_wmarks() and
calculate_zone_inactive_ratio(), but doesn't call
setup_per_zone_lowmem_reserve().

It means the number of reserved pages aren't updated even if memory hot
plug occur.  This patch fixes it.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:09 -07:00
KOSAKI Motohiro 37b23e0525 x86,mm: make pagefault killable
When an oom killing occurs, almost all processes are getting stuck at the
following two points.

	1) __alloc_pages_nodemask
	2) __lock_page_or_retry

1) is not very problematic because TIF_MEMDIE leads to an allocation
failure and getting out from page allocator.

2) is more problematic.  In an OOM situation, zones typically don't have
page cache at all and memory starvation might lead to greatly reduced IO
performance.  When a fork bomb occurs, TIF_MEMDIE tasks don't die quickly,
meaning that a fork bomb may create new process quickly rather than the
oom-killer killing it.  Then, the system may become livelocked.

This patch makes the pagefault interruptible by SIGKILL.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-25 08:39:08 -07:00