First remove items from work_list as soon as we start working on them.  This
means we don't have to track any pending or visited state and can get
rid of all the RCU magic freeing the work items - we can simply free
them once the operation has finished.  Second use a real completion for
tracking synchronous requests - if the caller sets the completion pointer
we complete it, otherwise use it as a boolean indicator that we can free
the work item directly.  Third unify struct wb_writeback_args and struct
bdi_work into a single data structure, wb_writeback_work.  Previous we
set all parameters into a struct wb_writeback_args, copied it into
struct bdi_work, copied it again on the stack to use it there.  Instead
of just allocate one structure dynamically or on the stack and use it
all the way through the stack.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

This was just an odd wrapper around writeback_inodes_wb.  Removing this
also allows to get rid of the bdi member of struct writeback_control
which was rather out of place there.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

My patch to "Factor out duplicate put/frees in mpol_shared_policy_init()
to a common return path"; and Dan Carpenter's fix thereto both left a
dangling reference to the incoming tmpfs superblock mempolicy structure.
A similar leak was introduced earlier when the nodemask was moved offstack
to the scratch area despite the note in the comment block regarding the
incoming ref.

Move the remaining 'put of the incoming "mpol" to the common exit path to
drop the reference.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: NDan Carpenter <error27@gmail.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

OOM-waitqueue should be waken up when oom_disable is canceled.  This is a
fix for 3c11ecf4 ("memcg: oom kill disable and oom status").

How to test:
 Create a cgroup A...
 1. set memory.limit and memory.memsw.limit to be small value
 2. echo 1 > /cgroup/A/memory.oom_control, this disables oom-kill.
 3. run a program which must cause OOM.

A program executed in 3 will sleep by oom_waiqueue in memcg.  Then, how to
wake it up is problem.

 1. echo 0 > /cgroup/A/memory.oom_control (enable OOM-killer)
 2. echo big mem > /cgroup/A/memory.memsw.limit_in_bytes(allow more swap)

etc..

Without the patch, a task in slept can not be waken up.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

per_cpu_ptr_to_phys() determines whether the passed in @addr belongs
to the first_chunk or not by just matching the address against the
address range of the base unit (unit0, used by cpu0).  When an adress
from another cpu was passed in, it will always determine that the
address doesn't belong to the first chunk even when it does.  This
makes the function return a bogus physical address which may lead to
crash.

This problem was discovered by Cliff Wickman while investigating a
crash during kdump on a SGI UV system.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NCliff Wickman <cpw@sgi.com>
Tested-by: NCliff Wickman <cpw@sgi.com>
Cc: stable@kernel.org

Fix the following two trivial bugs in pcpu_build_alloc_info()

* we should memset group_cnt to 0 by size of group_cnt, not size of
  group_map (both are of the same size, so the bug isn't dangerous)

* we can delete useless variable group_cnt_max.
Signed-off-by: NPavel V. Panteleev <pp_84@mail.ru>
Signed-off-by: NTejun Heo <tj@kernel.org>

bdi_start_writeback now never gets a superblock passed, so we can just remove
that case.  And to further untangle the code and flatten the call stack
split it into two trivial helpers for it's two callers.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

sync can currently take a really long time if a concurrent writer is
extending a file. The problem is that the dirty pages on the address
space grow in the same direction as write_cache_pages scans, so if
the writer keeps ahead of writeback, the writeback will not
terminate until the writer stops adding dirty pages.

For a data integrity sync, we only need to write the pages dirty at
the time we start the writeback, so we can stop scanning once we get
to the page that was at the end of the file at the time the scan
started.

This will prevent operations like copying a large file preventing
sync from completing as it will not write back pages that were
dirtied after the sync was started. This does not impact the
existing integrity guarantees, as any dirty page (old or new)
within the EOF range at the start of the scan will still be
captured.

This patch will not prevent sync from blocking on large writes into
holes. That requires more complex intervention while this patch only
addresses the common append-case of this sync holdoff.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If a filesystem writes more than one page in ->writepage, write_cache_pages
fails to notice this and continues to attempt writeback when wbc->nr_to_write
has gone negative - this trace was captured from XFS:

    wbc_writeback_start: towrt=1024
    wbc_writepage: towrt=1024
    wbc_writepage: towrt=0
    wbc_writepage: towrt=-1
    wbc_writepage: towrt=-5
    wbc_writepage: towrt=-21
    wbc_writepage: towrt=-85

This has adverse effects on filesystem writeback behaviour. write_cache_pages()
needs to terminate after a certain number of pages are written, not after a
certain number of calls to ->writepage are made.  This is a regression
introduced by 17bc6c30 ("vfs: Add
no_nrwrite_index_update writeback control flag"), but cannot be reverted
directly due to subsequent bug fixes that have gone in on top of it.
Signed-off-by: NDave Chinner <dchinner@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Greg Thelen reported recent Johannes's stack diet patch makes kernel hang.
 His test is following.

  mount -t cgroup none /cgroups -o memory
  mkdir /cgroups/cg1
  echo $$ > /cgroups/cg1/tasks
  dd bs=1024 count=1024 if=/dev/null of=/data/foo
  echo $$ > /cgroups/tasks
  echo 1 > /cgroups/cg1/memory.force_empty

Actually, This OOM hard to try logic have been corrupted since following
two years old patch.

	commit a41f24ea
	Author: Nishanth Aravamudan <nacc@us.ibm.com>
	Date:   Tue Apr 29 00:58:25 2008 -0700

	    page allocator: smarter retry of costly-order allocations

Original intention was "return success if the system have shrinkable zones
though priority==0 reclaim was failure".  But the above patch changed to
"return nr_reclaimed if .....".  Oh, That forgot nr_reclaimed may be 0 if
priority==0 reclaim failure.

And Johannes's patch 0aeb2339 ("vmscan: remove all_unreclaimable scan
control") made it more corrupt.  Originally, priority==0 reclaim failure
on memcg return 0, but this patch changed to return 1.  It totally
confused memcg.

This patch fixes it completely.
Reported-by: NGreg Thelen <gthelen@google.com>
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: NGreg Thelen <gthelen@google.com>
Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mtime and ctime should be changed only if the file size has actually
changed. Patches changing ext2 and tmpfs from vmtruncate to new truncate
sequence has caused regressions where they always update timestamps.

There is some strange cases in POSIX where truncate(2) must not update
times unless the size has acutally changed, see 6e656be8.

This area is all still rather buggy in different ways in a lot of
filesystems and needs a cleanup and audit (ideally the vfs will provide
a simple attribute or call to direct all filesystems exactly which
attributes to change). But coming up with the best solution will take a
while and is not appropriate for rc anyway.

So fix recent regression for now.
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This reverts commit e913fc82.

We are investigating a hang associated with the WB_SYNC_NONE changes,
so revert them for now.

Conflicts:

	fs/fs-writeback.c
	mm/page-writeback.c
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

Cc: Christoph Hellwig <hch@lst.de>
Acked-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Introduce a new truncate calling sequence into fs/mm subsystems. Rather than
setattr > vmtruncate > truncate, have filesystems call their truncate sequence
from ->setattr if filesystem specific operations are required. vmtruncate is
deprecated, and truncate_pagecache and inode_newsize_ok helpers introduced
previously should be used.

simple_setattr is introduced for simple in-ram filesystems to implement
the new truncate sequence. Eventually all filesystems should be converted
to implement a setattr, and the default code in notify_change should go
away.

simple_setsize is also introduced to perform just the ATTR_SIZE portion
of simple_setattr (ie. changing i_size and trimming pagecache).

To implement the new truncate sequence:
- filesystem specific manipulations (eg freeing blocks) must be done in
  the setattr method rather than ->truncate.
- vmtruncate can not be used by core code to trim blocks past i_size in
  the event of write failure after allocation, so this must be performed
  in the fs code.
- convert usage of helpers block_write_begin, nobh_write_begin,
  cont_write_begin, and *blockdev_direct_IO* to use _newtrunc postfixed
  variants. These avoid calling vmtruncate to trim blocks (see previous).
- inode_setattr should not be used. generic_setattr is a new function
  to be used to copy simple attributes into the generic inode.
- make use of the better opportunity to handle errors with the new sequence.

Big problem with the previous calling sequence: the filesystem is not called
until i_size has already changed.  This means it is not allowed to fail the
call, and also it does not know what the previous i_size was. Also, generic
code calling vmtruncate to truncate allocated blocks in case of error had
no good way to return a meaningful error (or, for example, atomically handle
block deallocation).

Cc: Christoph Hellwig <hch@lst.de>
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NNick Piggin <npiggin@suse.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

We don't name our generic fsync implementations very well currently.
The no-op implementation for in-memory filesystems currently is called
simple_sync_file which doesn't make too much sense to start with,
the the generic one for simple filesystems is called simple_fsync
which can lead to some confusion.

This patch renames the generic file fsync method to generic_file_fsync
to match the other generic_file_* routines it is supposed to be used
with, and the no-op implementation to noop_fsync to make it obvious
what to expect.  In addition add some documentation for both methods.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Example usage of generic "numa_mem_id()":

The mainline slab code, since ~ 2.6.19, does not handle memoryless nodes
well.  Specifically, the "fast path"--____cache_alloc()--will never
succeed as slab doesn't cache offnode object on the per cpu queues, and
for memoryless nodes, all memory will be "off node" relative to
numa_node_id().  This adds significant overhead to all kmem cache
allocations, incurring a significant regression relative to earlier
kernels [from before slab.c was reorganized].

This patch uses the generic topology function "numa_mem_id()" to return
the "effective local memory node" for the calling context.  This is the
first node in the local node's generic fallback zonelist-- the same node
that "local" mempolicy-based allocations would use.  This lets slab cache
these "local" allocations and avoid fallback/refill on every allocation.

N.B.: Slab will need to handle node and memory hotplug events that could
change the value returned by numa_mem_id() for any given node if recent
changes to address memory hotplug don't already address this.  E.g., flush
all per cpu slab queues before rebuilding the zonelists while the
"machine" is held in the stopped state.

Performance impact on "hackbench 400 process 200"

2.6.34-rc3-mmotm-100405-1609		no-patch	this-patch
ia64 no memoryless nodes [avg of 10]:     11.713       11.637  ~0.65 diff
ia64 cpus all on memless nodes  [10]:    228.259       26.484  ~8.6x speedup

The slowdown of the patched kernel from ~12 sec to ~28 seconds when
configured with memoryless nodes is the result of all cpus allocating from
a single node's mm pagepool.  The cache lines of the single node are
distributed/interleaved over the memory of the real physical nodes, but
the zone lock, list heads, ...  of the single node with memory still each
live in a single cache line that is accessed from all processors.

x86_64 [8x6 AMD] [avg of 40]:		2.883	   2.845
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce numa_mem_id(), based on generic percpu variable infrastructure
to track "nearest node with memory" for archs that support memoryless
nodes.

Define API in <linux/topology.h> when CONFIG_HAVE_MEMORYLESS_NODES
defined, else stubs.  Architectures will define HAVE_MEMORYLESS_NODES
if/when they support them.

Archs can override definitions of:

numa_mem_id() - returns node number of "local memory" node
set_numa_mem() - initialize [this cpus'] per cpu variable 'numa_mem'
cpu_to_mem()  - return numa_mem for specified cpu; may be used as lvalue

Generic initialization of 'numa_mem' occurs in __build_all_zonelists().
This will initialize the boot cpu at boot time, and all cpus on change of
numa_zonelist_order, or when node or memory hot-plug requires zonelist
rebuild.  Archs that support memoryless nodes will need to initialize
'numa_mem' for secondary cpus as they're brought on-line.

[akpm@linux-foundation.org: fix build]
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Rework the generic version of the numa_node_id() function to use the new
generic percpu variable infrastructure.

Guard the new implementation with a new config option:

        CONFIG_USE_PERCPU_NUMA_NODE_ID.

Archs which support this new implemention will default this option to 'y'
when NUMA is configured.  This config option could be removed if/when all
archs switch over to the generic percpu implementation of numa_node_id().
Arch support involves:

  1) converting any existing per cpu variable implementations to use
     this implementation.  x86_64 is an instance of such an arch.
  2) archs that don't use a per cpu variable for numa_node_id() will
     need to initialize the new per cpu variable "numa_node" as cpus
     are brought on-line.  ia64 is an example.
  3) Defining USE_PERCPU_NUMA_NODE_ID in arch dependent Kconfig--e.g.,
     when NUMA is configured.  This is required because I have
     retained the old implementation by default to allow archs to
     be modified incrementally, as desired.

Subsequent patches will convert x86_64 and ia64 to use this implemenation.
Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

By the previous modification, the cpu notifier can return encapsulate
errno value.  This converts the cpu notifiers for slab.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have observed several workloads running on multi-node systems where
memory is assigned unevenly across the nodes in the system.  There are
numerous reasons for this but one is the round-robin rotor in
cpuset_mem_spread_node().

For example, a simple test that writes a multi-page file will allocate
pages on nodes 0 2 4 6 ...  Odd nodes are skipped.  (Sometimes it
allocates on odd nodes & skips even nodes).

An example is shown below.  The program "lfile" writes a file consisting
of 10 pages.  The program then mmaps the file & uses get_mempolicy(...,
MPOL_F_NODE) to determine the nodes where the file pages were allocated.
The output is shown below:

	# ./lfile
	 allocated on nodes: 2 4 6 0 1 2 6 0 2

There is a single rotor that is used for allocating both file pages & slab
pages.  Writing the file allocates both a data page & a slab page
(buffer_head).  This advances the RR rotor 2 nodes for each page
allocated.

A quick confirmation seems to confirm this is the cause of the uneven
allocation:

	# echo 0 >/dev/cpuset/memory_spread_slab
	# ./lfile
	 allocated on nodes: 6 7 8 9 0 1 2 3 4 5

This patch introduces a second rotor that is used for slab allocations.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Acked-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Paul Menage <menage@google.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Introduce struct mem_cgroup_thresholds.  It helps to reduce number of
checks of thresholds type (memory or mem+swap).

[akpm@linux-foundation.org: repair comment]
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NPaul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since we are unable to handle an error returned by
cftype.unregister_event() properly, let's make the callback
void-returning.

mem_cgroup_unregister_event() has been rewritten to be a "never fail"
function.  On mem_cgroup_usage_register_event() we save old buffer for
thresholds array and reuse it in mem_cgroup_usage_unregister_event() to
avoid allocation.
Signed-off-by: NKirill A. Shutemov <kirill@shutemov.name>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

FILE_MAPPED per memcg of migrated file cache is not properly updated,
because our hook in page_add_file_rmap() can't know to which memcg
FILE_MAPPED should be counted.

Basically, this patch is for fixing the bug but includes some big changes
to fix up other messes.

Now, at migrating mapped file, events happen in following sequence.

 1. allocate a new page.
 2. get memcg of an old page.
 3. charge ageinst a new page before migration. But at this point,
    no changes to new page's page_cgroup, no commit for the charge.
    (IOW, PCG_USED bit is not set.)
 4. page migration replaces radix-tree, old-page and new-page.
 5. page migration remaps the new page if the old page was mapped.
 6. Here, the new page is unlocked.
 7. memcg commits the charge for newpage, Mark the new page's page_cgroup
    as PCG_USED.

Because "commit" happens after page-remap, we can count FILE_MAPPED
at "5", because we should avoid to trust page_cgroup->mem_cgroup.
if PCG_USED bit is unset.
(Note: memcg's LRU removal code does that but LRU-isolation logic is used
 for helping it. When we overwrite page_cgroup->mem_cgroup, page_cgroup is
 not on LRU or page_cgroup->mem_cgroup is NULL.)

We can lose file_mapped accounting information at 5 because FILE_MAPPED
is updated only when mapcount changes 0->1. So we should catch it.

BTW, historically, above implemntation comes from migration-failure
of anonymous page. Because we charge both of old page and new page
with mapcount=0, we can't catch
  - the page is really freed before remap.
  - migration fails but it's freed before remap
or .....corner cases.

New migration sequence with memcg is:

 1. allocate a new page.
 2. mark PageCgroupMigration to the old page.
 3. charge against a new page onto the old page's memcg. (here, new page's pc
    is marked as PageCgroupUsed.)
 4. page migration replaces radix-tree, page table, etc...
 5. At remapping, new page's page_cgroup is now makrked as "USED"
    We can catch 0->1 event and FILE_MAPPED will be properly updated.

    And we can catch SWAPOUT event after unlock this and freeing this
    page by unmap() can be caught.

 7. Clear PageCgroupMigration of the old page.

So, FILE_MAPPED will be correctly updated.

Then, for what MIGRATION flag is ?
  Without it, at migration failure, we may have to charge old page again
  because it may be fully unmapped. "charge" means that we have to dive into
  memory reclaim or something complated. So, it's better to avoid
  charge it again. Before this patch, __commit_charge() was working for
  both of the old/new page and fixed up all. But this technique has some
  racy condtion around FILE_MAPPED and SWAPOUT etc...
  Now, the kernel use MIGRATION flag and don't uncharge old page until
  the end of migration.

I hope this change will make memcg's page migration much simpler.  This
page migration has caused several troubles.  Worth to add a flag for
simplification.
Reviewed-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Tested-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Only an out of memory error will cause ret to be set.
Signed-off-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: NKirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The bottom 4 hunks are atomically changing memory to which there are no
aliases as it's freshly allocated, so there's no need to use atomic
operations.

The other hunks are just atomic_read and atomic_set, and do not involve
any read-modify-write.  The use of atomic_{read,set} doesn't prevent a
read/write or write/write race, so if a race were possible (I'm not saying
one is), then it would still be there even with atomic_set.

See:
http://digitalvampire.org/blog/index.php/2007/05/13/atomic-cargo-cults/Signed-off-by: NPhil Carmody <ext-phil.2.carmody@nokia.com>
Acked-by: NKirill A. Shutemov <kirill@shutemov.name>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's pointless to try to kill current if select_bad_process() did not find
an eligible task to kill in mem_cgroup_out_of_memory() since it's
guaranteed that current is a member of the memcg that is oom and it is, by
definition, unkillable.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch adds support for moving charge of file pages, which include
normal file, tmpfs file and swaps of tmpfs file.  It's enabled by setting
bit 1 of <target cgroup>/memory.move_charge_at_immigrate.

Unlike the case of anonymous pages, file pages(and swaps) in the range
mmapped by the task will be moved even if the task hasn't done page fault,
i.e.  they might not be the task's "RSS", but other task's "RSS" that maps
the same file.  And mapcount of the page is ignored(the page can be moved
even if page_mapcount(page) > 1).  So, conditions that the page/swap
should be met to be moved is that it must be in the range mmapped by the
target task and it must be charged to the old cgroup.

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix warning]
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch cleans up move charge code by:

- define functions to handle pte for each types, and make
  is_target_pte_for_mc() cleaner.

- instead of checking the MOVE_CHARGE_TYPE_ANON bit, define a function
  that checks the bit.
Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds a feature to disable oom-killer for memcg, if disabled, of
course, tasks under memcg will stop.

But now, we have oom-notifier for memcg.  And the world around memcg is
not under out-of-memory.  memcg's out-of-memory just shows memcg hits
limit.  Then, administrator or management daemon can recover the situation
by

	- kill some process
	- enlarge limit, add more swap.
	- migrate some tasks
	- remove file cache on tmps (difficult ?)

Unlike oom-killer, you can take enough information before killing tasks.
(by gcore, or, ps etc.)

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Considering containers or other resource management softwares in userland,
event notification of OOM in memcg should be implemented.  Now, memcg has
"threshold" notifier which uses eventfd, we can make use of it for oom
notification.

This patch adds oom notification eventfd callback for memcg.  The usage is
very similar to threshold notifier, but control file is memory.oom_control
and no arguments other than eventfd is required.

	% cgroup_event_notifier /cgroup/A/memory.oom_control dummy
	(About cgroup_event_notifier, see Documentation/cgroup/)
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memcg's oom waitqueue is a system-wide wait_queue (for handling
hierarchy.) So, it's better to add custom wake function and do filtering
in wake up path.

This patch adds a filtering feature for waking up oom-waiters.  Hierarchy
is properly handled.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I/O errors can happen due to temporary failures, like multipath
errors or losing network contact with the iSCSI server. Because
of that, the VM will retry readpage on the page.

However, do_generic_file_read does not clear PG_error.  This
causes the system to be unable to actually use the data in the
page cache page, even if the subsequent readpage completes
successfully!

The function filemap_fault has had a ClearPageError before
readpage forever.  This patch simply adds the same to
do_generic_file_read.
Signed-off-by: NJeff Moyer <jmoyer@redhat.com>
Signed-off-by: NRik van Riel <riel@redhat.com>
Acked-by: NLarry Woodman <lwoodman@redhat.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Slightly rearrange the logic that determines capabilities and vm_flags.
Disable BDI_CAP_MAP_DIRECT in all cases if the device can't support the
protections.  Allow private readonly mappings of readonly backing devices.
Signed-off-by: NBernd Schmidt <bernds_cb1@t-online.de>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Acked-by: NDavid McCullough <davidm@snapgear.com>
Acked-by: NGreg Ungerer <gerg@uclinux.org>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NDavid Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The original code called mpol_put(new) while "new" was an ERR_PTR.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add global mutex zonelists_mutex to fix the possible race:

     CPU0                                  CPU1                    CPU2
(1) zone->present_pages += online_pages;
(2)                                       build_all_zonelists();
(3)                                                               alloc_page();
(4)                                                               free_page();
(5) build_all_zonelists();
(6)   __build_all_zonelists();
(7)     zone->pageset = alloc_percpu();

In step (3,4), zone->pageset still points to boot_pageset, so bad
things may happen if 2+ nodes are in this state. Even if only 1 node
is accessing the boot_pageset, (3) may still consume too much memory
to fail the memory allocations in step (7).

Besides, atomic operation ensures alloc_percpu() in step (7) will never fail
since there is a new fresh memory block added in step(6).

[haicheng.li@linux.intel.com: hold zonelists_mutex when build_all_zonelists]
Signed-off-by: NHaicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Reviewed-by: NAndi Kleen <andi.kleen@intel.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For each new populated zone of hotadded node, need to update its pagesets
with dynamically allocated per_cpu_pageset struct for all possible CPUs:

    1) Detach zone->pageset from the shared boot_pageset
       at end of __build_all_zonelists().

    2) Use mutex to protect zone->pageset when it's still
       shared in onlined_pages()

Otherwises, multiple zones of different nodes would share same boot strapping
boot_pageset for same CPU, which will finally cause below kernel panic:

  ------------[ cut here ]------------
  kernel BUG at mm/page_alloc.c:1239!
  invalid opcode: 0000 [#1] SMP
  ...
  Call Trace:
   [<ffffffff811300c1>] __alloc_pages_nodemask+0x131/0x7b0
   [<ffffffff81162e67>] alloc_pages_current+0x87/0xd0
   [<ffffffff81128407>] __page_cache_alloc+0x67/0x70
   [<ffffffff811325f0>] __do_page_cache_readahead+0x120/0x260
   [<ffffffff81132751>] ra_submit+0x21/0x30
   [<ffffffff811329c6>] ondemand_readahead+0x166/0x2c0
   [<ffffffff81132ba0>] page_cache_async_readahead+0x80/0xa0
   [<ffffffff8112a0e4>] generic_file_aio_read+0x364/0x670
   [<ffffffff81266cfa>] nfs_file_read+0xca/0x130
   [<ffffffff8117b20a>] do_sync_read+0xfa/0x140
   [<ffffffff8117bf75>] vfs_read+0xb5/0x1a0
   [<ffffffff8117c151>] sys_read+0x51/0x80
   [<ffffffff8103c032>] system_call_fastpath+0x16/0x1b
  RIP  [<ffffffff8112ff13>] get_page_from_freelist+0x883/0x900
   RSP <ffff88000d1e78a8>
  ---[ end trace 4bda28328b9990db ]

[akpm@linux-foundation.org: merge fix]
Signed-off-by: NHaicheng Li <haicheng.li@linux.intel.com>
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Reviewed-by: NAndi Kleen <andi.kleen@intel.com>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

No behavior change here.

Move some of setup_per_cpu_pageset() code into a new function
setup_zone_pageset() that will be useful for memory hotplug.
Signed-off-by: NWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: NHaicheng Li <haicheng.li@linux.intel.com>
Reviewed-by: NAndi Kleen <andi.kleen@intel.com>
Reviewed-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In f4112de6 ("mm: introduce
debug_kmap_atomic") I said that debug_kmap_atomic() needs
CONFIG_TRACE_IRQFLAGS_SUPPORT.

It was wrong.  (I thought irqs_disabled() is only available when the
architecture has CONFIG_TRACE_IRQFLAGS_SUPPORT)

Remove the #ifdef CONFIG_TRACE_IRQFLAGS_SUPPORT check to enable
kmap_atomic() debugging for the architectures which do not have
CONFIG_TRACE_IRQFLAGS_SUPPORT.
Reported-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Enable users to online CPUs even if the CPUs belongs to a numa node which
doesn't have onlined local memory.

The zonlists(pg_data_t.node_zonelists[]) of a numa node are created either
in system boot/init period, or at the time of local memory online.  For a
numa node without onlined local memory, its zonelists are not initialized
at present.  As a result, any memory allocation operations executed by
CPUs within this node will fail.  In fact, an out-of-memory error is
triggered when attempt to online CPUs before memory comes to online.

This patch tries to create zonelists for such numa nodes, so that the
memory allocation for this node can be fallback'ed to other nodes.

[akpm@linux-foundation.org: remove unneeded export]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: minskey guo<chaohong.guo@intel.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For now, we have global isolation vs.  memory control group isolation, do
not allow the reclaim entry function to set an arbitrary page isolation
callback, we do not need that flexibility.

And since we already pass around the group descriptor for the memory
control group isolation case, just use it to decide which one of the two
isolator functions to use.

The decisions can be merged into nearby branches, so no extra cost there.
In fact, we save the indirect calls.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>