Michael Leun reported that running parallel opens on a fuse filesystem
can trigger a "kernel BUG at mm/truncate.c:475"

Gurudas Pai reported the same bug on NFS.

The reason is, unmap_mapping_range() is not prepared for more than
one concurrent invocation per inode.  For example:

  thread1: going through a big range, stops in the middle of a vma and
     stores the restart address in vm_truncate_count.

  thread2: comes in with a small (e.g. single page) unmap request on
     the same vma, somewhere before restart_address, finds that the
     vma was already unmapped up to the restart address and happily
     returns without doing anything.

Another scenario would be two big unmap requests, both having to
restart the unmapping and each one setting vm_truncate_count to its
own value.  This could go on forever without any of them being able to
finish.

Truncate and hole punching already serialize with i_mutex.  Other
callers of unmap_mapping_range() do not, and it's difficult to get
i_mutex protection for all callers.  In particular ->d_revalidate(),
which calls invalidate_inode_pages2_range() in fuse, may be called
with or without i_mutex.

This patch adds a new mutex to 'struct address_space' to prevent
running multiple concurrent unmap_mapping_range() on the same mapping.

[ We'll hopefully get rid of all this with the upcoming mm
  preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex
  lockbreak" patch in particular.  But that is for 2.6.39 ]
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>
Reported-by: NMichael Leun <lkml20101129@newton.leun.net>
Reported-by: NGurudas Pai <gurudas.pai@oracle.com>
Tested-by: NGurudas Pai <gurudas.pai@oracle.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Transparent hugepages can only be created if rmap is fully
functional. So we must prevent hugepages to be created while
is_vma_temporary_stack() is true.

This also optmizes away some harmless but unnecessary setting of
khugepaged_scan.address and it switches some BUG_ON to VM_BUG_ON.
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mem_cgroup_uncharge_page() should be called in all failure cases after
mem_cgroup_charge_newpage() is called in huge_memory.c::collapse_huge_page()

 [ 4209.076861] BUG: Bad page state in process khugepaged  pfn:1e9800
 [ 4209.077601] page:ffffea0006b14000 count:0 mapcount:0 mapping:          (null) index:0x2800
 [ 4209.078674] page flags: 0x40000000004000(head)
 [ 4209.079294] pc:ffff880214a30000 pc->flags:2146246697418756 pc->mem_cgroup:ffffc9000177a000
 [ 4209.082177] (/A)
 [ 4209.082500] Pid: 31, comm: khugepaged Not tainted 2.6.38-rc3-mm1 #1
 [ 4209.083412] Call Trace:
 [ 4209.083678]  [<ffffffff810f4454>] ? bad_page+0xe4/0x140
 [ 4209.084240]  [<ffffffff810f53e6>] ? free_pages_prepare+0xd6/0x120
 [ 4209.084837]  [<ffffffff8155621d>] ? rwsem_down_failed_common+0xbd/0x150
 [ 4209.085509]  [<ffffffff810f5462>] ? __free_pages_ok+0x32/0xe0
 [ 4209.086110]  [<ffffffff810f552b>] ? free_compound_page+0x1b/0x20
 [ 4209.086699]  [<ffffffff810fad6c>] ? __put_compound_page+0x1c/0x30
 [ 4209.087333]  [<ffffffff810fae1d>] ? put_compound_page+0x4d/0x200
 [ 4209.087935]  [<ffffffff810fb015>] ? put_page+0x45/0x50
 [ 4209.097361]  [<ffffffff8113f779>] ? khugepaged+0x9e9/0x1430
 [ 4209.098364]  [<ffffffff8107c870>] ? autoremove_wake_function+0x0/0x40
 [ 4209.099121]  [<ffffffff8113ed90>] ? khugepaged+0x0/0x1430
 [ 4209.099780]  [<ffffffff8107c236>] ? kthread+0x96/0xa0
 [ 4209.100452]  [<ffffffff8100dda4>] ? kernel_thread_helper+0x4/0x10
 [ 4209.101214]  [<ffffffff8107c1a0>] ? kthread+0x0/0xa0
 [ 4209.101842]  [<ffffffff8100dda0>] ? kernel_thread_helper+0x0/0x10
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 3e7d3449 ("mm: vmscan: reclaim order-0 and use compaction
instead of lumpy reclaim") introduced an indefinite loop in
shrink_zone().

It meant to break out of this loop when no pages had been reclaimed and
not a single page was even scanned.  The way it would detect the latter
is by taking a snapshot of sc->nr_scanned at the beginning of the
function and comparing it against the new sc->nr_scanned after the scan
loop.  But it would re-iterate without updating that snapshot, looping
forever if sc->nr_scanned changed at least once since shrink_zone() was
invoked.

This is not the sole condition that would exit that loop, but it
requires other processes to change the zone state, as the reclaimer that
is stuck obviously can not anymore.

This is only happening for higher-order allocations, where reclaim is
run back to back with compaction.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reported-by: NMichal Hocko <mhocko@suse.cz>
Tested-by: Kent Overstreet<kent.overstreet@gmail.com>
Reported-by: NKent Overstreet <kent.overstreet@gmail.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the page is going to be written to, __do_page needs to break COW.

However, the old page (before breaking COW) was never mapped mapped into
the current pte (__do_fault is only called when the pte is not present),
so vmscan can't have marked the old page as PageMlocked due to being
mapped in __do_fault's VMA.  Therefore, __do_fault() does not need to
worry about clearing PageMlocked() on the old page.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

vmscan can lazily find pages that are mapped within VM_LOCKED vmas, and
set the PageMlocked bit on these pages, transfering them onto the
unevictable list.  When do_wp_page() breaks COW within a VM_LOCKED vma,
it may need to clear PageMlocked on the old page and set it on the new
page instead.

This change fixes an issue where do_wp_page() was clearing PageMlocked
on the old page while the pte was still pointing to it (as well as
rmap).  Therefore, we were not protected against vmscan immediately
transfering the old page back onto the unevictable list.  This could
cause pages to get stranded there forever.

I propose to move the corresponding code to the end of do_wp_page(),
after the pte (and rmap) have been pointed to the new page.
Additionally, we can use munlock_vma_page() instead of
clear_page_mlock(), so that the old page stays mlocked if there are
still other VM_LOCKED vmas mapping it.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While applying patch to use memblock to find aperture for 64bit x86.
Ingo found system with 1g + force_iommu

> No AGP bridge found
> Node 0: aperture @ 38000000 size 32 MB
> Aperture pointing to e820 RAM. Ignoring.
> Your BIOS doesn't leave a aperture memory hole
> Please enable the IOMMU option in the BIOS setup
> This costs you 64 MB of RAM
> Cannot allocate aperture memory hole (0,65536K)

the corresponding code:

	addr = memblock_find_in_range(0, 1ULL<<32, aper_size, 512ULL<<20);
	if (addr == MEMBLOCK_ERROR || addr + aper_size > 0xffffffff) {
		printk(KERN_ERR
			"Cannot allocate aperture memory hole (%lx,%uK)\n",
				addr, aper_size>>10);
		return 0;
	}
	memblock_x86_reserve_range(addr, addr + aper_size, "aperture64")

fails because memblock core code align the size with 512M.  That could
make size way too big.

So don't align the size in that case.

actually __memblock_alloc_base, the another caller already align that
before calling that function.

BTW. x86 does not use __memblock_alloc_base...
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Miller <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Changes in e401f176 ("memcg: modify accounting function for supporting
THP better") adds nr_pages to support multiple page size in
memory_cgroup_charge_statistics.

But counting the number of event nees abs(nr_pages) for increasing
counters.  This patch fixes event counting.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Huge page coverage should obviously have less priority than the continued
execution of a process.

Never kill a process when charging it a huge page fails.  Instead, give up
after the first failed reclaim attempt and fall back to regular pages.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.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>

If reclaim after a failed charging was unsuccessful, the limits are
checked again, just in case they settled by means of other tasks.

This is all fine as long as every charge is of size PAGE_SIZE, because in
that case, being below the limit means having at least PAGE_SIZE bytes
available.

But with transparent huge pages, we may end up in an endless loop where
charging and reclaim fail, but we keep going because the limits are not
yet exceeded, although not allowing for a huge page.

Fix this up by explicitely checking for enough room, not just whether we
are within limits.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.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>

The charging code can encounter a charge size that is bigger than a
regular page in two situations: one is a batched charge to fill the
per-cpu stocks, the other is a huge page charge.

This code is distributed over two functions, however, and only the outer
one is aware of huge pages.  In case the charging fails, the inner
function will tell the outer function to retry if the charge size is
bigger than regular pages--assuming batched charging is the only case.
And the outer function will retry forever charging a huge page.

This patch makes sure the inner function can distinguish between batch
charging and a single huge page charge.  It will only signal another
attempt if batch charging failed, and go into regular reclaim when it is
called on behalf of a huge page.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.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>

When a tail page of THP is poisoned, memory-failure will do nothing except
setting PG_hwpoison, while the expected behavior is that the process, who
is using the poisoned tail page, should be killed.

The above problem is caused by lru check of the poisoned tail page of THP.
Because PG_lru flag is only set on the head page of THP, the check always
consider the poisoned tail page as NON lru page.

So the lru check for the tail page of THP should be avoided, as like as
hugetlb.

This patch adds !PageTransCompound() before lru check for THP, because of
the check (!PageHuge() && !PageTransCompound()) the whole branch could be
optimized away at build time when both hugetlbfs and THP are set with "N"
(or in archs not supporting either of those).

[akpm@linux-foundation.org: fix unrelated typo in shake_page() comment]
Signed-off-by: NJin Dongming <jin.dongming@np.css.fujitsu.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the tail page of THP is poisoned, the head page will be poisoned too.
 And the wrong address, address of head page, will be sent with sigbus
always.

So when the poisoned page is used by Guest OS which is running on KVM,
after the address changing(hva->gpa) by qemu, the unexpected process on
Guest OS will be killed by sigbus.

What we expected is that the process using the poisoned tail page could be
killed on Guest OS, but not that the process using the healthy head page
is killed.

Since it is not good to poison the healthy page, avoid poisoning other
than the page which is really poisoned.
  (While we poison all pages in a huge page in case of hugetlb,
   we can do this for THP thanks to split_huge_page().)

Here we fix two parts:
  1. Isolate the poisoned page only to make sure
     the reported address is the address of poisoned page.
  2. make the poisoned page work as the poisoned regular page.

[akpm@linux-foundation.org: fix spello in comment]
Signed-off-by: NJin Dongming <jin.dongming@np.css.fujitsu.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The poisoned THP is now split with split_huge_page() in
collect_procs_anon().  If kmalloc() is failed in collect_procs(),
split_huge_page() could not be called.  And the work after
split_huge_page() for collecting the processes using poisoned page will
not be done, too.  So the processes using the poisoned page could not be
killed.

The condition becomes worse when CONFIG_DEBUG_VM == "Y".  Because the
poisoned THP could not be split, system panic will be caused by
VM_BUG_ON(PageTransHuge(page)) in try_to_unmap().

This patch does:
  1. move split_huge_page() to the place before collect_procs().
     This can be sure the failure of splitting THP is caused by itself.
  2. when splitting THP is failed, stop the operations after it.
     This can avoid unexpected system panic or non sense works.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NJin Dongming <jin.dongming@np.css.fujitsu.com>
Reviewed-by: NHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If migrate_huge_page by memory-failure fails , it calls put_page in itself
to decrease page reference and caller of migrate_huge_page also calls
putback_lru_pages.  It can do double free of page so it can make page
corruption on page holder.

In addtion, clean of pages on caller is consistent behavior with
migrate_pages by cf608ac1 ("mm: compaction: fix COMPACTPAGEFAILED
counting").
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In some cases migrate_pages could return zero while still leaving a few
pages in the pagelist (and some caller wouldn't notice it has to call
putback_lru_pages after commit cf608ac1 ("mm: compaction: fix
COMPACTPAGEFAILED counting")).

Add one missing putback_lru_pages not added by commit cf608ac1 ("mm:
compaction: fix COMPACTPAGEFAILED counting").
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Acked-by: NMel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

noswapaccount couldn't be used to control memsw for both on/off cases so
we have added swapaccount[=0|1] parameter.  This way we can turn the
feature in two ways noswapaccount resp.  swapaccount=0.  We have kept the
original noswapaccount but I think we should remove it after some time as
it just makes more command line parameters without any advantages and also
the code to handle parameters is uglier if we want both parameters.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Requested-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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>

__setup based kernel command line parameters handlers which are handled in
obsolete_checksetup are provided with the parameter value including =
(more precisely everything right after the parameter name).

This means that the current implementation of swapaccount[=1|0] doesn't
work at all because if there is a value for the parameter then we are
testing for "0" resp.  "1" but we are getting "=0" resp.  "=1" and if
there is no parameter value we are getting an empty string rather than
NULL.

The original noswapccount parameter, which doesn't care about the value,
works correctly.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As Tao Ma noticed, change 5ecfda04 breaks blktrace. This is because
blktrace mmaps a file with PROT_WRITE permissions but without PROT_READ,
so my attempt to not unnecessarity break COW during mlock ended up
causing mlock to fail with a permission problem.

I am proposing to let mlock ignore vma protection in all cases except
PROT_NONE. In particular, mlock should not fail for PROT_WRITE regions
(as in the blktrace case, which broke at 5ecfda04) or for PROT_EXEC
regions (which seem to me like they were always broken).
Signed-off-by: NMichel Lespinasse <walken@google.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch adds __GFP_NORETRY and __GFP_NOMEMALLOC flags to the kmemleak
metadata allocations so that it has a smaller effect on the users of the
kernel slab allocator. Since kmemleak allocations can now fail more
often, this patch also reduces the verbosity by passing __GFP_NOWARN and
not dumping the stack trace when a kmemleak allocation fails.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Reported-by: NToralf Förster <toralf.foerster@gmx.de>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Ted Ts'o <tytso@mit.edu>

We don't need to memset if we just use kzalloc() rather than kmalloc() in
kmemleak_test_init().
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Reviewed-by: NMinchan Kim <minchan.kim@gmail.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>

A fix up mem_cgroup_move_parent() which use compound_order() in
asynchronous manner.  This compound_order() may return unknown value
because we don't take lock.  Use PageTransHuge() and HPAGE_SIZE instead
of it.

Also clean up for mem_cgroup_move_parent().
 - remove unnecessary initialization of local variable.
 - rename charge_size -> page_size
 - remove unnecessary (wrong) comment.
 - added a comment about THP.

Note:
 Current design take compound_page_lock() in caller of move_account().
 This should be revisited when we implement direct move_task of hugepage
 without splitting.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
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>

mem_cgroup_disabled() should be checked at splitting.  If disabled, no
heavy work is necesary.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
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>

Commit 4b534334 ("memcg: clean up try_charge main loop") removes a
cancel of charge at case: memory charge-> success.  mem+swap charge->
failure.

This leaks usage of memory.  Fix it.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: <stable@kernel.org>	[2.6.36+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Callers of migrate_pages should putback_lru_pages to return pages
isolated to LRU or free list.  Now comment is rather confusing.  It says
caller always have to call it.

It is more clear to point out that the caller has to call it if
migrate_pages's return value isn't zero.
Signed-off-by: NMinchan Kim <minchan.kim@gmail.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 5d689240 ("thp: select CONFIG_COMPACTION if TRANSPARENT_HUGEPAGE
enabled") causes this warning during the configuration process:

  warning: (TRANSPARENT_HUGEPAGE) selects COMPACTION which has unmet
  direct dependencies (EXPERIMENTAL && HUGETLB_PAGE && MMU)

COMPACTION doesn't depend on HUGETLB_PAGE, it doesn't depend on THP
either, it is also useful for regular alloc_pages(order > 0) including
the very kernel stack during fork (THREAD_ORDER = 1).  It's always
better to enable COMPACTION.

The warning should be an error because we would end up with MIGRATION
not selected, and COMPACTION wouldn't work without migration (despite it
seems to build with an inline migrate_pages returning -ENOSYS).

I'd also like to remove EXPERIMENTAL: compaction has been in the kernel
for some releases (for full safety the default remains disabled which I
think is enough).
Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
Reported-by: NLuca Tettamanti <kronos.it@gmail.com>
Tested-by: NLuca Tettamanti <kronos.it@gmail.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In mm/memcontrol.c::mem_cgroup_move_parent() there's a path that jumps
to the 'put_back' label

  	ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, charge);
  	if (ret || !parent)
  		goto put_back;

where we'll

  	if (charge > PAGE_SIZE)
  		compound_unlock_irqrestore(page, flags);

but, we have not assigned anything to 'flags' at this point, nor have we
called 'compound_lock_irqsave()' (which is what sets 'flags').  The
'put_back' label should be moved below the call to
compound_unlock_irqrestore() as per this patch.
Signed-off-by: NJesper Juhl <jj@chaosbits.net>
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>
Cc: Pavel Emelianov <xemul@openvz.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>

Commit 0e093d99 ("writeback: do not sleep on the congestion queue if
there are no congested BDIs or if significant congestion is not being
encountered in the current zone") uncovered a livelock in the page
allocator that resulted in tasks infinitely looping trying to find
memory and kswapd running at 100% cpu.

The issue occurs because drain_all_pages() is called immediately
following direct reclaim when no memory is freed and try_to_free_pages()
returns non-zero because all zones in the zonelist do not have their
all_unreclaimable flag set.

When draining the per-cpu pagesets back to the buddy allocator for each
zone, the zone->pages_scanned counter is cleared to avoid erroneously
setting zone->all_unreclaimable later.  The problem is that no pages may
actually be drained and, thus, the unreclaimable logic never fails
direct reclaim so the oom killer may be invoked.

This apparently only manifested after wait_iff_congested() was
introduced and the zone was full of anonymous memory that would not
congest the backing store.  The page allocator would infinitely loop if
there were no other tasks waiting to be scheduled and clear
zone->pages_scanned because of drain_all_pages() as the result of this
change before kswapd could scan enough pages to trigger the reclaim
logic.  Additionally, with every loop of the page allocator and in the
reclaim path, kswapd would be kicked and would end up running at 100%
cpu.  In this scenario, current and kswapd are all running continuously
with kswapd incrementing zone->pages_scanned and current clearing it.

The problem is even more pronounced when current swaps some of its
memory to swap cache and the reclaimable logic then considers all active
anonymous memory in the all_unreclaimable logic, which requires a much
higher zone->pages_scanned value for try_to_free_pages() to return zero
that is never attainable in this scenario.

Before wait_iff_congested(), the page allocator would incur an
unconditional timeout and allow kswapd to elevate zone->pages_scanned to
a level that the oom killer would be called the next time it loops.

The fix is to only attempt to drain pcp pages if there is actually a
quantity to be drained.  The unconditional clearing of
zone->pages_scanned in free_pcppages_bulk() need not be changed since
other callers already ensure that draining will occur.  This patch
ensures that free_pcppages_bulk() will actually free memory before
calling into it from drain_all_pages() so zone->pages_scanned is only
cleared if appropriate.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Before 0e093d99 ("writeback: do not sleep on the congestion queue if
there are no congested BDIs or if significant congestion is not being
encountered in the current zone"), preferred_zone was only used for NUMA
statistics, to determine the zoneidx from which to allocate from given
the type requested, and whether to utilize memory compaction.

wait_iff_congested(), though, uses preferred_zone to determine if the
congestion wait should be deferred because its dirty pages are backed by
a congested bdi.  This incorrectly defers the timeout and busy loops in
the page allocator with various cond_resched() calls if preferred_zone
is not allowed in the current context, usually consuming 100% of a cpu.

This patch ensures preferred_zone is an allowed zone in the fastpath
depending on whether current is constrained by its cpuset or nodes in
its mempolicy (when the nodemask passed is non-NULL).  This is correct
since the fastpath allocation always passes ALLOC_CPUSET when trying to
allocate memory.  In the slowpath, this patch resets preferred_zone to
the first zone of the allowed type when the allocation is not
constrained by current's cpuset, i.e.  it does not pass ALLOC_CPUSET.

This patch also ensures preferred_zone is from the set of allowed nodes
when called from within direct reclaim since allocations are always
constrained by cpusets in this context (it is blockable).

Both of these uses of cpuset_current_mems_allowed are protected by
get_mems_allowed().
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mips (and sparc32):

  In file included from arch/mips/include/asm/tlb.h:21,
                   from mm/pgtable-generic.c:9:
  include/asm-generic/tlb.h: In function `tlb_flush_mmu':
  include/asm-generic/tlb.h:76: error: implicit declaration of function `release_pages'
  include/asm-generic/tlb.h: In function `tlb_remove_page':
  include/asm-generic/tlb.h:105: error: implicit declaration of function `page_cache_release'

free_pages_and_swap_cache() and free_page_and_swap_cache() are macros
which call release_pages() and page_cache_release().  The obvious fix is
to include pagemap.h in swap.h, where those macros are defined.  But that
breaks sparc for weird reasons.

So fix it within mm/pgtable-generic.c instead.
Reported-by: NYoichi Yuasa <yuasa@linux-mips.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Cc: Sergei Shtylyov <sshtylyov@mvista.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The placement of the read-side barrier is confused: the writer first
sets pc->mem_cgroup, then PCG_USED.  The read-side barrier has to be
between testing PCG_USED and reading pc->mem_cgroup.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Contrary to what the comment says, truncate_setsize() should be called
*before* filesystem truncated blocks.
Signed-off-by: NJan Kara <jack@suse.cz>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now, when THP is enabled, memcg's rmdir() function is broken because
move_account() for THP page is not supported.

This will cause account leak or -EBUSY issue at rmdir().
This patch fixes the issue by supporting move_account() THP pages.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memory cgroup's LRU stat should take care of size of pages because
Transparent Hugepage inserts hugepage into LRU.  If this value is the
number wrong, memory reclaim will not work well.

Note: only head page of THP's huge page is linked into LRU.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Now, under THP:

at charge:
  - PageCgroupUsed bit is set to all page_cgroup on a hugepage.
    ....set to 512 pages.
at uncharge
  - PageCgroupUsed bit is unset on the head page.

So, some pages will remain with "Used" bit.

This patch fixes that Used bit is set only to the head page.
Used bits for tail pages will be set at splitting if necessary.

This patch adds this lock order:
   compound_lock() -> page_cgroup_move_lock().

[akpm@linux-foundation.org: fix warning]
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mem_cgroup_charge_statisics() was designed for charging a page but now, we
have transparent hugepage.  To fix problems (in following patch) it's
required to change the function to get the number of pages as its
arguments.

The new function gets following as argument.
  - type of page rather than 'pc'
  - size of page which is accounted.
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Up until 3e7d3449 ("mm: vmscan: reclaim order-0 and use compaction instead
of lumpy reclaim"), compaction skipped calculating the fragmentation index
of a zone when compaction was explicitely requested through the procfs
knob.

However, when compaction_suitable was introduced, it did not come with an
extra check for order == -1, set on explicit compaction requests, and
passed this order on to the fragmentation index calculation, where it
overshifts the number of requested pages, leading to a division by zero.

This patch makes sure that order == -1 is recognized as the flag it is
rather than passing it along as valid order parameter.

[akpm@linux-foundation.org: add comment, per Mel]
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NMel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NJesper Juhl <jj@chaosbits.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memblock_is_region_memory() uses reserved memblocks to search for the
given region, while it should use the memory memblocks.

I encountered the problem with OMAP's framebuffer ram allocation.
Normally the ram is allocated dynamically, and this function is not
called.  However, if we want to pass the framebuffer from the bootloader
to the kernel (to retain the boot image), this function is used to check
the validity of the kernel parameters for the framebuffer ram area.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@nokia.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Two users reported THP-related crashes on 32-bit x86 machines.  Their oops
reports indicated an invalid pte, and subsequent code inspection showed
that the highpte is actually used after unmap.

The fix is to unmap the pte only after all operations against it are
finished.
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reported-by: NIlya Dryomov <idryomov@gmail.com>
Reported-by: Nwerner <w.landgraf@ru.ru>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Tested-by: NIlya Dryomov <idryomov@gmail.com>
Tested-by: Steven Rostedt <rostedt@goodmis.org
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>