linux.git/mm/memcontrol.c, branch v2.6.38

memcg: fix event counting breakage from recent THP update

2011-02-03T00:03:19+00:00

Changes in e401f1761 ("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: KAMEZAWA Hiroyuki 
Reviewed-by: Johannes Weiner 
Cc: Daisuke Nishimura 
Cc: Balbir Singh 
Cc: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: never OOM when charging huge pages

2011-02-03T00:03:19+00:00

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: Johannes Weiner 
Acked-by: KAMEZAWA Hiroyuki 
Reviewed-by: Minchan Kim 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: prevent endless loop when charging huge pages to near-limit group

2011-02-03T00:03:19+00:00

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: Johannes Weiner 
Acked-by: KAMEZAWA Hiroyuki 
Reviewed-by: Minchan Kim 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: prevent endless loop when charging huge pages

2011-02-03T00:03:19+00:00

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: Johannes Weiner 
Acked-by: KAMEZAWA Hiroyuki 
Reviewed-by: Minchan Kim 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memsw: deprecate noswapaccount kernel parameter and schedule it for removal

2011-02-03T00:03:18+00:00

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: Michal Hocko 
Requested-by: KAMEZAWA Hiroyuki 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memsw: handle swapaccount kernel parameter correctly

2011-02-03T00:03:18+00:00

__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: Michal Hocko 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Daisuke Nishimura 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix race at move_parent around compound_order()

2011-01-26T00:50:04+00:00

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: KAMEZAWA Hiroyuki 
Reviewed-by: Johannes Weiner 
Acked-by: Daisuke Nishimura 
Cc: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: bugfix check mem_cgroup_disabled() at split fixup

2011-01-26T00:50:03+00:00

mem_cgroup_disabled() should be checked at splitting.  If disabled, no
heavy work is necesary.

Signed-off-by: KAMEZAWA Hiroyuki 
Acked-by: Daisuke Nishimura 
Reviewed-by: Johannes Weiner 
Cc: Balbir Singh 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix account leak at failure of memsw acconting

2011-01-26T00:50:03+00:00

Commit 4b53433468 ("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: KAMEZAWA Hiroyuki 
Reviewed-by: Johannes Weiner 
Acked-by: Daisuke Nishimura 
Cc: Balbir Singh 
Cc: 	[2.6.36+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm/memcontrol.c: fix uninitialized variable use in mem_cgroup_move_parent()

2011-01-26T00:50:01+00:00

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: Jesper Juhl 
Cc: Balbir Singh 
Cc: Daisuke Nishimura 
Cc: KAMEZAWA Hiroyuki 
Cc: Pavel Emelianov 
Cc: "Kirill A. Shutemov" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds