linux.git/mm/memcontrol.c, branch v2.6.31

cgroup avoid permanent sleep at rmdir

2009-07-30T02:10:35+00:00

After commit ec64f51545fffbc4cb968f0cea56341a4b07e85a ("cgroup: fix
frequent -EBUSY at rmdir"), cgroup's rmdir (especially against memcg)
doesn't return -EBUSY by temporary ref counts.  That commit expects all
refs after pre_destroy() is temporary but...it wasn't.  Then, rmdir can
wait permanently.  This patch tries to fix that and change followings.

 - set CGRP_WAIT_ON_RMDIR flag before pre_destroy().
 - clear CGRP_WAIT_ON_RMDIR flag when the subsys finds racy case.
   if there are sleeping ones, wakes them up.
 - rmdir() sleeps only when CGRP_WAIT_ON_RMDIR flag is set.

Tested-by: Daisuke Nishimura 
Reported-by: Daisuke Nishimura 
Reviewed-by: Paul Menage 
Acked-by: Balbir Sigh 
Signed-off-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Fix congestion_wait() sync/async vs read/write confusion

2009-07-10T18:31:53+00:00

Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke
the bdi congestion wait queue logic, causing us to wait on congestion
for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead.

Signed-off-by: Jens Axboe

memcg: fix lru rotation in isolate_pages

2009-06-18T20:03:48+00:00

Try to fix memcg's lru rotation sanity: make memcg use the same logic as
the global LRU does.

Now, at __isolate_lru_page() retruns -EBUSY, the page is rotated to the
tail of LRU in global LRU's isolate LRU pages.  But in memcg, it's not
handled.  This makes memcg do the same behavior as global LRU and rotate
LRU in the page is busy.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: KOSAKI Motohiro 
Acked-by: Daisuke Nishimura 
Cc: Balbir Singh 
Cc: Mel Gorman 
Cc: Minchan Kim 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix behavior under memory.limit equals to memsw.limit

2009-06-18T20:03:48+00:00

A user can set memcg.limit_in_bytes == memcg.memsw.limit_in_bytes when the
user just want to limit the total size of applications, in other words,
not very interested in memory usage itself.  In this case, swap-out will
be done only by global-LRU.

But, under current implementation, memory.limit_in_bytes is checked at
first and try_to_free_page() may do swap-out.  But, that swap-out is
useless for memsw.limit_in_bytes and the thread may hit limit again.

This patch tries to fix the current behavior at memory.limit ==
memsw.limit case.  And documentation is updated to explain the behavior of
this special case.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Daisuke Nishimura 
Cc: Balbir Singh 
Cc: Li Zefan 
Cc: Dhaval Giani 
Cc: YAMAMOTO Takashi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix swap accounting

2009-06-18T20:03:47+00:00

This patch fixes mis-accounting of swap usage in memcg.

In the current implementation, memcg's swap account is uncharged only when
swap is completely freed.  But there are several cases where swap cannot
be freed cleanly.  For handling that, this patch changes that memcg
uncharges swap account when swap has no references other than cache.

By this, memcg's swap entry accounting can be fully synchronous with the
application's behavior.

This patch also changes memcg's hooks for swap-out.

Signed-off-by: KAMEZAWA Hiroyuki 
Cc: Daisuke Nishimura 
Acked-by: Balbir Singh 
Cc: Hugh Dickins 
Cc: Johannes Weiner 
Cc: Li Zefan 
Cc: Dhaval Giani 
Cc: YAMAMOTO Takashi 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: remove some redundant checks

2009-06-18T20:03:47+00:00

We don't need to check do_swap_account in the case that the function which
checks do_swap_account will never get called if do_swap_account == 0.

Signed-off-by: Li Zefan 
Cc: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: add file-based RSS accounting

2009-06-18T20:03:47+00:00

Add file RSS tracking per memory cgroup

We currently don't track file RSS, the RSS we report is actually anon RSS.
 All the file mapped pages, come in through the page cache and get
accounted there.  This patch adds support for accounting file RSS pages.
It should

1. Help improve the metrics reported by the memory resource controller
2. Will form the basis for a future shared memory accounting heuristic
   that has been proposed by Kamezawa.

Unfortunately, we cannot rename the existing "rss" keyword used in
memory.stat to "anon_rss".  We however, add "mapped_file" data and hope to
educate the end user through documentation.

[hugh.dickins@tiscali.co.uk: fix mem_cgroup_update_mapped_file_stat oops]
Signed-off-by: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Li Zefan 
Cc: Paul Menage 
Cc: Dhaval Giani 
Cc: Daisuke Nishimura 
Cc: YAMAMOTO Takashi 
Cc: KOSAKI Motohiro 
Cc: David Rientjes 
Signed-off-by: Hugh Dickins 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vmscan: evict use-once pages first

2009-06-17T02:47:38+00:00

When the file LRU lists are dominated by streaming IO pages, evict those
pages first, before considering evicting other pages.

This should be safe from deadlocks or performance problems
because only three things can happen to an inactive file page:

1) referenced twice and promoted to the active list
2) evicted by the pageout code
3) under IO, after which it will get evicted or promoted

The pages freed in this way can either be reused for streaming IO, or
allocated for something else.  If the pages are used for streaming IO,
this pageout pattern continues.  Otherwise, we will fall back to the
normal pageout pattern.

Signed-off-by: Rik van Riel 
Reported-by: Elladan 
Cc: KOSAKI Motohiro 
Cc: Peter Zijlstra 
Cc: Lee Schermerhorn 
Acked-by: Johannes Weiner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix build warning and avoid checking for mem != null again and again

2009-05-29T15:40:03+00:00

Fix build warning, "mem_cgroup_is_obsolete defined but not used" when
CONFIG_DEBUG_VM is not set.  Also avoid checking for !mem again and again.

Signed-off-by: Nikanth Karthikesan 
Acked-by: Pekka Enberg 
Acked-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memcg: fix deadlock between lock_page_cgroup and mapping tree_lock

2009-05-29T15:40:02+00:00

mapping->tree_lock can be acquired from interrupt context.  Then,
following dead lock can occur.

Assume "A" as a page.

 CPU0:
       lock_page_cgroup(A)
		interrupted
			-> take mapping->tree_lock.
 CPU1:
       take mapping->tree_lock
		-> lock_page_cgroup(A)

This patch tries to fix above deadlock by moving memcg's hook to out of
mapping->tree_lock.  charge/uncharge of pagecache/swapcache is protected
by page lock, not tree_lock.

After this patch, lock_page_cgroup() is not called under mapping->tree_lock.

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