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308900 Commits (75b00af77ed5b5a3d55549f9e0c33f3969b9330c)

Author SHA1 Message Date
Hugh Dickins 75b00af77e mm: trivial cleanups in vmscan.c
Utter trivia in mm/vmscan.c, mostly just reducing the linecount slightly;
most exciting change being get_scan_count() calling vmscan_swappiness()
once instead of twice.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:28 -07:00
Hugh Dickins 4d7dcca213 mm/memcg: get_lru_size not get_lruvec_size
Konstantin just introduced mem_cgroup_get_lruvec_size() and
get_lruvec_size(), I'm about to add mem_cgroup_update_lru_size(): but
we're dealing with the same thing, lru_size[lru].  We ought to agree on
the naming, and I do think lru_size is the more correct: so rename his
ones to get_lru_size().

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:28 -07:00
Johannes Weiner af7c4b0ec2 mm: memcg: print statistics from live counters
Directly print statistics and event counters instead of going through an
intermediate accumulation stage into a separate array, which used to
require defining statistic items in more than one place.

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:28 -07:00
Johannes Weiner fad02c2de0 mm: memcg: group swapped-out statistics counter logically
The counter of currently swapped out pages in a memcg (hierarchy) is
sitting amidst ever-increasing event counters.  Move this item to the
other counters that reflect current state rather than history.

This technically breaks the kernel ABI, but hopefully nobody relies on the
order of items in memory.stat.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:28 -07:00
Johannes Weiner 13114716c7 mm: memcg: keep ratelimit counter separate from event counters
All events except the ratelimit counter are statistics exported to
userspace.  Keep this internal value out of the event count array.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Johannes Weiner 78ccf5b5ab mm: memcg: print statistics directly to seq_file
Being able to use seq_printf() allows being smarter about statistics
name strings, which are currently listed twice, with the only difference
being a "total_" prefix on the hierarchical version.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Johannes Weiner fada52ca0e mm: memcg: convert numa stat to read_seq_string interface
Instead of using the raw seq_file file interface, switch over to the
read_seq_string cftype callback and let cgroup core code set up the
seq_file.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Johannes Weiner 6104621de4 mm: memcg: remove obsolete statistics array boundary enum item
MEM_CGROUP_STAT_DATA is a leftover from when item counters were living in
the same array as ever-increasing event counters.  It's no longer needed,
use MEM_CGROUP_STAT_NSTATS to iterate over the stat array.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Glauber Costa 04eac7ffde rescounter: remove __must_check from res_counter_charge_nofail()
Since we will succeed with the allocation no matter what, there isn't a
need to use __must_check with it.  It can very well be optional.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ying Han <yinghan@google.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
KAMEZAWA Hiroyuki 2f3479b147 memcg: don't uncharge in mem_cgroup_move_account()
Now, all callers pass 'false' for 'bool uncharge' so remove this argument.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
KAMEZAWA Hiroyuki cc926f7842 memcg: move charges to root cgroup if use_hierarchy=0
Presently, at removal of cgroup, ->pre_destroy() is called and moves
charges to the parent cgroup.  A major reason for returning -EBUSY from
->pre_destroy() is that the 'moving' hits the parent's resource
limitation.  It happens only when use_hierarchy=0.

Considering use_hierarchy=0, all cgroups should be flat.  So, no one
cannot justify moving charges to parent...parent and children are in flat
configuration, not hierarchical.

This patch modifes the code to move charges to the root cgroup at
rmdir/force_empty if use_hierarchy==0.  This will much simplify rmdir()
and reduce error in ->pre_destroy.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
KAMEZAWA Hiroyuki d01dd17f10 memcg: use res_counter_uncharge_until() in move_parent()
By using res_counter_uncharge_until(), we can avoid race and unnecessary
charging.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Frederic Weisbecker 2bb2ba9d51 rescounters: add res_counter_uncharge_until()
When killing a res_counter which is a child of other counter, we need to
do

	res_counter_uncharge(child, xxx)
	res_counter_charge(parent, xxx)

This is not atomic and wastes CPU.  This patch adds
res_counter_uncharge_until().  This function's uncharge propagates to
ancestors until specified res_counter.

	res_counter_uncharge_until(child, parent, xxx)

Now the operation is atomic and efficient.

Signed-off-by: Frederic Weisbecker <fweisbec@redhat.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Konstantin Khlebnikov f9be23d6da mm/vmscan: kill struct mem_cgroup_zone
Kill struct mem_cgroup_zone and rename shrink_mem_cgroup_zone() to
shrink_lruvec(), it always shrinks one lruvec which it takes as an
argument.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Konstantin Khlebnikov 90bdcfafdc mm/vmscan: push lruvec pointer into should_continue_reclaim()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:27 -07:00
Konstantin Khlebnikov 90126375d8 mm/vmscan: push lruvec pointer into get_scan_count()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 1a93be0e7a mm/vmscan: push lruvec pointer into shrink_list()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov c56d5c7dfe mm/vmscan: push lruvec pointer into inactive_list_is_low()
Switch mem_cgroup_inactive_anon_is_low() to lruvec pointers,
mem_cgroup_get_lruvec_size() is more effective than
mem_cgroup_zone_nr_lru_pages()

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 074291fea8 mm/vmscan: replace zone_nr_lru_pages() with get_lruvec_size()
If memory cgroup is enabled we always use lruvecs which are embedded into
struct mem_cgroup_per_zone, so we can reach lru_size counters via
container_of().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 27ac81d85e mm/vmscan: push lruvec pointer into putback_inactive_pages()
As zone_reclaim_stat is now located in the lruvec, we can reach it
directly.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 95d918fc00 mm/vmscan: remove update_isolated_counts()
update_isolated_counts() is no longer required, because lumpy-reclaim was
removed.  Insanity is over, now there is only one kind of inactive page.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 6a18adb35c mm/vmscan: push zone pointer into shrink_page_list()
It doesn't need a pointer to the cgroup - pointer to the zone is enough.
This patch also kills the "mz" argument of page_check_references() - it is
unused after "mm: memcg: count pte references from every member of the
reclaimed hierarch"

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 5dc35979e4 mm/vmscan: push lruvec pointer into isolate_lru_pages()
Move the mem_cgroup_zone_lruvec() call from isolate_lru_pages() into
shrink_[in]active_list().  Further patches push it to shrink_zone() step
by step.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 7f5e86c2cc mm: add link from struct lruvec to struct zone
This is the first stage of struct mem_cgroup_zone removal.  Further
patches replace struct mem_cgroup_zone with a pointer to struct lruvec.

If CONFIG_CGROUP_MEM_RES_CTLR=n lruvec_zone() is just container_of().

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 9e3b2f8cd3 mm/vmscan: store "priority" in struct scan_control
In memory reclaim some function have too many arguments - "priority" is
one of them.  It can be stored in struct scan_control - we construct them
on the same level.  Instead of an open coded loop we set the initial
sc.priority, and do_try_to_free_pages() decreases it down to zero.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Konstantin Khlebnikov 3d58ab5c97 mm/memcg: use vm_swappiness from target memory cgroup
Use vm_swappiness from memory cgroup which is triggered this memory
reclaim.  This is more reasonable and allows to kill one argument.

[akpm@linux-foundation.org: fix build (patch skew)]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:26 -07:00
Sha Zhengju 748dad36d6 memcg: make threshold index in the right position
Index current_threshold may point to threshold that just equal to usage
after last call of __mem_cgroup_threshold.  But after registering a new
event, it will change (pointing to threshold just below usage).  So make
it consistent here.

For example:
now:
	threshold array:  3  [5]  7  9   (usage = 6, [index] = 5)

next turn (after calling __mem_cgroup_threshold):
	threshold array:  3   5  [7]  9   (usage = 7, [index] = 7)

after registering a new event (threshold = 10):
	threshold array:  3  [5]  7  9  10 (usage = 7, [index] = 5)

Signed-off-by: Sha Zhengju <handai.szj@taobao.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Kirill A. Shutemov a0db00fcf5 memcg: remove redundant parentheses
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Kirill A. Shutemov 3a7951b4cf memcg: mark stat field of mem_cgroup struct as __percpu
It fixes a lot of sparse warnings.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Kirill A. Shutemov 92ba39a7ac memcg: remove unused variable
mm/memcontrol.c: In function `mc_handle_file_pte':
mm/memcontrol.c:5206:16: warning: variable `inode' set but not used [-Wunused-but-set-variable]

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Kirill A. Shutemov 6bbda35ce1 memcg: mark more functions/variables as static
Based on sparse output.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Konstantin Khlebnikov bbf808ed7d mm/memcg: kill mem_cgroup_lru_del()
This patch kills mem_cgroup_lru_del(), we can use
mem_cgroup_lru_del_list() instead.  On 0-order isolation we already have
right lru list id.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Konstantin Khlebnikov f3fd4a6192 mm: remove lru type checks from __isolate_lru_page()
After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can
completely remove anon/file and active/inactive lru type filters from
__isolate_lru_page(), because isolation for 0-order reclaim always
isolates pages from right lru list.  And pages-isolation for lumpy
shrink_inactive_list() or memory-compaction anyway allowed to isolate
pages from all evictable lru lists.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Konstantin Khlebnikov 014483bccc mm: mark mm-inline functions as __always_inline
GCC sometimes ignores "inline" directives even for small and simple functions.
This supposed to be fixed in gcc 4.7, but it was released only yesterday.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Konstantin Khlebnikov 3cb9945179 mm: push lru index into shrink_[in]active_list()
Let's toss lru index through call stack to isolate_lru_pages(), this is
better than its reconstructing from individual bits.

[akpm@linux-foundation.org: fix kerneldoc, per Minchan]
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Hugh Dickins 89abfab133 mm/memcg: move reclaim_stat into lruvec
With mem_cgroup_disabled() now explicit, it becomes clear that the
zone_reclaim_stat structure actually belongs in lruvec, per-zone when
memcg is disabled but per-memcg per-zone when it's enabled.

We can delete mem_cgroup_get_reclaim_stat(), and change
update_page_reclaim_stat() to update just the one set of stats, the one
which get_scan_count() will actually use.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Hugh Dickins c3c787e8c3 mm/memcg: scanning_global_lru means mem_cgroup_disabled
Although one has to admire the skill with which it has been concealed,
scanning_global_lru(mz) is actually just an interesting way to test
mem_cgroup_disabled().  Too many developer hours have been wasted on
confusing it with global_reclaim(): just use mem_cgroup_disabled().

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Glauber Costa <glommer@parallels.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:25 -07:00
Hugh Dickins 86493009d3 memcg swap: use mem_cgroup_uncharge_swap()
That stuff __mem_cgroup_commit_charge_swapin() does with a swap entry, it
has a name and even a declaration: just use mem_cgroup_uncharge_swap().

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Hugh Dickins e91cbb4253 memcg swap: mem_cgroup_move_swap_account never needs fixup
The need_fixup arg to mem_cgroup_move_swap_account() is always false,
so just remove it.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
KAMEZAWA Hiroyuki 4b91355e9d memcg: fix/change behavior of shared anon at moving task
This patch changes memcg's behavior at task_move().

At task_move(), the kernel scans a task's page table and move the changes
for mapped pages from source cgroup to target cgroup.  There has been a
bug at handling shared anonymous pages for a long time.

Before patch:
  - The spec says 'shared anonymous pages are not moved.'
  - The implementation was 'shared anonymoys pages may be moved'.
    If page_mapcount <=2, shared anonymous pages's charge were moved.

After patch:
  - The spec says 'all anonymous pages are moved'.
  - The implementation is 'all anonymous pages are moved'.

Considering usage of memcg, this will not affect user's experience.
'shared anonymous' pages only exists between a tree of processes which
don't do exec().  Moving one of process without exec() seems not sane.
For example, libcgroup will not be affected by this change.  (Anyway, no
one noticed the implementation for a long time...)

Below is a discussion log:

 - current spec/implementation are complex
 - Now, shared file caches are moved
 - It adds unclear check as page_mapcount(). To do correct check,
   we should check swap users, etc.
 - No one notice this implementation behavior. So, no one get benefit
   from the design.
 - In general, once task is moved to a cgroup for running, it will not
   be moved....
 - Finally, we have control knob as memory.move_charge_at_immigrate.

Here is a patch to allow moving shared pages, completely. This makes
memcg simpler and fix current broken code.

Suggested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Glauber Costa <glommer@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Gavin Shan 181eb39425 mm/memblock: fix memory leak on extending regions
The overall memblock has been organized into the memory regions and
reserved regions.  Initially, the memory regions and reserved regions are
stored in the predetermined arrays of "struct memblock _region".  It's
possible for the arrays to be enlarged when we have newly added regions,
but no free space left there.  The policy here is to create double-sized
array either by slab allocator or memblock allocator.  Unfortunately, we
didn't free the old array, which might be allocated through slab allocator
before.  That would cause memory leak.

The patch introduces 2 variables to trace where (slab or memblock) the
memory and reserved regions come from.  The memory for the memory or
reserved regions will be deallocated by kfree() if that was allocated by
slab allocator.  Thus to fix the memory leak issue.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Gavin Shan 4e2f07750d mm/memblock: cleanup on duplicate VA/PA conversion
The overall memblock has been organized into the memory regions and
reserved regions.  Initially, the memory regions and reserved regions are
stored in the predetermined arrays of "struct memblock _region".  It's
possible for the arrays to be enlarged when we have newly added regions
for them, but no enough space there.  Under the situation, We will created
double-sized array to meet the requirement.  However, the original
implementation converted the VA (Virtual Address) of the newly allocated
array of regions to PA (Physical Address), then translate back when we
allocates the new array from slab.  That's actually unnecessary.

The patch removes the duplicate VA/PA conversion.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Pravin B Shelar 5bf5f03c27 mm: fix slab->page flags corruption
Transparent huge pages can change page->flags (PG_compound_lock) without
taking Slab lock.  Since THP can not break slab pages we can safely access
compound page without taking compound lock.

Specifically this patch fixes a race between compound_unlock() and slab
functions which perform page-flags updates.  This can occur when
get_page()/put_page() is called on a page from slab.

[akpm@linux-foundation.org: tweak comment text, fix comment layout, fix label indenting]
Reported-by: Amey Bhide <abhide@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
KyongHo dbda591d92 mm: fix faulty initialization in vmalloc_init()
The transfer of ->flags causes some of the static mapping virtual
addresses to be prematurely freed (before the mapping is removed) because
VM_LAZY_FREE gets "set" if tmp->flags has VM_IOREMAP set.  This might
cause subsequent vmalloc/ioremap calls to fail because it might allocate
one of the freed virtual address ranges that aren't unmapped.

va->flags has different types of flags from tmp->flags.  If a region with
VM_IOREMAP set is registered with vm_area_add_early(), it will be removed
by __purge_vmap_area_lazy().

Fix vmalloc_init() to correctly initialize vmap_area for the given
vm_struct.

Also initialise va->vm.  If it is not set, find_vm_area() for the early
vm regions will always fail.

Signed-off-by: KyongHo Cho <pullip.cho@samsung.com>
Cc: "Olav Haugan" <ohaugan@codeaurora.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Andrea Arcangeli 26c191788f mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition
When holding the mmap_sem for reading, pmd_offset_map_lock should only
run on a pmd_t that has been read atomically from the pmdp pointer,
otherwise we may read only half of it leading to this crash.

PID: 11679  TASK: f06e8000  CPU: 3   COMMAND: "do_race_2_panic"
 #0 [f06a9dd8] crash_kexec at c049b5ec
 #1 [f06a9e2c] oops_end at c083d1c2
 #2 [f06a9e40] no_context at c0433ded
 #3 [f06a9e64] bad_area_nosemaphore at c043401a
 #4 [f06a9e6c] __do_page_fault at c0434493
 #5 [f06a9eec] do_page_fault at c083eb45
 #6 [f06a9f04] error_code (via page_fault) at c083c5d5
    EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP:
    00000000
    DS:  007b     ESI: 9e201000 ES:  007b     EDI: 01fb4700 GS:  00e0
    CS:  0060     EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246
 #7 [f06a9f38] _spin_lock at c083bc14
 #8 [f06a9f44] sys_mincore at c0507b7d
 #9 [f06a9fb0] system_call at c083becd
                         start           len
    EAX: ffffffda  EBX: 9e200000  ECX: 00001000  EDX: 6228537f
    DS:  007b      ESI: 00000000  ES:  007b      EDI: 003d0f00
    SS:  007b      ESP: 62285354  EBP: 62285388  GS:  0033
    CS:  0073      EIP: 00291416  ERR: 000000da  EFLAGS: 00000286

This should be a longstanding bug affecting x86 32bit PAE without THP.
Only archs with 64bit large pmd_t and 32bit unsigned long should be
affected.

With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad()
would partly hide the bug when the pmd transition from none to stable,
by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is
enabled a new set of problem arises by the fact could then transition
freely in any of the none, pmd_trans_huge or pmd_trans_stable states.
So making the barrier in pmd_none_or_trans_huge_or_clear_bad()
unconditional isn't good idea and it would be a flakey solution.

This should be fully fixed by introducing a pmd_read_atomic that reads
the pmd in order with THP disabled, or by reading the pmd atomically
with cmpxchg8b with THP enabled.

Luckily this new race condition only triggers in the places that must
already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix
is localized there but this bug is not related to THP.

NOTE: this can trigger on x86 32bit systems with PAE enabled with more
than 4G of ram, otherwise the high part of the pmd will never risk to be
truncated because it would be zero at all times, in turn so hiding the
SMP race.

This bug was discovered and fully debugged by Ulrich, quote:

----
[..]
pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and
eax.

    496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t
    *pmd)
    497 {
    498         /* depend on compiler for an atomic pmd read */
    499         pmd_t pmdval = *pmd;

                                // edi = pmd pointer
0xc0507a74 <sys_mincore+548>:   mov    0x8(%esp),%edi
...
                                // edx = PTE page table high address
0xc0507a84 <sys_mincore+564>:   mov    0x4(%edi),%edx
...
                                // eax = PTE page table low address
0xc0507a8e <sys_mincore+574>:   mov    (%edi),%eax

[..]

Please note that the PMD is not read atomically. These are two "mov"
instructions where the high order bits of the PMD entry are fetched
first. Hence, the above machine code is prone to the following race.

-  The PMD entry {high|low} is 0x0000000000000000.
   The "mov" at 0xc0507a84 loads 0x00000000 into edx.

-  A page fault (on another CPU) sneaks in between the two "mov"
   instructions and instantiates the PMD.

-  The PMD entry {high|low} is now 0x00000003fda38067.
   The "mov" at 0xc0507a8e loads 0xfda38067 into eax.
----

Reported-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Larry Woodman <lwoodman@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
David Rientjes a7f638f999 mm, oom: normalize oom scores to oom_score_adj scale only for userspace
The oom_score_adj scale ranges from -1000 to 1000 and represents the
proportion of memory available to the process at allocation time.  This
means an oom_score_adj value of 300, for example, will bias a process as
though it was using an extra 30.0% of available memory and a value of
-350 will discount 35.0% of available memory from its usage.

The oom killer badness heuristic also uses this scale to report the oom
score for each eligible process in determining the "best" process to
kill.  Thus, it can only differentiate each process's memory usage by
0.1% of system RAM.

On large systems, this can end up being a large amount of memory: 256MB
on 256GB systems, for example.

This can be fixed by having the badness heuristic to use the actual
memory usage in scoring threads and then normalizing it to the
oom_score_adj scale for userspace.  This results in better comparison
between eligible threads for kill and no change from the userspace
perspective.

Suggested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Tested-by: Dave Jones <davej@redhat.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Satoru Moriya fe35004fbf mm: avoid swapping out with swappiness==0
Sometimes we'd like to avoid swapping out anonymous memory.  In
particular, avoid swapping out pages of important process or process
groups while there is a reasonable amount of pagecache on RAM so that we
can satisfy our customers' requirements.

OTOH, we can control how aggressive the kernel will swap memory pages with
/proc/sys/vm/swappiness for global and
/sys/fs/cgroup/memory/memory.swappiness for each memcg.

But with current reclaim implementation, the kernel may swap out even if
we set swappiness=0 and there is pagecache in RAM.

This patch changes the behavior with swappiness==0.  If we set
swappiness==0, the kernel does not swap out completely (for global reclaim
until the amount of free pages and filebacked pages in a zone has been
reduced to something very very small (nr_free + nr_filebacked < high
watermark)).

Signed-off-by: Satoru Moriya <satoru.moriya@hds.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Dave Hansen c50ac05081 hugetlb: fix resv_map leak in error path
When called for anonymous (non-shared) mappings, hugetlb_reserve_pages()
does a resv_map_alloc().  It depends on code in hugetlbfs's
vm_ops->close() to release that allocation.

However, in the mmap() failure path, we do a plain unmap_region() without
the remove_vma() which actually calls vm_ops->close().

This is a decent fix.  This leak could get reintroduced if new code (say,
after hugetlb_reserve_pages() in hugetlbfs_file_mmap()) decides to return
an error.  But, I think it would have to unroll the reservation anyway.

Christoph's test case:

	http://marc.info/?l=linux-mm&m=133728900729735

This patch applies to 3.4 and later.  A version for earlier kernels is at
https://lkml.org/lkml/2012/5/22/418.

Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reported-by: Christoph Lameter <cl@linux.com>
Tested-by: Christoph Lameter <cl@linux.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: <stable@vger.kernel.org>	[2.6.32+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Gavin Shan 5c2b8a162b mm/bootmem.c: cleanup on addition to bootmem data list
The objects of "struct bootmem_data_t" are linked together to form
double-linked list sequentially based on its minimal page frame number.

The current implementation implicitly supports the following cases,
which means the inserting point for current bootmem data depends on how
"list_for_each" works.  That makes the code a little hard to read.
Besides, "list_for_each" and "list_entry" can be replaced with
"list_for_each_entry".

        - The linked list is empty.
        - There has no entry in the linked list, whose minimal page
          frame number is bigger than current one.

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:24 -07:00
Michal Hocko e48982734e mm: consider all swapped back pages in used-once logic
Commit 6457474624 ("vmscan: detect mapped file pages used only once")
made mapped pages have another round in inactive list because they might
be just short lived and so we could consider them again next time.  This
heuristic helps to reduce pressure on the active list with a streaming
IO worklods.

This patch fixes a regression introduced by this commit for heavy shmem
based workloads because unlike Anon pages, which are excluded from this
heuristic because they are usually long lived, shmem pages are handled
as a regular page cache.

This doesn't work quite well, unfortunately, if the workload is mostly
backed by shmem (in memory database sitting on 80% of memory) with a
streaming IO in the background (backup - up to 20% of memory).  Anon
inactive list is full of (dirty) shmem pages when watermarks are hit.
Shmem pages are kept in the inactive list (they are referenced) in the
first round and it is hard to reclaim anything else so we reach lower
scanning priorities very quickly which leads to an excessive swap out.

Let's fix this by excluding all swap backed pages (they tend to be long
lived wrt.  the regular page cache anyway) from used-once heuristic and
rather activate them if they are referenced.

The customer's workload is shmem backed database (80% of RAM) and they
are measuring transactions/s with an IO in the background (20%).
Transactions touch more or less random rows in the table.  The
transaction rate fell by a factor of 3 (in the worst case) because of
commit 64574746.  This patch restores the previous numbers.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>	[2.6.34+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-29 16:22:23 -07:00