summaryrefslogtreecommitdiff
path: root/mm
diff options
context:
space:
mode:
authorKirill A. Shutemov <kirill@shutemov.name>2010-03-10 15:22:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2010-03-12 15:52:37 -0800
commit378ce724bc2a0ef1243e11c09d58a70bb6be007a (patch)
tree6a0a239547179842a55f9ffc9501cc9d2b0f5499 /mm
parent104f39284e830f425085886ef72c49aee6631575 (diff)
downloadconfigs-378ce724bc2a0ef1243e11c09d58a70bb6be007a.tar.gz
memcg: rework usage of stats by soft limit
Instead of incrementing counter on each page in/out and comparing it with constant, we set counter to constant, decrement counter on each page in/out and compare it with zero. We want to make comparing as fast as possible. On many RISC systems (probably not only RISC) comparing with zero is more effective than comparing with a constant, since not every constant can be immediate operand for compare instruction. Also, I've renamed MEM_CGROUP_STAT_EVENTS to MEM_CGROUP_STAT_SOFTLIMIT, since really it's not a generic counter. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 5f8f93d83ed..5a41d93c707 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -71,8 +71,9 @@ enum mem_cgroup_stat_index {
MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */
MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */
- MEM_CGROUP_STAT_EVENTS, /* sum of pagein + pageout for internal use */
MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+ MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out.
+ used by soft limit implementation */
MEM_CGROUP_STAT_NSTATS,
};
@@ -86,10 +87,10 @@ struct mem_cgroup_stat {
};
static inline void
-__mem_cgroup_stat_reset_safe(struct mem_cgroup_stat_cpu *stat,
- enum mem_cgroup_stat_index idx)
+__mem_cgroup_stat_set_safe(struct mem_cgroup_stat_cpu *stat,
+ enum mem_cgroup_stat_index idx, s64 val)
{
- stat->count[idx] = 0;
+ stat->count[idx] = val;
}
static inline s64
@@ -411,9 +412,10 @@ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
cpu = get_cpu();
cpustat = &mem->stat.cpustat[cpu];
- val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_EVENTS);
- if (unlikely(val > SOFTLIMIT_EVENTS_THRESH)) {
- __mem_cgroup_stat_reset_safe(cpustat, MEM_CGROUP_STAT_EVENTS);
+ val = __mem_cgroup_stat_read_local(cpustat, MEM_CGROUP_STAT_SOFTLIMIT);
+ if (unlikely(val < 0)) {
+ __mem_cgroup_stat_set_safe(cpustat, MEM_CGROUP_STAT_SOFTLIMIT,
+ SOFTLIMIT_EVENTS_THRESH);
ret = true;
}
put_cpu();
@@ -546,7 +548,7 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *mem,
else
__mem_cgroup_stat_add_safe(cpustat,
MEM_CGROUP_STAT_PGPGOUT_COUNT, 1);
- __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_EVENTS, 1);
+ __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_SOFTLIMIT, -1);
put_cpu();
}