Messages in this thread Patch in this message | | | Date | Fri, 27 Mar 2009 14:05:28 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | [RFC][PATCH 3/8] trigger for updating soft limit information |
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From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Check/Update softlimit information at every charge is over-killing, so we need some filter.
This patch tries to count events in the memcg and if events > threshold tries to update memcg's soft limit status and reset event counter to 0. Both of page-in/out is counted as event.
Event counter is maintained by per-cpu which has been already used, Then, no siginificant overhead(extra cache-miss etc..) in theory.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> --- Index: mmotm-2.6.29-Mar23/mm/memcontrol.c =================================================================== --- mmotm-2.6.29-Mar23.orig/mm/memcontrol.c +++ mmotm-2.6.29-Mar23/mm/memcontrol.c @@ -66,6 +66,7 @@ enum mem_cgroup_stat_index { MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ + MEM_CGROUP_STAT_EVENTS, /* sum of page-in/page-out for internal use */ MEM_CGROUP_STAT_NSTATS, }; @@ -105,6 +106,22 @@ static s64 mem_cgroup_local_usage(struct return ret; } +/* For intenal use of per-cpu event counting. */ + +static inline void +__mem_cgroup_stat_reset_safe(struct mem_cgroup_stat_cpu *stat, + enum mem_cgroup_stat_index idx) +{ + stat->count[idx] = 0; +} + +static inline s64 +__mem_cgroup_stat_read_local(struct mem_cgroup_stat_cpu *stat, + enum mem_cgroup_stat_index idx) +{ + return stat->count[idx]; +} + /* * per-zone information in memory controller. */ @@ -235,6 +252,8 @@ static void mem_cgroup_charge_statistics else __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_PGPGOUT_COUNT, 1); + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_EVENTS, 1); + put_cpu(); } @@ -897,9 +916,26 @@ static void record_last_oom(struct mem_c mem_cgroup_walk_tree(mem, NULL, record_last_oom_cb); } +#define SOFTLIMIT_EVENTS_THRESH (1024) /* 1024 times of page-in/out */ +/* + * Returns true if sum of page-in/page-out events since last check is + * over SOFTLIMIT_EVENT_THRESH. (counter is per-cpu.) + */ static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem) { - return false; + bool ret = false; + int cpu = get_cpu(); + s64 val; + struct mem_cgroup_stat_cpu *cpustat; + + 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); + ret = true; + } + put_cpu(); + return ret; } static void mem_cgroup_update_soft_limit(struct mem_cgroup *mem)
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