* KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2011-03-04 16:44:50]:
> From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
>
> memcg: Fix event counter, event leak with THP
>
> With THP, event counter is updated by the size of large page because
> event counter is for catching the change in usage.
> This is now used for threshold notifier and soft limit.
>
> Current event counter cathces the event by mask, as
>
> !(counter & mask)
>
> Before THP, counter is always updated by 1, this never misses target.
> But now, this can miss.
>
> This patch makes the trigger for event as
>
> counter > target.
>
> target is updated when the event happens.
>
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> mm/memcontrol.c | 59 ++++++++++++++++++++++++++++++++++++++++++--------------
> 1 file changed, 45 insertions(+), 14 deletions(-)
>
> Index: mmotm-0303/mm/memcontrol.c
> ===================================================================
> --- mmotm-0303.orig/mm/memcontrol.c
> +++ mmotm-0303/mm/memcontrol.c
> @@ -73,15 +73,6 @@ static int really_do_swap_account __init
> #define do_swap_account (0)
> #endif
>
> -/*
> - * Per memcg event counter is incremented at every pagein/pageout. This counter
> - * is used for trigger some periodic events. This is straightforward and better
> - * than using jiffies etc. to handle periodic memcg event.
> - *
> - * These values will be used as !((event) & ((1 <<(thresh)) - 1))
> - */
> -#define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */
> -#define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */
>
> /*
> * Statistics for memory cgroup.
> @@ -105,10 +96,24 @@ enum mem_cgroup_events_index {
> MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */
> MEM_CGROUP_EVENTS_NSTATS,
> };
> +/*
> + * Per memcg event counter is incremented at every pagein/pageout. With THP,
> + * it will be incremated by the number of pages. This counter is used for
> + * for trigger some periodic events. This is straightforward and better
> + * than using jiffies etc. to handle periodic memcg event.
> + */
> +enum mem_cgroup_events_target {
> + MEM_CGROUP_TARGET_THRESH,
> + MEM_CGROUP_TARGET_SOFTLIMIT,
> + MEM_CGROUP_NTARGETS,
> +};
> +#define THRESHOLDS_EVENTS_TARGET (128)
> +#define SOFTLIMIT_EVENTS_TARGET (1024)
>
> struct mem_cgroup_stat_cpu {
> long count[MEM_CGROUP_STAT_NSTATS];
> unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
> + unsigned long targets[MEM_CGROUP_NTARGETS];
I see spaces as opposed to tabs.
> };
>
> /*
> @@ -634,13 +639,34 @@ static unsigned long mem_cgroup_get_loca
> return total;
> }
>
> -static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
> +static bool __memcg_event_check(struct mem_cgroup *mem, int target)
> {
> - unsigned long val;
> + unsigned long val, next;
>
> val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
> + next = this_cpu_read(mem->stat->targets[target]);
> + /* from time_after() in jiffies.h */
> + return ((long)next - (long)val < 0);
> +}
>
> - return !(val & ((1 << event_mask_shift) - 1));
> +static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target)
> +{
> + unsigned long val, next;
> +
> + val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]);
> +
> + switch (target) {
The formatting seems to be off, could you please check the coding
style
> + case MEM_CGROUP_TARGET_THRESH:
> + next = val + THRESHOLDS_EVENTS_TARGET;
> + break;
> + case MEM_CGROUP_TARGET_SOFTLIMIT:
> + next = val + SOFTLIMIT_EVENTS_TARGET;
> + break;
> + default:
> + return;
> + }
> +
> + this_cpu_write(mem->stat->targets[target], next);
> }
>
> /*
> @@ -650,10 +676,15 @@ static bool __memcg_event_check(struct m
> static void memcg_check_events(struct mem_cgroup *mem, struct page *page)
> {
> /* threshold event is triggered in finer grain than soft limit */
> - if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) {
> + if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) {
> mem_cgroup_threshold(mem);
> - if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
> + __mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH);
> + if (unlikely(__memcg_event_check(mem,
> + MEM_CGROUP_TARGET_SOFTLIMIT))){
> mem_cgroup_update_tree(mem, page);
> + __mem_cgroup_target_update(mem,
> + MEM_CGROUP_TARGET_SOFTLIMIT);
> + }
> }
> }
>
>
--
Three Cheers,
Balbir
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxxx For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>