On Fri, 12 Feb 2010 20:48:10 +0900
Daisuke Nishimura <d-nishimura@xxxxxxxxxxxxxxxxx> wrote:
> On Fri, 12 Feb 2010 18:09:52 +0900
> KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote:
>
> > Memcg has 2 eventcountes which counts "the same" event. Just usages are
> > different from each other. This patch tries to reduce event counter.
> >
> > Now logic uses "only increment, no reset" counter and masks for each
> > checks. Softlimit chesk was done per 1000 evetns. So, the similar check
> > can be done by !(new_counter & 0x3ff). Threshold check was done per 100
> > events. So, the similar check can be done by (!new_counter & 0x7f)
> >
> > ALL event checks are done right after EVENT percpu counter is updated.
> >
> > Changelog: 2010/02/12
> > - fixed to use "inc" rather than "dec"
> > - modified to be more unified style of counter handling.
> > - taking care of account-move.
> >
> > Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
> > Cc: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> > Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
> > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> > ---
> > mm/memcontrol.c | 86 ++++++++++++++++++++++++++------------------------------
> > 1 file changed, 41 insertions(+), 45 deletions(-)
> >
> > Index: mmotm-2.6.33-Feb10/mm/memcontrol.c
> > ===================================================================
> > --- mmotm-2.6.33-Feb10.orig/mm/memcontrol.c
> > +++ mmotm-2.6.33-Feb10/mm/memcontrol.c
> > @@ -63,8 +63,15 @@ static int really_do_swap_account __init
> > #define do_swap_account (0)
> > #endif
> >
> > -#define SOFTLIMIT_EVENTS_THRESH (1000)
> > -#define THRESHOLDS_EVENTS_THRESH (100)
> > +/*
> > + * 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.
> > @@ -79,10 +86,7 @@ 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_SWAPOUT, /* # of pages, swapped out */
> > - MEM_CGROUP_STAT_SOFTLIMIT, /* decrements on each page in/out.
> > - used by soft limit implementation */
> > - MEM_CGROUP_STAT_THRESHOLDS, /* decrements on each page in/out.
> > - used by threshold implementation */
> > + MEM_CGROUP_EVENTS, /* incremented at every pagein/pageout */
> >
> > MEM_CGROUP_STAT_NSTATS,
> > };
> > @@ -154,7 +158,6 @@ struct mem_cgroup_threshold_ary {
> > struct mem_cgroup_threshold entries[0];
> > };
> >
> > -static bool mem_cgroup_threshold_check(struct mem_cgroup *mem);
> > static void mem_cgroup_threshold(struct mem_cgroup *mem);
> >
> > /*
> > @@ -392,19 +395,6 @@ mem_cgroup_remove_exceeded(struct mem_cg
> > spin_unlock(&mctz->lock);
> > }
> >
> > -static bool mem_cgroup_soft_limit_check(struct mem_cgroup *mem)
> > -{
> > - bool ret = false;
> > - s64 val;
> > -
> > - val = this_cpu_read(mem->stat->count[MEM_CGROUP_STAT_SOFTLIMIT]);
> > - if (unlikely(val < 0)) {
> > - this_cpu_write(mem->stat->count[MEM_CGROUP_STAT_SOFTLIMIT],
> > - SOFTLIMIT_EVENTS_THRESH);
> > - ret = true;
> > - }
> > - return ret;
> > -}
> >
> > static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page)
> > {
> > @@ -542,8 +532,7 @@ static void mem_cgroup_charge_statistics
> > __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]);
> > else
> > __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]);
> > - __this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_SOFTLIMIT]);
> > - __this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_THRESHOLDS]);
> > + __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]);
> >
> > preempt_enable();
> > }
> > @@ -563,6 +552,29 @@ static unsigned long mem_cgroup_get_loca
> > return total;
> > }
> >
> > +static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift)
> > +{
> > + s64 val;
> > +
> > + val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]);
> > +
> > + return !(val & ((1 << event_mask_shift) - 1));
> > +}
> > +
> > +/*
> > + * Check events in order.
> > + *
> > + */
> > +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))) {
> > + mem_cgroup_threshold(mem);
> > + if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH)))
> > + mem_cgroup_update_tree(mem, page);
> > + }
> > +}
> > +
> > static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
> > {
> > return container_of(cgroup_subsys_state(cont,
> > @@ -1686,11 +1698,7 @@ static void __mem_cgroup_commit_charge(s
> > * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
> > * if they exceeds softlimit.
> > */
> > - if (mem_cgroup_soft_limit_check(mem))
> > - mem_cgroup_update_tree(mem, pc->page);
> > - if (mem_cgroup_threshold_check(mem))
> > - mem_cgroup_threshold(mem);
> > -
> > + memcg_check_events(mem, pc->page);
> > }
> >
> > /**
> > @@ -1760,6 +1768,11 @@ static int mem_cgroup_move_account(struc
> > ret = 0;
> > }
> > unlock_page_cgroup(pc);
> > + /*
> > + * check events
> > + */
> > + memcg_check_events(to, pc->page);
> > + memcg_check_events(from, pc->page);
> > return ret;
> > }
> >
> Strictly speaking, "if (!ret)" would be needed(it's not a big deal, though).
>
Hmm. ok. I'll check.
Thanks,
-kame
> Thanks,
> Daisuke Nishimura.
>
> > @@ -2128,10 +2141,7 @@ __mem_cgroup_uncharge_common(struct page
> > mz = page_cgroup_zoneinfo(pc);
> > unlock_page_cgroup(pc);
> >
> > - if (mem_cgroup_soft_limit_check(mem))
> > - mem_cgroup_update_tree(mem, page);
> > - if (mem_cgroup_threshold_check(mem))
> > - mem_cgroup_threshold(mem);
> > + memcg_check_events(mem, page);
> > /* at swapout, this memcg will be accessed to record to swap */
> > if (ctype != MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
> > css_put(&mem->css);
> > @@ -3207,20 +3217,6 @@ static int mem_cgroup_swappiness_write(s
> > return 0;
> > }
> >
> > -static bool mem_cgroup_threshold_check(struct mem_cgroup *mem)
> > -{
> > - bool ret = false;
> > - s64 val;
> > -
> > - val = this_cpu_read(mem->stat->count[MEM_CGROUP_STAT_THRESHOLDS]);
> > - if (unlikely(val < 0)) {
> > - this_cpu_write(mem->stat->count[MEM_CGROUP_STAT_THRESHOLDS],
> > - THRESHOLDS_EVENTS_THRESH);
> > - ret = true;
> > - }
> > - return ret;
> > -}
> > -
> > static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
> > {
> > struct mem_cgroup_threshold_ary *t;
> >
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>
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