Re: [RFC][PATCH 5/6] fix inactive_ratio under hierarchy

From: KAMEZAWA Hiroyuki
Date: Wed Dec 10 2008 - 22:20:47 EST


On Thu, 11 Dec 2008 12:14:04 +0900 (JST)
KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> wrote:

> Hi
>
> > ex)In following tree,
> > /opt/cgroup/01 limit=1G
> > /opt/cgroup/01/A limit=500M
> > /opt/cgroup/01/A/B limit=unlimited
> > /opt/cgroup/01/A/C limit=50M
> > /opt/cgroup/01/Z limit=700M
> >
> >
> > /opt/cgroup/01's inactive_ratio is calculated by limit of 1G.
> > /opt/cgroup/01/A's inactive_ratio is calculated by limit of 500M
> > /opt/cgroup/01/A/B's inactive_ratio is calculated by limit of 500M.
> > /opt/cgroup/01/A/C's inactive_ratio is calculated by limit of 50M.
> > /opt/cgroup/01's inactive_ratio is calculated by limit of 700M.
>
> this is one of good choice.
> but I think it is a bit complex rule.
>
>
> How about this?
>
> ===============
> Currently, inactive_ratio of memcg is calculated at setting limit.
> because page_alloc.c does so and current implementation is straightforward porting.
>
> However, memcg introduced hierarchy feature recently.
> In hierarchy restriction, memory limit is not only decided memory.limit_in_bytes of current cgroup,
> but also parent limit and sibling memory usage.
>
> Then, The optimal inactive_ratio is changed frequently.
> So, everytime calculation is better.
>
thx, I'll test this.

-Kame



>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
> CC: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> CC: Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 3 --
> mm/memcontrol.c | 64 +++++++++++++++++++++------------------------
> mm/vmscan.c | 2 -
> 3 files changed, 33 insertions(+), 36 deletions(-)
>
> Index: b/include/linux/memcontrol.h
> ===================================================================
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -95,8 +95,7 @@ extern void mem_cgroup_note_reclaim_prio
> int priority);
> extern void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem,
> int priority);
> -int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg,
> - struct zone *zone);
> +int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg);
> unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg,
> struct zone *zone,
> enum lru_list lru);
> Index: b/mm/memcontrol.c
> ===================================================================
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -167,9 +167,6 @@ struct mem_cgroup {
>
> unsigned int swappiness;
>
> -
> - unsigned int inactive_ratio;
> -
> /*
> * statistics. This must be placed at the end of memcg.
> */
> @@ -433,15 +430,43 @@ void mem_cgroup_record_reclaim_priority(
> spin_unlock(&mem->reclaim_param_lock);
> }
>
> -int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
> +static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages)
> {
> unsigned long active;
> unsigned long inactive;
> + unsigned long gb;
> + unsigned long inactive_ratio;
>
> inactive = mem_cgroup_get_all_zonestat(memcg, LRU_INACTIVE_ANON);
> active = mem_cgroup_get_all_zonestat(memcg, LRU_ACTIVE_ANON);
>
> - if (inactive * memcg->inactive_ratio < active)
> + gb = (inactive + active) >> (30 - PAGE_SHIFT);
> + if (gb)
> + inactive_ratio = int_sqrt(10 * gb);
> + else
> + inactive_ratio = 1;
> +
> + if (present_pages) {
> + present_pages[0] = inactive;
> + present_pages[1] = active;
> + }
> +
> + return inactive_ratio;
> +}
> +
> +int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg)
> +{
> + unsigned long active;
> + unsigned long inactive;
> + unsigned long present_pages[2];
> + unsigned long inactive_ratio;
> +
> + inactive_ratio = calc_inactive_ratio(memcg, present_pages);
> +
> + inactive = present_pages[0];
> + active = present_pages[1];
> +
> + if (inactive * inactive_ratio < active)
> return 1;
>
> return 0;
> @@ -1410,29 +1435,6 @@ int mem_cgroup_shrink_usage(struct mm_st
> return 0;
> }
>
> -/*
> - * The inactive anon list should be small enough that the VM never has to
> - * do too much work, but large enough that each inactive page has a chance
> - * to be referenced again before it is swapped out.
> - *
> - * this calculation is straightforward porting from
> - * page_alloc.c::setup_per_zone_inactive_ratio().
> - * it describe more detail.
> - */
> -static void mem_cgroup_set_inactive_ratio(struct mem_cgroup *memcg)
> -{
> - unsigned int gb, ratio;
> -
> - gb = res_counter_read_u64(&memcg->res, RES_LIMIT) >> 30;
> - if (gb)
> - ratio = int_sqrt(10 * gb);
> - else
> - ratio = 1;
> -
> - memcg->inactive_ratio = ratio;
> -
> -}
> -
> static DEFINE_MUTEX(set_limit_mutex);
>
> static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> @@ -1472,9 +1474,6 @@ static int mem_cgroup_resize_limit(struc
> if (!progress) retry_count--;
> }
>
> - if (!ret)
> - mem_cgroup_set_inactive_ratio(memcg);
> -
> return ret;
> }
>
> @@ -1833,7 +1832,7 @@ static int mem_control_stat_show(struct
> }
>
> #ifdef CONFIG_DEBUG_VM
> - cb->fill(cb, "inactive_ratio", mem_cont->inactive_ratio);
> + cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL));
>
> {
> int nid, zid;
> @@ -2125,7 +2124,6 @@ mem_cgroup_create(struct cgroup_subsys *
> res_counter_init(&mem->res, NULL);
> res_counter_init(&mem->memsw, NULL);
> }
> - mem_cgroup_set_inactive_ratio(mem);
> mem->last_scanned_child = NULL;
> spin_lock_init(&mem->reclaim_param_lock);
>
> Index: b/mm/vmscan.c
> ===================================================================
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1394,7 +1394,7 @@ static int inactive_anon_is_low(struct z
> if (scanning_global_lru(sc))
> low = inactive_anon_is_low_global(zone);
> else
> - low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup, zone);
> + low = mem_cgroup_inactive_anon_is_low(sc->mem_cgroup);
> return low;
> }
>
>
>
>

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