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SubjectRe: [PATCH] memcg: rework inactive_ratio logic
On Wed, 15 Feb 2012 20:24:42 +0400
Konstantin Khlebnikov <khlebnikov@openvz.org> wrote:

> This patch adds mem_cgroup->inactive_ratio calculated from hierarchical memory limit.
> It updated at each limit change before shrinking cgroup to this new limit.
> Ratios for all child cgroups are updated too, because parent limit can affect them.
> Update precedure can be greatly optimized if its performance becomes the problem.
> Inactive ratio for unlimited or huge limit does not matter, because we'll never hit it.
>
> At global reclaim always use global ratio from zone->inactive_ratio.
> At mem-cgroup reclaim use inactive_ratio from target memory cgroup,
> this is cgroup which hit its limit and cause this reclaimer invocation.
>
> Thus, global memory reclaimer will try to keep ratio for all lru lists in zone
> above one mark, this guarantee that total ratio in this zone will be above too.
> Meanwhile mem-cgroup will do the same thing for its lru lists in all zones, and
> for all lru lists in all sub-cgroups in hierarchy.
>
> Also this patch removes some redundant code.
>
> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>

Hmm, the main purpose of this patch is to remove calculation per get_scan_ratio() ?




> ---
> include/linux/memcontrol.h | 16 ++------
> mm/memcontrol.c | 85 ++++++++++++++++++++++++--------------------
> mm/vmscan.c | 82 +++++++++++++++++++++++-------------------
> 3 files changed, 93 insertions(+), 90 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 4d34356..453a3dd 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -113,10 +113,7 @@ void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
> /*
> * For memory reclaim.
> */
> -int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg,
> - struct zone *zone);
> -int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg,
> - struct zone *zone);
> +unsigned int mem_cgroup_inactive_ratio(struct mem_cgroup *memcg);
> int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
> unsigned long mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg,
> int nid, int zid, unsigned int lrumask);
> @@ -319,16 +316,9 @@ static inline bool mem_cgroup_disabled(void)
> return true;
> }
>
> -static inline int
> -mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
> -{
> - return 1;
> -}
> -
> -static inline int
> -mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)
> +static inline unsigned int mem_cgroup_inactive_ratio(struct mem_cgroup *memcg)
> {
> - return 1;
> + return 0;
> }
>
> static inline unsigned long
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 6728a7a..343324a 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -212,6 +212,8 @@ struct mem_cgroup_eventfd_list {
>
> static void mem_cgroup_threshold(struct mem_cgroup *memcg);
> static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
> +static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
> + unsigned long long *mem_limit, unsigned long long *memsw_limit);
>
> /*
> * The memory controller data structure. The memory controller controls both
> @@ -256,6 +258,10 @@ struct mem_cgroup {
> atomic_t refcnt;
>
> int swappiness;
> +
> + /* The target ratio of ACTIVE_ANON to INACTIVE_ANON pages */
> + unsigned int inactive_ratio;
> +
> /* OOM-Killer disable */
> int oom_kill_disable;
>
> @@ -1155,44 +1161,6 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
> return ret;
> }
>
> -int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone)
> -{
> - unsigned long inactive_ratio;
> - int nid = zone_to_nid(zone);
> - int zid = zone_idx(zone);
> - unsigned long inactive;
> - unsigned long active;
> - unsigned long gb;
> -
> - inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
> - BIT(LRU_INACTIVE_ANON));
> - active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
> - BIT(LRU_ACTIVE_ANON));
> -
> - gb = (inactive + active) >> (30 - PAGE_SHIFT);
> - if (gb)
> - inactive_ratio = int_sqrt(10 * gb);
> - else
> - inactive_ratio = 1;
> -
> - return inactive * inactive_ratio < active;
> -}
> -
> -int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone)
> -{
> - unsigned long active;
> - unsigned long inactive;
> - int zid = zone_idx(zone);
> - int nid = zone_to_nid(zone);
> -
> - inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
> - BIT(LRU_INACTIVE_FILE));
> - active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
> - BIT(LRU_ACTIVE_FILE));
> -
> - return (active > inactive);
> -}
> -
> struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg,
> struct zone *zone)
> {
> @@ -3373,6 +3341,32 @@ void mem_cgroup_print_bad_page(struct page *page)
>
> static DEFINE_MUTEX(set_limit_mutex);
>
> +/*
> + * Update inactive_ratio accoring to new memory limit
> + */
> +static void mem_cgroup_update_inactive_ratio(struct mem_cgroup *memcg,
> + unsigned long long target)
> +{
> + unsigned long long mem_limit, memsw_limit, gb;
> + struct mem_cgroup *iter;
> +
> + for_each_mem_cgroup_tree(iter, memcg) {
> + memcg_get_hierarchical_limit(iter, &mem_limit, &memsw_limit);
> + mem_limit = min(mem_limit, target);
> +
> + gb = mem_limit >> 30;
> + if (gb && 10 * gb < INT_MAX)
> + iter->inactive_ratio = int_sqrt(10 * gb);
> + else
> + iter->inactive_ratio = 1;
> + }
> +}
> +
> +unsigned int mem_cgroup_inactive_ratio(struct mem_cgroup *memcg)
> +{
> + return memcg->inactive_ratio;
> +}
> +
> static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> unsigned long long val)
> {
> @@ -3422,6 +3416,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> else
> memcg->memsw_is_minimum = false;
> }
> + mem_cgroup_update_inactive_ratio(memcg, val);
> mutex_unlock(&set_limit_mutex);
>
> if (!ret)
> @@ -3439,6 +3434,12 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
> if (!ret && enlarge)
> memcg_oom_recover(memcg);
>
> + if (ret) {
> + mutex_lock(&set_limit_mutex);
> + mem_cgroup_update_inactive_ratio(memcg, RESOURCE_MAX);
> + mutex_unlock(&set_limit_mutex);
> + }

Why RESOUECE_MAX ?

Thanks,
-Kame

> +
> return ret;
> }
>
> @@ -4155,6 +4156,8 @@ static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
> }
>
> #ifdef CONFIG_DEBUG_VM
> + cb->fill(cb, "inactive_ratio", mem_cont->inactive_ratio);
> +
> {
> int nid, zid;
> struct mem_cgroup_per_zone *mz;
> @@ -4936,8 +4939,12 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
> memcg->last_scanned_node = MAX_NUMNODES;
> INIT_LIST_HEAD(&memcg->oom_notify);
>
> - if (parent)
> + if (parent) {
> memcg->swappiness = mem_cgroup_swappiness(parent);
> + memcg->inactive_ratio = parent->inactive_ratio;
> + } else
> + memcg->inactive_ratio = 1;
> +
> atomic_set(&memcg->refcnt, 1);
> memcg->move_charge_at_immigrate = 0;
> mutex_init(&memcg->thresholds_lock);
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 4061e91..531abcc 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -1788,19 +1788,6 @@ static void shrink_active_list(unsigned long nr_to_scan,
> }
>
> #ifdef CONFIG_SWAP
> -static int inactive_anon_is_low_global(struct zone *zone)
> -{
> - unsigned long active, inactive;
> -
> - active = zone_page_state(zone, NR_ACTIVE_ANON);
> - inactive = zone_page_state(zone, NR_INACTIVE_ANON);
> -
> - if (inactive * zone->inactive_ratio < active)
> - return 1;
> -
> - return 0;
> -}
> -
> /**
> * inactive_anon_is_low - check if anonymous pages need to be deactivated
> * @zone: zone to check
> @@ -1809,8 +1796,12 @@ static int inactive_anon_is_low_global(struct zone *zone)
> * Returns true if the zone does not have enough inactive anon pages,
> * meaning some active anon pages need to be deactivated.
> */
> -static int inactive_anon_is_low(struct mem_cgroup_zone *mz)
> +static int inactive_anon_is_low(struct mem_cgroup_zone *mz,
> + struct scan_control *sc)
> {
> + unsigned long active, inactive;
> + unsigned int ratio;
> +
> /*
> * If we don't have swap space, anonymous page deactivation
> * is pointless.
> @@ -1818,29 +1809,33 @@ static int inactive_anon_is_low(struct mem_cgroup_zone *mz)
> if (!total_swap_pages)
> return 0;
>
> - if (!scanning_global_lru(mz))
> - return mem_cgroup_inactive_anon_is_low(mz->mem_cgroup,
> - mz->zone);
> + if (global_reclaim(sc))
> + ratio = mz->zone->inactive_ratio;
> + else
> + ratio = mem_cgroup_inactive_ratio(sc->target_mem_cgroup);
>
> - return inactive_anon_is_low_global(mz->zone);
> + if (scanning_global_lru(mz)) {
> + active = zone_page_state(mz->zone, NR_ACTIVE_ANON);
> + inactive = zone_page_state(mz->zone, NR_INACTIVE_ANON);
> + } else {
> + active = mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
> + zone_to_nid(mz->zone), zone_idx(mz->zone),
> + BIT(LRU_ACTIVE_ANON));
> + inactive = mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
> + zone_to_nid(mz->zone), zone_idx(mz->zone),
> + BIT(LRU_INACTIVE_ANON));
> + }
> +
> + return inactive * ratio < active;
> }
> #else
> -static inline int inactive_anon_is_low(struct mem_cgroup_zone *mz)
> +static inline int inactive_anon_is_low(struct mem_cgroup_zone *mz,
> + struct scan_control *sc)
> {
> return 0;
> }
> #endif
>
> -static int inactive_file_is_low_global(struct zone *zone)
> -{
> - unsigned long active, inactive;
> -
> - active = zone_page_state(zone, NR_ACTIVE_FILE);
> - inactive = zone_page_state(zone, NR_INACTIVE_FILE);
> -
> - return (active > inactive);
> -}
> -
> /**
> * inactive_file_is_low - check if file pages need to be deactivated
> * @mz: memory cgroup and zone to check
> @@ -1857,19 +1852,30 @@ static int inactive_file_is_low_global(struct zone *zone)
> */
> static int inactive_file_is_low(struct mem_cgroup_zone *mz)
> {
> - if (!scanning_global_lru(mz))
> - return mem_cgroup_inactive_file_is_low(mz->mem_cgroup,
> - mz->zone);
> + unsigned long active, inactive;
> +
> + if (scanning_global_lru(mz)) {
> + active = zone_page_state(mz->zone, NR_ACTIVE_FILE);
> + inactive = zone_page_state(mz->zone, NR_INACTIVE_FILE);
> + } else {
> + active = mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
> + zone_to_nid(mz->zone), zone_idx(mz->zone),
> + BIT(LRU_ACTIVE_FILE));
> + inactive = mem_cgroup_zone_nr_lru_pages(mz->mem_cgroup,
> + zone_to_nid(mz->zone), zone_idx(mz->zone),
> + BIT(LRU_INACTIVE_FILE));
> + }
>
> - return inactive_file_is_low_global(mz->zone);
> + return inactive < active;
> }
>
> -static int inactive_list_is_low(struct mem_cgroup_zone *mz, int file)
> +static int inactive_list_is_low(struct mem_cgroup_zone *mz,
> + struct scan_control *sc, int file)
> {
> if (file)
> return inactive_file_is_low(mz);
> else
> - return inactive_anon_is_low(mz);
> + return inactive_anon_is_low(mz, sc);
> }
>
> static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
> @@ -1879,7 +1885,7 @@ static unsigned long shrink_list(enum lru_list lru, unsigned long nr_to_scan,
> int file = is_file_lru(lru);
>
> if (is_active_lru(lru)) {
> - if (inactive_list_is_low(mz, file))
> + if (inactive_list_is_low(mz, sc, file))
> shrink_active_list(nr_to_scan, mz, sc, priority, file);
> return 0;
> }
> @@ -2129,7 +2135,7 @@ restart:
> * Even if we did not try to evict anon pages at all, we want to
> * rebalance the anon lru active/inactive ratio.
> */
> - if (inactive_anon_is_low(mz))
> + if (inactive_anon_is_low(mz, sc))
> shrink_active_list(SWAP_CLUSTER_MAX, mz, sc, priority, 0);
>
> /* reclaim/compaction might need reclaim to continue */
> @@ -2558,7 +2564,7 @@ static void age_active_anon(struct zone *zone, struct scan_control *sc,
> .zone = zone,
> };
>
> - if (inactive_anon_is_low(&mz))
> + if (inactive_anon_is_low(&mz, sc))
> shrink_active_list(SWAP_CLUSTER_MAX, &mz,
> sc, priority, 0);
>
>
> --
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