Hi Glauber,
On Fri, Mar 29, 2013 at 5:14 PM, Glauber Costa <glommer@xxxxxxxxxxxxx> wrote:
> Without the surrounding infrastructure, this patch is a bit of a hammer:
> it will basically shrink objects from all memcgs under memcg pressure.
> At least, however, we will keep the scan limited to the shrinkers marked
> as per-memcg.
>
> Future patches will implement the in-shrinker logic to filter objects
> based on its memcg association.
>
> Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
> Cc: Dave Chinner <dchinner@xxxxxxxxxx>
> Cc: Mel Gorman <mgorman@xxxxxxx>
> Cc: Rik van Riel <riel@xxxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 17 +++++++++++++++++
> include/linux/shrinker.h | 4 ++++
> mm/memcontrol.c | 16 +++++++++++++++-
> mm/vmscan.c | 46 +++++++++++++++++++++++++++++++++++++++++++---
> 4 files changed, 79 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index d6183f0..4c24249 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -199,6 +199,9 @@ void mem_cgroup_split_huge_fixup(struct page *head);
> bool mem_cgroup_bad_page_check(struct page *page);
> void mem_cgroup_print_bad_page(struct page *page);
> #endif
> +
> +unsigned long
> +memcg_zone_reclaimable_pages(struct mem_cgroup *memcg, struct zone *zone);
> #else /* CONFIG_MEMCG */
> struct mem_cgroup;
>
> @@ -377,6 +380,12 @@ static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
> struct page *newpage)
> {
> }
> +
> +static inline unsigned long
> +memcg_zone_reclaimable_pages(struct mem_cgroup *memcg, struct zone *zone)
> +{
> + return 0;
> +}
> #endif /* CONFIG_MEMCG */
>
> #if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM)
> @@ -429,6 +438,8 @@ static inline bool memcg_kmem_enabled(void)
> return static_key_false(&memcg_kmem_enabled_key);
> }
>
> +bool memcg_kmem_is_active(struct mem_cgroup *memcg);
> +
> /*
> * In general, we'll do everything in our power to not incur in any overhead
> * for non-memcg users for the kmem functions. Not even a function call, if we
> @@ -562,6 +573,12 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
> return __memcg_kmem_get_cache(cachep, gfp);
> }
> #else
> +
> +static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
> +{
> + return false;
> +}
> +
> #define for_each_memcg_cache_index(_idx) \
> for (; NULL; )
>
> diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h
> index d4636a0..4e9e53b 100644
> --- a/include/linux/shrinker.h
> +++ b/include/linux/shrinker.h
> @@ -20,6 +20,9 @@ struct shrink_control {
>
> /* shrink from these nodes */
> nodemask_t nodes_to_scan;
> +
> + /* reclaim from this memcg only (if not NULL) */
> + struct mem_cgroup *target_mem_cgroup;
> };
>
> /*
> @@ -45,6 +48,7 @@ struct shrinker {
>
> int seeks; /* seeks to recreate an obj */
> long batch; /* reclaim batch size, 0 = default */
> + bool memcg_shrinker; /* memcg-aware shrinker */
>
> /* These are for internal use */
> struct list_head list;
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 2b55222..ecdae39 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -386,7 +386,7 @@ static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
> set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
> }
>
> -static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
> +bool memcg_kmem_is_active(struct mem_cgroup *memcg)
> {
> return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
> }
> @@ -942,6 +942,20 @@ mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
> return ret;
> }
>
> +unsigned long
> +memcg_zone_reclaimable_pages(struct mem_cgroup *memcg, struct zone *zone)
> +{
> + int nid = zone_to_nid(zone);
> + int zid = zone_idx(zone);
> + unsigned long val;
> +
> + val = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, LRU_ALL_FILE);
> + if (do_swap_account)
IMHO May get_nr_swap_pages() be more appropriate here?
> + val += mem_cgroup_zone_nr_lru_pages(memcg, nid, zid,
> + LRU_ALL_ANON);
> + return val;
> +}
> +
> static unsigned long
> mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
> int nid, unsigned int lru_mask)
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 232dfcb..43928fd 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -138,11 +138,42 @@ static bool global_reclaim(struct scan_control *sc)
> {
> return !sc->target_mem_cgroup;
> }
> +
> +/*
> + * kmem reclaim should usually not be triggered when we are doing targetted
> + * reclaim. It is only valid when global reclaim is triggered, or when the
> + * underlying memcg has kmem objects.
> + */
> +static bool has_kmem_reclaim(struct scan_control *sc)
> +{
> + return !sc->target_mem_cgroup ||
> + memcg_kmem_is_active(sc->target_mem_cgroup);
> +}
> +
> +static unsigned long
> +zone_nr_reclaimable_pages(struct scan_control *sc, struct zone *zone)
> +{
> + if (global_reclaim(sc))
> + return zone_reclaimable_pages(zone);
> + return memcg_zone_reclaimable_pages(sc->target_mem_cgroup, zone);
> +}
> +
> #else
> static bool global_reclaim(struct scan_control *sc)
> {
> return true;
> }
> +
> +static bool has_kmem_reclaim(struct scan_control *sc)
> +{
> + return true;
> +}
> +
> +static unsigned long
> +zone_nr_reclaimable_pages(struct scan_control *sc, struct zone *zone)
> +{
> + return zone_reclaimable_pages(zone);
> +}
> #endif
>
> static unsigned long get_lru_size(struct lruvec *lruvec, enum lru_list lru)
> @@ -221,6 +252,14 @@ unsigned long shrink_slab(struct shrink_control *sc,
> long batch_size = shrinker->batch ? shrinker->batch
> : SHRINK_BATCH;
>
> + /*
> + * If we don't have a target mem cgroup, we scan them all.
> + * Otherwise we will limit our scan to shrinkers marked as
> + * memcg aware
> + */
> + if (sc->target_mem_cgroup && !shrinker->memcg_shrinker)
> + continue;
> +
> max_pass = shrinker->count_objects(shrinker, sc);
> WARN_ON(max_pass < 0);
> if (max_pass <= 0)
> @@ -2163,9 +2202,9 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
>
> /*
> * Don't shrink slabs when reclaiming memory from
> - * over limit cgroups
> + * over limit cgroups, unless we know they have kmem objects
> */
> - if (global_reclaim(sc)) {
> + if (has_kmem_reclaim(sc)) {
> unsigned long lru_pages = 0;
>
> nodes_clear(shrink->nodes_to_scan);
> @@ -2174,7 +2213,7 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
> if (!cpuset_zone_allowed_hardwall(zone, GFP_KERNEL))
> continue;
>
> - lru_pages += zone_reclaimable_pages(zone);
> + lru_pages += zone_nr_reclaimable_pages(sc, zone);
> node_set(zone_to_nid(zone),
> shrink->nodes_to_scan);
> }
> @@ -2443,6 +2482,7 @@ unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
> };
> struct shrink_control shrink = {
> .gfp_mask = sc.gfp_mask,
> + .target_mem_cgroup = memcg,
> };
>
> /*
> --
> 1.8.1.4
>
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--
Thanks,
Sha
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