Re: [PATCH 6/8] mm: vmscan: simplify memcg vs. global shrinker invocation

[Michal Hocko]

On Thu 22-10-15 00:21:34, Johannes Weiner wrote:
> Letting shrink_slab() handle the root_mem_cgroup, and implicitely the
> !CONFIG_MEMCG case, allows shrink_zone() to invoke the shrinkers
> unconditionally from within the memcg iteration loop.
> 
> Signed-off-by: Johannes Weiner 

Acked-by: Michal Hocko 

> ---
>  include/linux/memcontrol.h |  2 ++
>  mm/vmscan.c| 31 ---
>  2 files changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 6f1e0f8..d66ae18 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -482,6 +482,8 @@ void mem_cgroup_split_huge_fixup(struct page *head);
>  #else /* CONFIG_MEMCG */
>  struct mem_cgroup;
>  
> +#define root_mem_cgroup NULL
> +
>  static inline void mem_cgroup_events(struct mem_cgroup *memcg,
>enum mem_cgroup_events_index idx,
>unsigned int nr)
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 9b52ecf..ecc2125 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -411,6 +411,10 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
>   struct shrinker *shrinker;
>   unsigned long freed = 0;
>  
> + /* Global shrinker mode */
> + if (memcg == root_mem_cgroup)
> + memcg = NULL;
> +
>   if (memcg && !memcg_kmem_is_active(memcg))
>   return 0;
>  
> @@ -2417,11 +2421,22 @@ static bool shrink_zone(struct zone *zone, struct 
> scan_control *sc,
>   shrink_lruvec(lruvec, swappiness, sc, _pages);
>   zone_lru_pages += lru_pages;
>  
> - if (memcg && is_classzone)
> + /*
> +  * Shrink the slab caches in the same proportion that
> +  * the eligible LRU pages were scanned.
> +  */
> + if (is_classzone) {
>   shrink_slab(sc->gfp_mask, zone_to_nid(zone),
>   memcg, sc->nr_scanned - scanned,
>   lru_pages);
>  
> + if (reclaim_state) {
> + sc->nr_reclaimed +=
> + reclaim_state->reclaimed_slab;
> + reclaim_state->reclaimed_slab = 0;
> + }
> + }
> +
>   /*
>* Direct reclaim and kswapd have to scan all memory
>* cgroups to fulfill the overall scan target for the
> @@ -2439,20 +2454,6 @@ static bool shrink_zone(struct zone *zone, struct 
> scan_control *sc,
>   }
>   } while ((memcg = mem_cgroup_iter(root, memcg, )));
>  
> - /*
> -  * Shrink the slab caches in the same proportion that
> -  * the eligible LRU pages were scanned.
> -  */
> - if (global_reclaim(sc) && is_classzone)
> - shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
> - sc->nr_scanned - nr_scanned,
> - zone_lru_pages);
> -
> - if (reclaim_state) {
> - sc->nr_reclaimed += reclaim_state->reclaimed_slab;
> - reclaim_state->reclaimed_slab = 0;
> - }
> -
>   vmpressure(sc->gfp_mask, sc->target_mem_cgroup,
>  sc->nr_scanned - nr_scanned,
>  sc->nr_reclaimed - nr_reclaimed);
> -- 
> 2.6.1

-- 
Michal Hocko
SUSE Labs
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Re: [PATCH 6/8] mm: vmscan: simplify memcg vs. global shrinker invocation

[Michal Hocko]

On Thu 22-10-15 00:21:34, Johannes Weiner wrote:
> Letting shrink_slab() handle the root_mem_cgroup, and implicitely the
> !CONFIG_MEMCG case, allows shrink_zone() to invoke the shrinkers
> unconditionally from within the memcg iteration loop.
> 
> Signed-off-by: Johannes Weiner 

Acked-by: Michal Hocko 

> ---
>  include/linux/memcontrol.h |  2 ++
>  mm/vmscan.c| 31 ---
>  2 files changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 6f1e0f8..d66ae18 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -482,6 +482,8 @@ void mem_cgroup_split_huge_fixup(struct page *head);
>  #else /* CONFIG_MEMCG */
>  struct mem_cgroup;
>  
> +#define root_mem_cgroup NULL
> +
>  static inline void mem_cgroup_events(struct mem_cgroup *memcg,
>enum mem_cgroup_events_index idx,
>unsigned int nr)
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 9b52ecf..ecc2125 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -411,6 +411,10 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
>   struct shrinker *shrinker;
>   unsigned long freed = 0;
>  
> + /* Global shrinker mode */
> + if (memcg == root_mem_cgroup)
> + memcg = NULL;
> +
>   if (memcg && !memcg_kmem_is_active(memcg))
>   return 0;
>  
> @@ -2417,11 +2421,22 @@ static bool shrink_zone(struct zone *zone, struct 
> scan_control *sc,
>   shrink_lruvec(lruvec, swappiness, sc, _pages);
>   zone_lru_pages += lru_pages;
>  
> - if (memcg && is_classzone)
> + /*
> +  * Shrink the slab caches in the same proportion that
> +  * the eligible LRU pages were scanned.
> +  */
> + if (is_classzone) {
>   shrink_slab(sc->gfp_mask, zone_to_nid(zone),
>   memcg, sc->nr_scanned - scanned,
>   lru_pages);
>  
> + if (reclaim_state) {
> + sc->nr_reclaimed +=
> + reclaim_state->reclaimed_slab;
> + reclaim_state->reclaimed_slab = 0;
> + }
> + }
> +
>   /*
>* Direct reclaim and kswapd have to scan all memory
>* cgroups to fulfill the overall scan target for the
> @@ -2439,20 +2454,6 @@ static bool shrink_zone(struct zone *zone, struct 
> scan_control *sc,
>   }
>   } while ((memcg = mem_cgroup_iter(root, memcg, )));
>  
> - /*
> -  * Shrink the slab caches in the same proportion that
> -  * the eligible LRU pages were scanned.
> -  */
> - if (global_reclaim(sc) && is_classzone)
> - shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
> - sc->nr_scanned - nr_scanned,
> - zone_lru_pages);
> -
> - if (reclaim_state) {
> - sc->nr_reclaimed += reclaim_state->reclaimed_slab;
> - reclaim_state->reclaimed_slab = 0;
> - }
> -
>   vmpressure(sc->gfp_mask, sc->target_mem_cgroup,
>  sc->nr_scanned - nr_scanned,
>  sc->nr_reclaimed - nr_reclaimed);
> -- 
> 2.6.1

-- 
Michal Hocko
SUSE Labs
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[PATCH 6/8] mm: vmscan: simplify memcg vs. global shrinker invocation

[Johannes Weiner]

Letting shrink_slab() handle the root_mem_cgroup, and implicitely the
!CONFIG_MEMCG case, allows shrink_zone() to invoke the shrinkers
unconditionally from within the memcg iteration loop.

Signed-off-by: Johannes Weiner 
---
 include/linux/memcontrol.h |  2 ++
 mm/vmscan.c| 31 ---
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6f1e0f8..d66ae18 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -482,6 +482,8 @@ void mem_cgroup_split_huge_fixup(struct page *head);
 #else /* CONFIG_MEMCG */
 struct mem_cgroup;
 
+#define root_mem_cgroup NULL
+
 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 enum mem_cgroup_events_index idx,
 unsigned int nr)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9b52ecf..ecc2125 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -411,6 +411,10 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
struct shrinker *shrinker;
unsigned long freed = 0;
 
+   /* Global shrinker mode */
+   if (memcg == root_mem_cgroup)
+   memcg = NULL;
+
if (memcg && !memcg_kmem_is_active(memcg))
return 0;
 
@@ -2417,11 +2421,22 @@ static bool shrink_zone(struct zone *zone, struct 
scan_control *sc,
shrink_lruvec(lruvec, swappiness, sc, _pages);
zone_lru_pages += lru_pages;
 
-   if (memcg && is_classzone)
+   /*
+* Shrink the slab caches in the same proportion that
+* the eligible LRU pages were scanned.
+*/
+   if (is_classzone) {
shrink_slab(sc->gfp_mask, zone_to_nid(zone),
memcg, sc->nr_scanned - scanned,
lru_pages);
 
+   if (reclaim_state) {
+   sc->nr_reclaimed +=
+   reclaim_state->reclaimed_slab;
+   reclaim_state->reclaimed_slab = 0;
+   }
+   }
+
/*
 * Direct reclaim and kswapd have to scan all memory
 * cgroups to fulfill the overall scan target for the
@@ -2439,20 +2454,6 @@ static bool shrink_zone(struct zone *zone, struct 
scan_control *sc,
}
} while ((memcg = mem_cgroup_iter(root, memcg, )));
 
-   /*
-* Shrink the slab caches in the same proportion that
-* the eligible LRU pages were scanned.
-*/
-   if (global_reclaim(sc) && is_classzone)
-   shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
-   sc->nr_scanned - nr_scanned,
-   zone_lru_pages);
-
-   if (reclaim_state) {
-   sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-   reclaim_state->reclaimed_slab = 0;
-   }
-
vmpressure(sc->gfp_mask, sc->target_mem_cgroup,
   sc->nr_scanned - nr_scanned,
   sc->nr_reclaimed - nr_reclaimed);
-- 
2.6.1

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Please read the FAQ at  http://www.tux.org/lkml/

[PATCH 6/8] mm: vmscan: simplify memcg vs. global shrinker invocation

[Johannes Weiner]

Letting shrink_slab() handle the root_mem_cgroup, and implicitely the
!CONFIG_MEMCG case, allows shrink_zone() to invoke the shrinkers
unconditionally from within the memcg iteration loop.

Signed-off-by: Johannes Weiner 
---
 include/linux/memcontrol.h |  2 ++
 mm/vmscan.c| 31 ---
 2 files changed, 18 insertions(+), 15 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 6f1e0f8..d66ae18 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -482,6 +482,8 @@ void mem_cgroup_split_huge_fixup(struct page *head);
 #else /* CONFIG_MEMCG */
 struct mem_cgroup;
 
+#define root_mem_cgroup NULL
+
 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 enum mem_cgroup_events_index idx,
 unsigned int nr)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9b52ecf..ecc2125 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -411,6 +411,10 @@ static unsigned long shrink_slab(gfp_t gfp_mask, int nid,
struct shrinker *shrinker;
unsigned long freed = 0;
 
+   /* Global shrinker mode */
+   if (memcg == root_mem_cgroup)
+   memcg = NULL;
+
if (memcg && !memcg_kmem_is_active(memcg))
return 0;
 
@@ -2417,11 +2421,22 @@ static bool shrink_zone(struct zone *zone, struct 
scan_control *sc,
shrink_lruvec(lruvec, swappiness, sc, _pages);
zone_lru_pages += lru_pages;
 
-   if (memcg && is_classzone)
+   /*
+* Shrink the slab caches in the same proportion that
+* the eligible LRU pages were scanned.
+*/
+   if (is_classzone) {
shrink_slab(sc->gfp_mask, zone_to_nid(zone),
memcg, sc->nr_scanned - scanned,
lru_pages);
 
+   if (reclaim_state) {
+   sc->nr_reclaimed +=
+   reclaim_state->reclaimed_slab;
+   reclaim_state->reclaimed_slab = 0;
+   }
+   }
+
/*
 * Direct reclaim and kswapd have to scan all memory
 * cgroups to fulfill the overall scan target for the
@@ -2439,20 +2454,6 @@ static bool shrink_zone(struct zone *zone, struct 
scan_control *sc,
}
} while ((memcg = mem_cgroup_iter(root, memcg, )));
 
-   /*
-* Shrink the slab caches in the same proportion that
-* the eligible LRU pages were scanned.
-*/
-   if (global_reclaim(sc) && is_classzone)
-   shrink_slab(sc->gfp_mask, zone_to_nid(zone), NULL,
-   sc->nr_scanned - nr_scanned,
-   zone_lru_pages);
-
-   if (reclaim_state) {
-   sc->nr_reclaimed += reclaim_state->reclaimed_slab;
-   reclaim_state->reclaimed_slab = 0;
-   }
-
vmpressure(sc->gfp_mask, sc->target_mem_cgroup,
   sc->nr_scanned - nr_scanned,
   sc->nr_reclaimed - nr_reclaimed);
-- 
2.6.1

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