[PATCH 3/3] mm: workingset: cgroup-aware
From: Johannes Weiner
Date: Mon Jan 25 2016 - 11:43:37 EST
TODO:
- cgroup-aware shadow node reclaim
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/memcontrol.h | 39 ++++++++++++++++++++++++++++++
include/linux/mmzone.h | 11 ++++-----
include/linux/swap.h | 1 +
mm/memcontrol.c | 25 --------------------
mm/vmscan.c | 18 +++++++-------
mm/workingset.c | 59 +++++++++++++++++++++++++++++++++++++---------
6 files changed, 102 insertions(+), 51 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 792c8981e633..705aba54a50d 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -89,6 +89,10 @@ enum mem_cgroup_events_target {
};
#ifdef CONFIG_MEMCG
+
+#define MEM_CGROUP_ID_SHIFT 16
+#define MEM_CGROUP_ID_MAX USHRT_MAX
+
struct mem_cgroup_stat_cpu {
long count[MEMCG_NR_STAT];
unsigned long events[MEMCG_NR_EVENTS];
@@ -312,6 +316,25 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
struct mem_cgroup_reclaim_cookie *);
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
+static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
+{
+ return memcg->css.id;
+}
+
+/**
+ * mem_cgroup_from_id - look up a memcg from an id
+ * @id: the id to look up
+ *
+ * Caller must hold rcu_read_lock() and use css_tryget() as necessary.
+ */
+static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+ struct cgroup_subsys_state *css;
+
+ css = css_from_id(id, &memory_cgrp_subsys);
+ return mem_cgroup_from_css(css);
+}
+
/**
* parent_mem_cgroup - find the accounting parent of a memcg
* @memcg: memcg whose parent to find
@@ -496,6 +519,10 @@ void mem_cgroup_split_huge_fixup(struct page *head);
#endif
#else /* CONFIG_MEMCG */
+
+#define MEM_CGROUP_ID_SHIFT 0
+#define MEM_CGROUP_ID_MAX 0
+
struct mem_cgroup;
static inline void mem_cgroup_events(struct mem_cgroup *memcg,
@@ -580,6 +607,18 @@ static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
{
}
+static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
+{
+ return 0;
+}
+
+static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+ WARN_ON_ONCE(id);
+ /* XXX: This should always return root_mem_cgroup */
+ return NULL;
+}
+
static inline bool mem_cgroup_disabled(void)
{
return true;
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 33bb1b19273e..a7d8eeb6658a 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -209,10 +209,12 @@ struct zone_reclaim_stat {
};
struct lruvec {
- struct list_head lists[NR_LRU_LISTS];
- struct zone_reclaim_stat reclaim_stat;
+ struct list_head lists[NR_LRU_LISTS];
+ struct zone_reclaim_stat reclaim_stat;
+ /* Evictions & activations on the inactive file list */
+ atomic_long_t inactive_age;
#ifdef CONFIG_MEMCG
- struct zone *zone;
+ struct zone *zone;
#endif
};
@@ -487,9 +489,6 @@ struct zone {
spinlock_t lru_lock;
struct lruvec lruvec;
- /* Evictions & activations on the inactive file list */
- atomic_long_t inactive_age;
-
/*
* When free pages are below this point, additional steps are taken
* when reading the number of free pages to avoid per-cpu counter
diff --git a/include/linux/swap.h b/include/linux/swap.h
index b14a2bb33514..1cf3065c143b 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -317,6 +317,7 @@ extern void lru_cache_add_active_or_unevictable(struct page *page,
/* linux/mm/vmscan.c */
extern unsigned long zone_reclaimable_pages(struct zone *zone);
+extern unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru);
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
extern int __isolate_lru_page(struct page *page, isolate_mode_t mode);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d06cae2de783..4ea79f225fe8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -268,31 +268,6 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
return (memcg == root_mem_cgroup);
}
-/*
- * We restrict the id in the range of [1, 65535], so it can fit into
- * an unsigned short.
- */
-#define MEM_CGROUP_ID_MAX USHRT_MAX
-
-static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
-{
- return memcg->css.id;
-}
-
-/*
- * A helper function to get mem_cgroup from ID. must be called under
- * rcu_read_lock(). The caller is responsible for calling
- * css_tryget_online() if the mem_cgroup is used for charging. (dropping
- * refcnt from swap can be called against removed memcg.)
- */
-static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
-{
- struct cgroup_subsys_state *css;
-
- css = css_from_id(id, &memory_cgrp_subsys);
- return mem_cgroup_from_css(css);
-}
-
#ifndef CONFIG_SLOB
/*
* This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 30e0cd7a0ceb..f4ac04c0d35a 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -213,7 +213,7 @@ bool zone_reclaimable(struct zone *zone)
zone_reclaimable_pages(zone) * 6;
}
-static unsigned long get_lru_size(struct lruvec *lruvec, enum lru_list lru)
+unsigned long lruvec_lru_size(struct lruvec *lruvec, enum lru_list lru)
{
if (!mem_cgroup_disabled())
return mem_cgroup_get_lru_size(lruvec, lru);
@@ -1931,8 +1931,8 @@ static bool inactive_file_is_low(struct lruvec *lruvec)
unsigned long inactive;
unsigned long active;
- inactive = get_lru_size(lruvec, LRU_INACTIVE_FILE);
- active = get_lru_size(lruvec, LRU_ACTIVE_FILE);
+ inactive = lruvec_lru_size(lruvec, LRU_INACTIVE_FILE);
+ active = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
return active > inactive;
}
@@ -2071,7 +2071,7 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
* system is under heavy pressure.
*/
if (!inactive_file_is_low(lruvec) &&
- get_lru_size(lruvec, LRU_INACTIVE_FILE) >> sc->priority) {
+ lruvec_lru_size(lruvec, LRU_INACTIVE_FILE) >> sc->priority) {
scan_balance = SCAN_FILE;
goto out;
}
@@ -2097,10 +2097,10 @@ static void get_scan_count(struct lruvec *lruvec, struct mem_cgroup *memcg,
* anon in [0], file in [1]
*/
- anon = get_lru_size(lruvec, LRU_ACTIVE_ANON) +
- get_lru_size(lruvec, LRU_INACTIVE_ANON);
- file = get_lru_size(lruvec, LRU_ACTIVE_FILE) +
- get_lru_size(lruvec, LRU_INACTIVE_FILE);
+ anon = lruvec_lru_size(lruvec, LRU_ACTIVE_ANON) +
+ lruvec_lru_size(lruvec, LRU_INACTIVE_ANON);
+ file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE) +
+ lruvec_lru_size(lruvec, LRU_INACTIVE_FILE);
spin_lock_irq(&zone->lru_lock);
if (unlikely(reclaim_stat->recent_scanned[0] > anon / 4)) {
@@ -2138,7 +2138,7 @@ out:
unsigned long size;
unsigned long scan;
- size = get_lru_size(lruvec, lru);
+ size = lruvec_lru_size(lruvec, lru);
scan = size >> sc->priority;
if (!scan && pass && force_scan)
diff --git a/mm/workingset.c b/mm/workingset.c
index ac6eb7bc1faa..fe69da29bbad 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -152,7 +152,8 @@
* refault distance will immediately activate the refaulting page.
*/
-#define EVICTION_SHIFT (NODES_SHIFT + ZONES_SHIFT + \
+#define EVICTION_SHIFT (MEM_CGROUP_ID_SHIFT + \
+ NODES_SHIFT + ZONES_SHIFT + \
RADIX_TREE_EXCEPTIONAL_SHIFT)
#define EVICTION_MASK (~0UL >> EVICTION_SHIFT)
@@ -166,9 +167,10 @@
*/
static unsigned int bucket_order;
-static void *pack_shadow(unsigned long eviction, struct zone *zone)
+static void *pack_shadow(int memcgid, struct zone *zone, unsigned long eviction)
{
eviction >>= bucket_order;
+ eviction = (eviction << MEM_CGROUP_ID_SHIFT) | memcgid;
eviction = (eviction << NODES_SHIFT) | zone_to_nid(zone);
eviction = (eviction << ZONES_SHIFT) | zone_idx(zone);
eviction = (eviction << RADIX_TREE_EXCEPTIONAL_SHIFT);
@@ -176,21 +178,23 @@ static void *pack_shadow(unsigned long eviction, struct zone *zone)
return (void *)(eviction | RADIX_TREE_EXCEPTIONAL_ENTRY);
}
-static void unpack_shadow(void *shadow, struct zone **zonep,
+static void unpack_shadow(void *shadow, int *memcgidp, struct zone **zonep,
unsigned long *evictionp)
{
unsigned long entry = (unsigned long)shadow;
- int zid, nid;
+ int memcgid, nid, zid;
entry >>= RADIX_TREE_EXCEPTIONAL_SHIFT;
zid = entry & ((1UL << ZONES_SHIFT) - 1);
entry >>= ZONES_SHIFT;
nid = entry & ((1UL << NODES_SHIFT) - 1);
entry >>= NODES_SHIFT;
+ memcgid = entry & ((1UL << MEM_CGROUP_ID_SHIFT) - 1);
+ entry >>= MEM_CGROUP_ID_SHIFT;
+ *memcgidp = memcgid;
*zonep = NODE_DATA(nid)->node_zones + zid;
*evictionp = entry << bucket_order;
-
}
/**
@@ -203,11 +207,20 @@ static void unpack_shadow(void *shadow, struct zone **zonep,
*/
void *workingset_eviction(struct address_space *mapping, struct page *page)
{
+ struct mem_cgroup *memcg = page_memcg(page);
struct zone *zone = page_zone(page);
+ int memcgid = mem_cgroup_id(memcg);
unsigned long eviction;
+ struct lruvec *lruvec;
+
+ /* Page is fully exclusive and pins page->mem_cgroup */
+ VM_BUG_ON_PAGE(PageLRU(page), page);
+ VM_BUG_ON_PAGE(page_count(page), page);
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
- eviction = atomic_long_inc_return(&zone->inactive_age);
- return pack_shadow(eviction, zone);
+ lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ eviction = atomic_long_inc_return(&lruvec->inactive_age);
+ return pack_shadow(memcgid, zone, eviction);
}
/**
@@ -222,13 +235,32 @@ void *workingset_eviction(struct address_space *mapping, struct page *page)
bool workingset_refault(void *shadow)
{
unsigned long refault_distance;
+ unsigned long active_file;
+ struct mem_cgroup *memcg;
unsigned long eviction;
+ struct lruvec *lruvec;
unsigned long refault;
struct zone *zone;
+ int memcgid;
- unpack_shadow(shadow, &zone, &eviction);
+ unpack_shadow(shadow, &memcgid, &zone, &eviction);
- refault = atomic_long_read(&zone->inactive_age);
+ rcu_read_lock();
+ memcg = mem_cgroup_from_id(memcgid);
+ /*
+ * Don't count a refault if the remembered memcg has been
+ * deleted since. XXX: On !CONFIG_MEMCG, this will always
+ * return NULL; it would be better if the root_mem_cgroup
+ * existed in all configurations instead.
+ */
+ if (!mem_cgroup_disabled() && !memcg) {
+ rcu_read_unlock();
+ return false;
+ }
+ lruvec = mem_cgroup_zone_lruvec(zone, memcg);
+ refault = atomic_long_read(&lruvec->inactive_age);
+ active_file = lruvec_lru_size(lruvec, LRU_ACTIVE_FILE);
+ rcu_read_unlock();
/*
* The unsigned subtraction here gives an accurate distance
@@ -250,7 +282,7 @@ bool workingset_refault(void *shadow)
inc_zone_state(zone, WORKINGSET_REFAULT);
- if (refault_distance <= zone_page_state(zone, NR_ACTIVE_FILE)) {
+ if (refault_distance <= active_file) {
inc_zone_state(zone, WORKINGSET_ACTIVATE);
return true;
}
@@ -263,7 +295,12 @@ bool workingset_refault(void *shadow)
*/
void workingset_activation(struct page *page)
{
- atomic_long_inc(&page_zone(page)->inactive_age);
+ struct lruvec *lruvec;
+
+ rcu_read_lock();
+ lruvec = mem_cgroup_zone_lruvec(page_zone(page), page_memcg(page));
+ atomic_long_inc(&lruvec->inactive_age);
+ rcu_read_unlock();
}
/*
--
2.7.0