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authorVladimir Davydov <vdavydov@parallels.com>2015-02-12 14:58:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-12 18:54:08 -0800
commit503c358cf1925853195ee39ec437e51138bbb7df (patch)
tree14aebe291975ec4353f21068990ebfec503ed63f
parent10c1045f28e86ac90589a188f0be2d7a4347efdf (diff)
list_lru: introduce list_lru_shrink_{count,walk}
Kmem accounting of memcg is unusable now, because it lacks slab shrinker support. That means when we hit the limit we will get ENOMEM w/o any chance to recover. What we should do then is to call shrink_slab, which would reclaim old inode/dentry caches from this cgroup. This is what this patch set is intended to do. Basically, it does two things. First, it introduces the notion of per-memcg slab shrinker. A shrinker that wants to reclaim objects per cgroup should mark itself as SHRINKER_MEMCG_AWARE. Then it will be passed the memory cgroup to scan from in shrink_control->memcg. For such shrinkers shrink_slab iterates over the whole cgroup subtree under the target cgroup and calls the shrinker for each kmem-active memory cgroup. Secondly, this patch set makes the list_lru structure per-memcg. It's done transparently to list_lru users - everything they have to do is to tell list_lru_init that they want memcg-aware list_lru. Then the list_lru will automatically distribute objects among per-memcg lists basing on which cgroup the object is accounted to. This way to make FS shrinkers (icache, dcache) memcg-aware we only need to make them use memcg-aware list_lru, and this is what this patch set does. As before, this patch set only enables per-memcg kmem reclaim when the pressure goes from memory.limit, not from memory.kmem.limit. Handling memory.kmem.limit is going to be tricky due to GFP_NOFS allocations, and it is still unclear whether we will have this knob in the unified hierarchy. This patch (of 9): NUMA aware slab shrinkers use the list_lru structure to distribute objects coming from different NUMA nodes to different lists. Whenever such a shrinker needs to count or scan objects from a particular node, it issues commands like this: count = list_lru_count_node(lru, sc->nid); freed = list_lru_walk_node(lru, sc->nid, isolate_func, isolate_arg, &sc->nr_to_scan); where sc is an instance of the shrink_control structure passed to it from vmscan. To simplify this, let's add special list_lru functions to be used by shrinkers, list_lru_shrink_count() and list_lru_shrink_walk(), which consolidate the nid and nr_to_scan arguments in the shrink_control structure. This will also allow us to avoid patching shrinkers that use list_lru when we make shrink_slab() per-memcg - all we will have to do is extend the shrink_control structure to include the target memcg and make list_lru_shrink_{count,walk} handle this appropriately. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Suggested-by: Dave Chinner <david@fromorbit.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Greg Thelen <gthelen@google.com> Cc: Glauber Costa <glommer@gmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Lameter <cl@linux.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/dcache.c14
-rw-r--r--fs/gfs2/quota.c6
-rw-r--r--fs/inode.c7
-rw-r--r--fs/internal.h7
-rw-r--r--fs/super.c24
-rw-r--r--fs/xfs/xfs_buf.c7
-rw-r--r--fs/xfs/xfs_qm.c7
-rw-r--r--include/linux/list_lru.h16
-rw-r--r--mm/workingset.c6
9 files changed, 51 insertions, 43 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index e368d4f412f9..56c5da89f58a 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -930,24 +930,22 @@ dentry_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg)
/**
* prune_dcache_sb - shrink the dcache
* @sb: superblock
- * @nr_to_scan : number of entries to try to free
- * @nid: which node to scan for freeable entities
+ * @sc: shrink control, passed to list_lru_shrink_walk()
*
- * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is
- * done when we need more memory an called from the superblock shrinker
+ * Attempt to shrink the superblock dcache LRU by @sc->nr_to_scan entries. This
+ * is done when we need more memory and called from the superblock shrinker
* function.
*
* This function may fail to free any resources if all the dentries are in
* use.
*/
-long prune_dcache_sb(struct super_block *sb, unsigned long nr_to_scan,
- int nid)
+long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc)
{
LIST_HEAD(dispose);
long freed;
- freed = list_lru_walk_node(&sb->s_dentry_lru, nid, dentry_lru_isolate,
- &dispose, &nr_to_scan);
+ freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc,
+ dentry_lru_isolate, &dispose);
shrink_dentry_list(&dispose);
return freed;
}
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index 3e193cb36996..c15d6b216d0b 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -171,8 +171,8 @@ static unsigned long gfs2_qd_shrink_scan(struct shrinker *shrink,
if (!(sc->gfp_mask & __GFP_FS))
return SHRINK_STOP;
- freed = list_lru_walk_node(&gfs2_qd_lru, sc->nid, gfs2_qd_isolate,
- &dispose, &sc->nr_to_scan);
+ freed = list_lru_shrink_walk(&gfs2_qd_lru, sc,
+ gfs2_qd_isolate, &dispose);
gfs2_qd_dispose(&dispose);
@@ -182,7 +182,7 @@ static unsigned long gfs2_qd_shrink_scan(struct shrinker *shrink,
static unsigned long gfs2_qd_shrink_count(struct shrinker *shrink,
struct shrink_control *sc)
{
- return vfs_pressure_ratio(list_lru_count_node(&gfs2_qd_lru, sc->nid));
+ return vfs_pressure_ratio(list_lru_shrink_count(&gfs2_qd_lru, sc));
}
struct shrinker gfs2_qd_shrinker = {
diff --git a/fs/inode.c b/fs/inode.c
index 3a53b1da3fb8..524a32c2b0c6 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -751,14 +751,13 @@ inode_lru_isolate(struct list_head *item, spinlock_t *lru_lock, void *arg)
* to trim from the LRU. Inodes to be freed are moved to a temporary list and
* then are freed outside inode_lock by dispose_list().
*/
-long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
- int nid)
+long prune_icache_sb(struct super_block *sb, struct shrink_control *sc)
{
LIST_HEAD(freeable);
long freed;
- freed = list_lru_walk_node(&sb->s_inode_lru, nid, inode_lru_isolate,
- &freeable, &nr_to_scan);
+ freed = list_lru_shrink_walk(&sb->s_inode_lru, sc,
+ inode_lru_isolate, &freeable);
dispose_list(&freeable);
return freed;
}
diff --git a/fs/internal.h b/fs/internal.h
index e9a61fe67575..d92c346a793d 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -14,6 +14,7 @@ struct file_system_type;
struct linux_binprm;
struct path;
struct mount;
+struct shrink_control;
/*
* block_dev.c
@@ -111,8 +112,7 @@ extern int open_check_o_direct(struct file *f);
* inode.c
*/
extern spinlock_t inode_sb_list_lock;
-extern long prune_icache_sb(struct super_block *sb, unsigned long nr_to_scan,
- int nid);
+extern long prune_icache_sb(struct super_block *sb, struct shrink_control *sc);
extern void inode_add_lru(struct inode *inode);
/*
@@ -129,8 +129,7 @@ extern int invalidate_inodes(struct super_block *, bool);
*/
extern struct dentry *__d_alloc(struct super_block *, const struct qstr *);
extern int d_set_mounted(struct dentry *dentry);
-extern long prune_dcache_sb(struct super_block *sb, unsigned long nr_to_scan,
- int nid);
+extern long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc);
/*
* read_write.c
diff --git a/fs/super.c b/fs/super.c
index eae088f6aaae..4554ac257647 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -77,8 +77,8 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
if (sb->s_op->nr_cached_objects)
fs_objects = sb->s_op->nr_cached_objects(sb, sc->nid);
- inodes = list_lru_count_node(&sb->s_inode_lru, sc->nid);
- dentries = list_lru_count_node(&sb->s_dentry_lru, sc->nid);
+ inodes = list_lru_shrink_count(&sb->s_inode_lru, sc);
+ dentries = list_lru_shrink_count(&sb->s_dentry_lru, sc);
total_objects = dentries + inodes + fs_objects + 1;
if (!total_objects)
total_objects = 1;
@@ -86,20 +86,20 @@ static unsigned long super_cache_scan(struct shrinker *shrink,
/* proportion the scan between the caches */
dentries = mult_frac(sc->nr_to_scan, dentries, total_objects);
inodes = mult_frac(sc->nr_to_scan, inodes, total_objects);
+ fs_objects = mult_frac(sc->nr_to_scan, fs_objects, total_objects);
/*
* prune the dcache first as the icache is pinned by it, then
* prune the icache, followed by the filesystem specific caches
*/
- freed = prune_dcache_sb(sb, dentries, sc->nid);
- freed += prune_icache_sb(sb, inodes, sc->nid);
+ sc->nr_to_scan = dentries;
+ freed = prune_dcache_sb(sb, sc);
+ sc->nr_to_scan = inodes;
+ freed += prune_icache_sb(sb, sc);
- if (fs_objects) {
- fs_objects = mult_frac(sc->nr_to_scan, fs_objects,
- total_objects);
+ if (fs_objects)
freed += sb->s_op->free_cached_objects(sb, fs_objects,
sc->nid);
- }
drop_super(sb);
return freed;
@@ -118,17 +118,15 @@ static unsigned long super_cache_count(struct shrinker *shrink,
* scalability bottleneck. The counts could get updated
* between super_cache_count and super_cache_scan anyway.
* Call to super_cache_count with shrinker_rwsem held
- * ensures the safety of call to list_lru_count_node() and
+ * ensures the safety of call to list_lru_shrink_count() and
* s_op->nr_cached_objects().
*/
if (sb->s_op && sb->s_op->nr_cached_objects)
total_objects = sb->s_op->nr_cached_objects(sb,
sc->nid);
- total_objects += list_lru_count_node(&sb->s_dentry_lru,
- sc->nid);
- total_objects += list_lru_count_node(&sb->s_inode_lru,
- sc->nid);
+ total_objects += list_lru_shrink_count(&sb->s_dentry_lru, sc);
+ total_objects += list_lru_shrink_count(&sb->s_inode_lru, sc);
total_objects = vfs_pressure_ratio(total_objects);
return total_objects;
diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index bb502a391792..15c9d224c721 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1583,10 +1583,9 @@ xfs_buftarg_shrink_scan(
struct xfs_buftarg, bt_shrinker);
LIST_HEAD(dispose);
unsigned long freed;
- unsigned long nr_to_scan = sc->nr_to_scan;
- freed = list_lru_walk_node(&btp->bt_lru, sc->nid, xfs_buftarg_isolate,
- &dispose, &nr_to_scan);
+ freed = list_lru_shrink_walk(&btp->bt_lru, sc,
+ xfs_buftarg_isolate, &dispose);
while (!list_empty(&dispose)) {
struct xfs_buf *bp;
@@ -1605,7 +1604,7 @@ xfs_buftarg_shrink_count(
{
struct xfs_buftarg *btp = container_of(shrink,
struct xfs_buftarg, bt_shrinker);
- return list_lru_count_node(&btp->bt_lru, sc->nid);
+ return list_lru_shrink_count(&btp->bt_lru, sc);
}
void
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index 3e8186279541..4f4b1274e144 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -523,7 +523,6 @@ xfs_qm_shrink_scan(
struct xfs_qm_isolate isol;
unsigned long freed;
int error;
- unsigned long nr_to_scan = sc->nr_to_scan;
if ((sc->gfp_mask & (__GFP_FS|__GFP_WAIT)) != (__GFP_FS|__GFP_WAIT))
return 0;
@@ -531,8 +530,8 @@ xfs_qm_shrink_scan(
INIT_LIST_HEAD(&isol.buffers);
INIT_LIST_HEAD(&isol.dispose);
- freed = list_lru_walk_node(&qi->qi_lru, sc->nid, xfs_qm_dquot_isolate, &isol,
- &nr_to_scan);
+ freed = list_lru_shrink_walk(&qi->qi_lru, sc,
+ xfs_qm_dquot_isolate, &isol);
error = xfs_buf_delwri_submit(&isol.buffers);
if (error)
@@ -557,7 +556,7 @@ xfs_qm_shrink_count(
struct xfs_quotainfo *qi = container_of(shrink,
struct xfs_quotainfo, qi_shrinker);
- return list_lru_count_node(&qi->qi_lru, sc->nid);
+ return list_lru_shrink_count(&qi->qi_lru, sc);
}
/*
diff --git a/include/linux/list_lru.h b/include/linux/list_lru.h
index f3434533fbf8..f500a2e39b13 100644
--- a/include/linux/list_lru.h
+++ b/include/linux/list_lru.h
@@ -9,6 +9,7 @@
#include <linux/list.h>
#include <linux/nodemask.h>
+#include <linux/shrinker.h>
/* list_lru_walk_cb has to always return one of those */
enum lru_status {
@@ -81,6 +82,13 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item);
* Callers that want such a guarantee need to provide an outer lock.
*/
unsigned long list_lru_count_node(struct list_lru *lru, int nid);
+
+static inline unsigned long list_lru_shrink_count(struct list_lru *lru,
+ struct shrink_control *sc)
+{
+ return list_lru_count_node(lru, sc->nid);
+}
+
static inline unsigned long list_lru_count(struct list_lru *lru)
{
long count = 0;
@@ -120,6 +128,14 @@ unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
unsigned long *nr_to_walk);
static inline unsigned long
+list_lru_shrink_walk(struct list_lru *lru, struct shrink_control *sc,
+ list_lru_walk_cb isolate, void *cb_arg)
+{
+ return list_lru_walk_node(lru, sc->nid, isolate, cb_arg,
+ &sc->nr_to_scan);
+}
+
+static inline unsigned long
list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate,
void *cb_arg, unsigned long nr_to_walk)
{
diff --git a/mm/workingset.c b/mm/workingset.c
index f7216fa7da27..d4fa7fb10a52 100644
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -275,7 +275,7 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker,
/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
local_irq_disable();
- shadow_nodes = list_lru_count_node(&workingset_shadow_nodes, sc->nid);
+ shadow_nodes = list_lru_shrink_count(&workingset_shadow_nodes, sc);
local_irq_enable();
pages = node_present_pages(sc->nid);
@@ -376,8 +376,8 @@ static unsigned long scan_shadow_nodes(struct shrinker *shrinker,
/* list_lru lock nests inside IRQ-safe mapping->tree_lock */
local_irq_disable();
- ret = list_lru_walk_node(&workingset_shadow_nodes, sc->nid,
- shadow_lru_isolate, NULL, &sc->nr_to_scan);
+ ret = list_lru_shrink_walk(&workingset_shadow_nodes, sc,
+ shadow_lru_isolate, NULL);
local_irq_enable();
return ret;
}