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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 /fs/xfs/xfs_qm.c
parent10c1045f28e86ac90589a188f0be2d7a4347efdf (diff)
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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>
Diffstat (limited to 'fs/xfs/xfs_qm.c')
-rw-r--r--fs/xfs/xfs_qm.c7
1 files changed, 3 insertions, 4 deletions
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);
}
/*