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| author | Davidlohr Bueso <dave@stgolabs.net> | 2017-09-09 01:15:21 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-09 03:26:49 +0200 |
| commit | fa90b2fd300f38cc7b3e416974116c83f3953465 (patch) | |
| tree | d21f304639c4de0e67a88086fd0f988e41567250 /mm/memcontrol.c | |
| parent | fs/epoll: use faster rb_first_cached() (diff) | |
| download | linux-fa90b2fd300f38cc7b3e416974116c83f3953465.tar.xz linux-fa90b2fd300f38cc7b3e416974116c83f3953465.zip | |
mem/memcg: cache rightmost node
Such that we can optimize __mem_cgroup_largest_soft_limit_node(). The
only overhead is the extra footprint for the cached pointer, but this
should not be an issue for mem_cgroup_tree_per_node.
[dave@stgolabs.net: brain fart #2]
Link: http://lkml.kernel.org/r/20170731160114.GE21328@linux-80c1.suse
Link: http://lkml.kernel.org/r/20170719014603.19029-17-dave@stgolabs.net
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 23 |
1 files changed, 18 insertions, 5 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ca83f3854e4f..15af3da5af02 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -119,6 +119,7 @@ static const char *const mem_cgroup_lru_names[] = { struct mem_cgroup_tree_per_node { struct rb_root rb_root; + struct rb_node *rb_rightmost; spinlock_t lock; }; @@ -386,6 +387,7 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, struct rb_node **p = &mctz->rb_root.rb_node; struct rb_node *parent = NULL; struct mem_cgroup_per_node *mz_node; + bool rightmost = true; if (mz->on_tree) return; @@ -397,8 +399,11 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, parent = *p; mz_node = rb_entry(parent, struct mem_cgroup_per_node, tree_node); - if (mz->usage_in_excess < mz_node->usage_in_excess) + if (mz->usage_in_excess < mz_node->usage_in_excess) { p = &(*p)->rb_left; + rightmost = false; + } + /* * We can't avoid mem cgroups that are over their soft * limit by the same amount @@ -406,6 +411,10 @@ static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz, else if (mz->usage_in_excess >= mz_node->usage_in_excess) p = &(*p)->rb_right; } + + if (rightmost) + mctz->rb_rightmost = &mz->tree_node; + rb_link_node(&mz->tree_node, parent, p); rb_insert_color(&mz->tree_node, &mctz->rb_root); mz->on_tree = true; @@ -416,6 +425,10 @@ static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz, { if (!mz->on_tree) return; + + if (&mz->tree_node == mctz->rb_rightmost) + mctz->rb_rightmost = rb_prev(&mz->tree_node); + rb_erase(&mz->tree_node, &mctz->rb_root); mz->on_tree = false; } @@ -496,16 +509,15 @@ static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) static struct mem_cgroup_per_node * __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz) { - struct rb_node *rightmost = NULL; struct mem_cgroup_per_node *mz; retry: mz = NULL; - rightmost = rb_last(&mctz->rb_root); - if (!rightmost) + if (!mctz->rb_rightmost) goto done; /* Nothing to reclaim from */ - mz = rb_entry(rightmost, struct mem_cgroup_per_node, tree_node); + mz = rb_entry(mctz->rb_rightmost, + struct mem_cgroup_per_node, tree_node); /* * Remove the node now but someone else can add it back, * we will to add it back at the end of reclaim to its correct @@ -5945,6 +5957,7 @@ static int __init mem_cgroup_init(void) node_online(node) ? node : NUMA_NO_NODE); rtpn->rb_root = RB_ROOT; + rtpn->rb_rightmost = NULL; spin_lock_init(&rtpn->lock); soft_limit_tree.rb_tree_per_node[node] = rtpn; } |