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authorMichal Hocko <mhocko@suse.cz>2013-09-12 15:13:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 15:38:00 -0700
commitde57780dc659f95b17ccb649f003278dde0b5b86 (patch)
treed2493cc412c16946f3ead9158a61b26dd1f0c45a /include
parenta5b7c87f92076352dbff2fe0423ec255e1c9a71b (diff)
downloadlinux-linaro-stable-de57780dc659f95b17ccb649f003278dde0b5b86.tar.gz
memcg: enhance memcg iterator to support predicates
The caller of the iterator might know that some nodes or even subtrees should be skipped but there is no way to tell iterators about that so the only choice left is to let iterators to visit each node and do the selection outside of the iterating code. This, however, doesn't scale well with hierarchies with many groups where only few groups are interesting. This patch adds mem_cgroup_iter_cond variant of the iterator with a callback which gets called for every visited node. There are three possible ways how the callback can influence the walk. Either the node is visited, it is skipped but the tree walk continues down the tree or the whole subtree of the current group is skipped. [hughd@google.com: fix memcg-less page reclaim] Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/memcontrol.h49
1 files changed, 43 insertions, 6 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index d8dd6560621b..d4d1f9b0dbba 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -41,6 +41,23 @@ struct mem_cgroup_reclaim_cookie {
unsigned int generation;
};
+enum mem_cgroup_filter_t {
+ VISIT, /* visit current node */
+ SKIP, /* skip the current node and continue traversal */
+ SKIP_TREE, /* skip the whole subtree and continue traversal */
+};
+
+/*
+ * mem_cgroup_filter_t predicate might instruct mem_cgroup_iter_cond how to
+ * iterate through the hierarchy tree. Each tree element is checked by the
+ * predicate before it is returned by the iterator. If a filter returns
+ * SKIP or SKIP_TREE then the iterator code continues traversal (with the
+ * next node down the hierarchy or the next node that doesn't belong under the
+ * memcg's subtree).
+ */
+typedef enum mem_cgroup_filter_t
+(*mem_cgroup_iter_filter)(struct mem_cgroup *memcg, struct mem_cgroup *root);
+
#ifdef CONFIG_MEMCG
/*
* All "charge" functions with gfp_mask should use GFP_KERNEL or
@@ -108,9 +125,18 @@ mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
struct page *oldpage, struct page *newpage, bool migration_ok);
-struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
- struct mem_cgroup *,
- struct mem_cgroup_reclaim_cookie *);
+struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim,
+ mem_cgroup_iter_filter cond);
+
+static inline struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim)
+{
+ return mem_cgroup_iter_cond(root, prev, reclaim, NULL);
+}
+
void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
/*
@@ -180,7 +206,8 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
mem_cgroup_update_page_stat(page, idx, -1);
}
-bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
+enum mem_cgroup_filter_t
+mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
struct mem_cgroup *root);
void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
@@ -295,6 +322,15 @@ static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
struct page *oldpage, struct page *newpage, bool migration_ok)
{
}
+static inline struct mem_cgroup *
+mem_cgroup_iter_cond(struct mem_cgroup *root,
+ struct mem_cgroup *prev,
+ struct mem_cgroup_reclaim_cookie *reclaim,
+ mem_cgroup_iter_filter cond)
+{
+ /* first call must return non-NULL, second return NULL */
+ return (struct mem_cgroup *)(unsigned long)!prev;
+}
static inline struct mem_cgroup *
mem_cgroup_iter(struct mem_cgroup *root,
@@ -358,10 +394,11 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
}
static inline
-bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
+enum mem_cgroup_filter_t
+mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
struct mem_cgroup *root)
{
- return false;
+ return VISIT;
}
static inline void mem_cgroup_split_huge_fixup(struct page *head)