diff options
author | Johannes Weiner <hannes@cmpxchg.org> | 2019-11-30 17:55:34 -0800 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-12-01 12:59:06 -0800 |
commit | 867e5e1de14b2b2bde324cdfeec3f3f83eb21424 (patch) | |
tree | 22a8f8e2142314de860983c95d89fbe86b39cf1a /include/linux/mmzone.h | |
parent | de3b01506ea494b46aab05dc143b69adbf2aaa9d (diff) |
mm: clean up and clarify lruvec lookup procedure
There is a per-memcg lruvec and a NUMA node lruvec. Which one is being
used is somewhat confusing right now, and it's easy to make mistakes -
especially when it comes to global reclaim.
How it works: when memory cgroups are enabled, we always use the
root_mem_cgroup's per-node lruvecs. When memory cgroups are not compiled
in or disabled at runtime, we use pgdat->lruvec.
Document that in a comment.
Due to the way the reclaim code is generalized, all lookups use the
mem_cgroup_lruvec() helper function, and nobody should have to find the
right lruvec manually right now. But to avoid future mistakes, rename the
pgdat->lruvec member to pgdat->__lruvec and delete the convenience wrapper
that suggests it's a commonly accessed member.
While in this area, swap the mem_cgroup_lruvec() argument order. The name
suggests a memcg operation, yet it takes a pgdat first and a memcg second.
I have to double take every time I call this. Fix that.
Link: http://lkml.kernel.org/r/20191022144803.302233-3-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mmzone.h')
-rw-r--r-- | include/linux/mmzone.h | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index c7fb21f19edd..cc8232a100bd 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -777,7 +777,13 @@ typedef struct pglist_data { #endif /* Fields commonly accessed by the page reclaim scanner */ - struct lruvec lruvec; + + /* + * NOTE: THIS IS UNUSED IF MEMCG IS ENABLED. + * + * Use mem_cgroup_lruvec() to look up lruvecs. + */ + struct lruvec __lruvec; unsigned long flags; @@ -800,11 +806,6 @@ typedef struct pglist_data { #define node_start_pfn(nid) (NODE_DATA(nid)->node_start_pfn) #define node_end_pfn(nid) pgdat_end_pfn(NODE_DATA(nid)) -static inline struct lruvec *node_lruvec(struct pglist_data *pgdat) -{ - return &pgdat->lruvec; -} - static inline unsigned long pgdat_end_pfn(pg_data_t *pgdat) { return pgdat->node_start_pfn + pgdat->node_spanned_pages; @@ -842,7 +843,7 @@ static inline struct pglist_data *lruvec_pgdat(struct lruvec *lruvec) #ifdef CONFIG_MEMCG return lruvec->pgdat; #else - return container_of(lruvec, struct pglist_data, lruvec); + return container_of(lruvec, struct pglist_data, __lruvec); #endif } |