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| 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 /mm/slab.h | |
| parent | mm: vmscan: simplify lruvec_lru_size() (diff) | |
| download | wireguard-linux-867e5e1de14b2b2bde324cdfeec3f3f83eb21424.tar.xz wireguard-linux-867e5e1de14b2b2bde324cdfeec3f3f83eb21424.zip | |
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 'mm/slab.h')
| -rw-r--r-- | mm/slab.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/mm/slab.h b/mm/slab.h index 8b77f973a6ab..7e94700aa78c 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -369,7 +369,7 @@ static __always_inline int memcg_charge_slab(struct page *page, if (ret) goto out; - lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg); + lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page)); mod_lruvec_state(lruvec, cache_vmstat_idx(s), 1 << order); /* transer try_charge() page references to kmem_cache */ @@ -393,7 +393,7 @@ static __always_inline void memcg_uncharge_slab(struct page *page, int order, rcu_read_lock(); memcg = READ_ONCE(s->memcg_params.memcg); if (likely(!mem_cgroup_is_root(memcg))) { - lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg); + lruvec = mem_cgroup_lruvec(memcg, page_pgdat(page)); mod_lruvec_state(lruvec, cache_vmstat_idx(s), -(1 << order)); memcg_kmem_uncharge_memcg(page, order, memcg); } else { |