diff options
| author | Kinsey Ho <kinseyho@google.com> | 2024-09-05 02:30:54 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-10 01:39:16 +0200 |
| commit | aa50b501c0529677c27211c79c5b81de60af20a1 (patch) | |
| tree | b25e09d827843ff7f214de3d6f344efa91cef128 | |
| parent | mm: restart if multiple traversals raced (diff) | |
| download | linux-aa50b501c0529677c27211c79c5b81de60af20a1.tar.xz linux-aa50b501c0529677c27211c79c5b81de60af20a1.zip | |
mm: clean up mem_cgroup_iter()
A clean up to make variable names more clear and to improve code
readability.
No functional change.
Link: https://lkml.kernel.org/r/20240905003058.1859929-6-kinseyho@google.com
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Reviewed-by: T.J. Mercier <tjmercier@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/memcontrol.c | 32 |
1 files changed, 12 insertions, 20 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 36cbc7730745..d632650c6a2b 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -987,8 +987,8 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, { struct mem_cgroup_reclaim_iter *iter; struct cgroup_subsys_state *css; - struct mem_cgroup *memcg; - struct mem_cgroup *pos = NULL; + struct mem_cgroup *pos; + struct mem_cgroup *next; if (mem_cgroup_disabled()) return NULL; @@ -998,14 +998,13 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, rcu_read_lock(); restart: - memcg = NULL; + next = NULL; if (reclaim) { int gen; - struct mem_cgroup_per_node *mz; + int nid = reclaim->pgdat->node_id; - mz = root->nodeinfo[reclaim->pgdat->node_id]; - iter = &mz->iter; + iter = &root->nodeinfo[nid]->iter; gen = atomic_read(&iter->generation); /* @@ -1018,29 +1017,22 @@ restart: goto out_unlock; pos = READ_ONCE(iter->position); - } else if (prev) { + } else pos = prev; - } css = pos ? &pos->css : NULL; - for (;;) { - css = css_next_descendant_pre(css, &root->css); - if (!css) { - break; - } - + while ((css = css_next_descendant_pre(css, &root->css))) { /* * Verify the css and acquire a reference. The root * is provided by the caller, so we know it's alive * and kicking, and don't take an extra reference. */ - if (css == &root->css || css_tryget(css)) { + if (css == &root->css || css_tryget(css)) break; - } } - memcg = mem_cgroup_from_css(css); + next = mem_cgroup_from_css(css); if (reclaim) { /* @@ -1048,13 +1040,13 @@ restart: * thread, so check that the value hasn't changed since we read * it to avoid reclaiming from the same cgroup twice. */ - if (cmpxchg(&iter->position, pos, memcg) != pos) { + if (cmpxchg(&iter->position, pos, next) != pos) { if (css && css != &root->css) css_put(css); goto restart; } - if (!memcg) { + if (!next) { atomic_inc(&iter->generation); /* @@ -1073,7 +1065,7 @@ out_unlock: if (prev && prev != root) css_put(&prev->css); - return memcg; + return next; } /** |