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mm: clean up mem_cgroup_iter()

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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>
This commit is contained in:
Kinsey Ho 2024-09-05 00:30:54 +00:00 committed by Andrew Morton
parent ec0db74b4b
commit aa50b501c0
1 changed files with 12 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

32
mm/memcontrol.c
View File

@ -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 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
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 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
* 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 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
if (prev && prev != root)
css_put(&prev->css);
return memcg;
return next;
}
/**