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| author | Kinsey Ho <kinseyho@google.com> | 2024-09-05 00:30:50 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-09 16:39:15 -0700 |
| commit | 0e40cf2a8b2c847950e025d5aa594bd545118d26 (patch) | |
| tree | 15ced2cc024c8f0bda14cd2678884f87730a8239 /include/linux | |
| parent | 6e94da943ba3ebd8c603872010ff6efcb682fe9c (diff) | |
| download | linux-0e40cf2a8b2c847950e025d5aa594bd545118d26.tar.gz linux-0e40cf2a8b2c847950e025d5aa594bd545118d26.tar.bz2 linux-0e40cf2a8b2c847950e025d5aa594bd545118d26.zip | |
cgroup: clarify css sibling linkage is protected by cgroup_mutex or RCU
Patch series "Improve mem_cgroup_iter()", v4.
Incremental cgroup iteration is being used again [1]. This patchset
improves the reliability of mem_cgroup_iter(). It also improves
simplicity and code readability.
[1] https://lore.kernel.org/20240514202641.2821494-1-hannes@cmpxchg.org/
This patch (of 5):
Explicitly document that css sibling/descendant linkage is protected by
cgroup_mutex or RCU. Also, document in css_next_descendant_pre() and
similar functions that it isn't necessary to hold a ref on @pos.
The following changes in this patchset rely on this clarification for
simplification in memcg iteration code.
Link: https://lkml.kernel.org/r/20240905003058.1859929-1-kinseyho@google.com
Link: https://lkml.kernel.org/r/20240905003058.1859929-2-kinseyho@google.com
Suggested-by: Yosry Ahmed <yosryahmed@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Kinsey Ho <kinseyho@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
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: Zefan Li <lizefan.x@bytedance.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: T.J. Mercier <tjmercier@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/cgroup-defs.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h index 7fc2d0195f56..ca7e912b8355 100644 --- a/include/linux/cgroup-defs.h +++ b/include/linux/cgroup-defs.h @@ -172,7 +172,11 @@ struct cgroup_subsys_state { /* reference count - access via css_[try]get() and css_put() */ struct percpu_ref refcnt; - /* siblings list anchored at the parent's ->children */ + /* + * siblings list anchored at the parent's ->children + * + * linkage is protected by cgroup_mutex or RCU + */ struct list_head sibling; struct list_head children; |