Messages in this thread Patch in this message | | | From | Qi Zheng <> | Subject | [PATCH v3 48/49] mm: shrinker: hold write lock to reparent shrinker nr_deferred | Date | Thu, 27 Jul 2023 16:05:01 +0800 |
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For now, reparent_shrinker_deferred() is the only holder of read lock of shrinker_rwsem. And it already holds the global cgroup_mutex, so it will not be called in parallel.
Therefore, in order to convert shrinker_rwsem to shrinker_mutex later, here we change to hold the write lock of shrinker_rwsem to reparent.
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> --- mm/shrinker.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/shrinker.c b/mm/shrinker.c index fee6f62904fb..a12dede5d21f 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -299,7 +299,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) parent = root_mem_cgroup; /* Prevent from concurrent shrinker_info expand */ - down_read(&shrinker_rwsem); + down_write(&shrinker_rwsem); for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); @@ -312,7 +312,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) } } } - up_read(&shrinker_rwsem); + up_write(&shrinker_rwsem); } #else static int shrinker_memcg_alloc(struct shrinker *shrinker) -- 2.30.2
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