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dkim=pass header.d=bytedance-com.20150623.gappssmtp.com header.s=20150623 header.b=MwXJs4sz; spf=pass (imf18.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.215.171 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: C195B20007E0 X-Stat-Signature: oubmas8qdn5s7g8k1nmwq7ykj43qo7x3 X-HE-Tag: 1622108059-342279 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Similar to lruvec lock, we use the same approach to make the lock safe when the LRU pages reparented. Signed-off-by: Muchun Song --- mm/huge_memory.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d8590408abbb..8f0761563d46 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -506,6 +506,8 @@ static struct deferred_split *lock_split_queue(struct page *page) struct deferred_split *queue; struct mem_cgroup *memcg; + rcu_read_lock(); +retry: memcg = page_memcg(compound_head(page)); if (memcg) queue = &memcg->deferred_split_queue; @@ -513,6 +515,17 @@ static struct deferred_split *lock_split_queue(struct page *page) queue = &NODE_DATA(page_to_nid(page))->deferred_split_queue; spin_lock(&queue->split_queue_lock); + if (unlikely(memcg != page_memcg(page))) { + spin_unlock(&queue->split_queue_lock); + goto retry; + } + + /* + * Preemption is disabled in the internal of spin_lock, which can serve + * as RCU read-side critical sections. + */ + rcu_read_unlock(); + return queue; } @@ -522,6 +535,8 @@ static struct deferred_split *lock_split_queue_irqsave(struct page *page, struct deferred_split *queue; struct mem_cgroup *memcg; + rcu_read_lock(); +retry: memcg = page_memcg(compound_head(page)); if (memcg) queue = &memcg->deferred_split_queue; @@ -529,6 +544,14 @@ static struct deferred_split *lock_split_queue_irqsave(struct page *page, queue = &NODE_DATA(page_to_nid(page))->deferred_split_queue; spin_lock_irqsave(&queue->split_queue_lock, *flags); + if (unlikely(memcg != page_memcg(page))) { + spin_unlock_irqrestore(&queue->split_queue_lock, *flags); + goto retry; + } + + /* See the comments in lock_split_queue(). */ + rcu_read_unlock(); + return queue; } #else