diff options
| author | Alex Shi <alex.shi@linux.alibaba.com> | 2021-02-24 23:03:51 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-02-25 00:38:29 +0300 |
| commit | f9b1038ebccad354256cf84749cbc321b5347497 (patch) | |
| tree | 38f668453686927f49584688ed968651c62b4c8f | |
| parent | d7e3aba583e6d13a81932597c5ee8da3c8b6af04 (diff) | |
| download | linux-f9b1038ebccad354256cf84749cbc321b5347497.tar.xz | |
mm/memcg: remove rcu locking for lock_page_lruvec function series
lock_page_lruvec() and its variants used rcu_read_lock() with the
intention of safeguarding against the mem_cgroup being destroyed
concurrently; but so long as they are called under the specified
conditions (as they are), there is no way for the page's mem_cgroup to be
destroyed. Delete the unnecessary rcu_read_lock() and _unlock().
Hugh Dickins polished the commit log. Thanks a lot!
Link: https://lkml.kernel.org/r/1608614453-10739-2-git-send-email-alex.shi@linux.alibaba.com
Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/memcontrol.c | 6 |
1 files changed, 0 insertions, 6 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 2b13b2cf5dcb..5435b370c929 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1357,10 +1357,8 @@ struct lruvec *lock_page_lruvec(struct page *page) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock(&lruvec->lru_lock); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); @@ -1372,10 +1370,8 @@ struct lruvec *lock_page_lruvec_irq(struct page *page) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock_irq(&lruvec->lru_lock); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); @@ -1387,10 +1383,8 @@ struct lruvec *lock_page_lruvec_irqsave(struct page *page, unsigned long *flags) struct lruvec *lruvec; struct pglist_data *pgdat = page_pgdat(page); - rcu_read_lock(); lruvec = mem_cgroup_page_lruvec(page, pgdat); spin_lock_irqsave(&lruvec->lru_lock, *flags); - rcu_read_unlock(); lruvec_memcg_debug(lruvec, page); |