| Message ID | 1608614453-10739-2-git-send-email-alex.shi@linux.alibaba.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2,1/3] mm/memcg: revise the using condition of lock_page_lruvec function series | expand |
Cc: Hui Su and Alexander Duyck as Hugh suggested. 在 2020/12/22 下午1:20, Alex Shi 写道: > 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 Dickin's polished the commit log, Thanks a lot! > > 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> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: cgroups@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memcontrol.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 8d400efc81b9..0af13c4fe4b3 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1356,10 +1356,8 @@ 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); > > @@ -1371,10 +1369,8 @@ 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); > > @@ -1386,10 +1382,8 @@ 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); > >
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8d400efc81b9..0af13c4fe4b3 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1356,10 +1356,8 @@ 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); @@ -1371,10 +1369,8 @@ 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); @@ -1386,10 +1382,8 @@ 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);