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 <[email protected]> > Acked-by: Hugh Dickins <[email protected]> > Cc: Hugh Dickins <[email protected]> > Cc: Johannes Weiner <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: Vladimir Davydov <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] > --- > 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); > >
