Messages in this thread | | | Date | Wed, 16 Dec 2020 08:35:05 +0100 | From | Michal Hocko <> | Subject | Re: [PATCH] mm/memcontrol: remove the unnecessary rcu_read_[un]lock |
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On Wed 16-12-20 13:52:13, Hui Su wrote: > the rcu_read_lock and rcu_read_unlock is unnecessary in: > lock_page_lruvec() > lock_page_lruvec_irq() > lock_page_lruvec_irqsave()
Please add an explanation why it is unnecessary.
> Signed-off-by: Hui Su <sh_def@163.com> > --- > mm/memcontrol.c | 6 ------ > 1 file changed, 6 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index e3c7ca7dc174..a19f820e8a3f 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1396,10 +1396,8 @@ 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); > > @@ -1411,10 +1409,8 @@ 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); > > @@ -1426,10 +1422,8 @@ 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); > > -- > 2.29.2
-- Michal Hocko SUSE Labs
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