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From: chenqiwu <qiwuchen55@gmail.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Chris Down <chris@chrisdown.name>,
	akpm@linux-foundation.org, linux-mm@kvack.org,
	chenqiwu <chenqiwu@xiaomi.com>
Subject: Re: [PATCH] mm/vmscan: fix incorrect return type for cgroup_reclaim()
Date: Fri, 20 Mar 2020 10:29:50 +0800	[thread overview]
Message-ID: <20200320022950.GB31830@cqw-OptiPlex-7050> (raw)
In-Reply-To: <20200319173606.GL22433@bombadil.infradead.org>

On Thu, Mar 19, 2020 at 10:36:06AM -0700, Matthew Wilcox wrote:
> On Thu, Mar 19, 2020 at 04:20:25PM +0000, Chris Down wrote:
> 
> I think this is actually the important bit.  For those who build
> their kernels with cgroups disabled, it will save a small number of
> instructions since cgroup_reclaim() will be NULL rather than dereferencing
> sc->target_mem_group.  It'd be nice to have that saving quantified as
> part of the changelog.

I agree.

> 
> > > @@ -2625,7 +2626,7 @@ static inline bool should_continue_reclaim(struct pglist_data *pgdat,
> > > 
> > > static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
> > > {
> > > -	struct mem_cgroup *target_memcg = sc->target_mem_cgroup;
> > > +	struct mem_cgroup *target_memcg = cgroup_reclaim(sc);
> 
> It feels like the name is wrong, doesn't it?  cgroup_reclaim() doesn't
> really scream to me "I return a mem_cgroup pointer".  I can't think of
> a good name, but maybe someone else can.
> 

I can't think of a good name, too. Maybe we just keep it unchanged if
nobody else can.


  reply	other threads:[~2020-03-20  2:29 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-19 15:50 qiwuchen55
2020-03-19 16:07 ` Michal Hocko
2020-03-20  7:34   ` Baoquan He
2020-03-19 16:20 ` Chris Down
2020-03-19 17:36   ` Matthew Wilcox
2020-03-20  2:29     ` chenqiwu [this message]
2020-03-20  7:28     ` Michal Hocko
2020-03-20  2:20   ` chenqiwu

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