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From: Roman Gushchin <guro@fb.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-mm@kvack.org>, Michal Hocko <mhocko@kernel.org>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Shakeel Butt <shakeelb@google.com>,
	<linux-kernel@vger.kernel.org>, <kernel-team@fb.com>,
	Imran Khan <imran.f.khan@oracle.com>
Subject: Re: [PATCH] mm: memcg/slab: optimize objcg stock draining
Date: Wed, 6 Jan 2021 12:04:40 -0800	[thread overview]
Message-ID: <20210106200440.GC1110904@carbon.dhcp.thefacebook.com> (raw)
In-Reply-To: <20210106115044.c4393afa1ad61ef3f8db1d94@linux-foundation.org>

On Wed, Jan 06, 2021 at 11:50:44AM -0800, Andrew Morton wrote:
> On Tue, 5 Jan 2021 20:22:39 -0800 Roman Gushchin <guro@fb.com> wrote:
> 
> > Imran Khan reported a regression in hackbench results caused by the
> > commit f2fe7b09a52b ("mm: memcg/slab: charge individual slab objects
> > instead of pages").
> 
> How large was the regression?

~16% according to Imran's data.

> 
> > --- a/mm/memcontrol.c
> > +++ b/mm/memcontrol.c
> > @@ -3122,9 +3122,7 @@ void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages)
> >  	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
> >  		page_counter_uncharge(&memcg->kmem, nr_pages);
> >  
> > -	page_counter_uncharge(&memcg->memory, nr_pages);
> > -	if (do_memsw_account())
> > -		page_counter_uncharge(&memcg->memsw, nr_pages);
> > +	refill_stock(memcg, nr_pages);
> >  }
> 
> IOW, which kernel version(s) should we be patching?

5.9+

Thanks!

  reply	other threads:[~2021-01-06 20:05 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-06  4:22 [PATCH] mm: memcg/slab: optimize objcg stock draining Roman Gushchin
2021-01-06  6:05 ` Shakeel Butt
2021-01-06 16:42   ` Roman Gushchin
2021-01-06  6:19 ` Imran Khan
2021-01-06 19:50 ` Andrew Morton
2021-01-06 20:04   ` Roman Gushchin [this message]
2021-01-20 16:34 ` Michal Koutný

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