From: Michal Hocko <mhocko@suse.com>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: hannes@cmpxchg.org, vdavydov.dev@gmail.com,
akpm@linux-foundation.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [PATCH 3/3] mm/memcg: add next_mz back if not reclaimed yet
Date: Thu, 10 Mar 2022 09:53:59 +0100 [thread overview]
Message-ID: <Yim8p0C4CxC6SskI@dhcp22.suse.cz> (raw)
In-Reply-To: <20220310011350.2b6fxa66it5nugcy@master>
On Thu 10-03-22 01:13:50, Wei Yang wrote:
> On Wed, Mar 09, 2022 at 02:48:45PM +0100, Michal Hocko wrote:
> >[Cc Tim - the patch is http://lkml.kernel.org/r/20220308012047.26638-3-richard.weiyang@gmail.com]
> >
> >On Wed 09-03-22 00:46:20, Wei Yang wrote:
> >> On Tue, Mar 08, 2022 at 09:17:58AM +0100, Michal Hocko wrote:
> >> >On Tue 08-03-22 01:20:47, Wei Yang wrote:
> >> >> next_mz is removed from rb_tree, let's add it back if no reclaim has
> >> >> been tried.
> >> >
> >> >Could you elaborate more why we need/want this?
> >> >
> >>
> >> Per my understanding, we add back the right most node even reclaim makes no
> >> progress, so it is reasonable to add back a node if we didn't get a chance to
> >> do reclaim on it.
> >
> >Your patch sounded familiar and I can remember now. The same fix has
> >been posted by Tim last year
> >https://lore.kernel.org/linux-mm/8d35206601ccf0e1fe021d24405b2a0c2f4e052f.1613584277.git.tim.c.chen@linux.intel.com/
> >It was posted with other changes to the soft limit code which I didn't
> >like but I have acked this particular one. Not sure what has happened
> >with it afterwards.
>
> Because of this ?
> 4f09feb8bf: vm-scalability.throughput -4.3% regression
> https://lore.kernel.org/linux-mm/20210302062521.GB23892@xsang-OptiPlex-9020/
That was a regression for a different patch in the series AFAICS:
: FYI, we noticed a -4.3% regression of vm-scalability.throughput due to commit:
:
: commit: 4f09feb8bf083be3834080ddf3782aee12a7c3f7 ("mm: Force update of mem cgroup soft limit tree on usage excess")
That patch has played with how often memcg_check_events is called and
that can lead to a visible performance difference.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2022-03-10 8:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-08 1:20 [PATCH 1/3] mm/memcg: mz already removed from rb_tree in mem_cgroup_largest_soft_limit_node() Wei Yang
2022-03-08 1:20 ` [PATCH 2/3] mm/memcg: __mem_cgroup_remove_exceeded could handle a !on-tree mz properly Wei Yang
2022-03-08 1:20 ` [PATCH 3/3] mm/memcg: add next_mz back if not reclaimed yet Wei Yang
2022-03-08 8:17 ` Michal Hocko
2022-03-09 0:46 ` Wei Yang
2022-03-09 13:48 ` Michal Hocko
2022-03-10 1:13 ` Wei Yang
2022-03-10 8:53 ` Michal Hocko [this message]
2022-03-10 23:57 ` Wei Yang
2022-03-10 8:59 ` Michal Hocko
2022-03-10 23:55 ` Wei Yang
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