From: Michal Hocko <mhocko@suse.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
Yang Shi <shy828301@gmail.com>, Wei Xu <weixugc@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Feng Tang <feng.tang@intel.com>
Subject: Re: memcg reclaim demotion wrt. isolation
Date: Wed, 14 Dec 2022 10:49:33 +0100 [thread overview]
Message-ID: <Y5mcLdBioMG+G9WS@dhcp22.suse.cz> (raw)
In-Reply-To: <87o7s6g09b.fsf@yhuang6-desk2.ccr.corp.intel.com>
On Wed 14-12-22 10:57:52, Huang, Ying wrote:
> Michal Hocko <mhocko@suse.com> writes:
[...]
> > This makes sense but I suspect that this wasn't intended also for
> > memcg triggered reclaim. This would mean that a memory pressure in one
> > hierarchy could trigger paging out pages of a different hierarchy if the
> > demotion target is close to full.
>
> It seems that it's unnecessary to wake up kswapd of demotion target node
> in most cases. Because we will try to reclaim on the demotion target
> nodes in the loop of do_try_to_free_pages(). It may be better to loop
> the zonelist in the reverse order. Because the demotion targets are
> usually located at the latter of the zonelist.
Reclaiming from demotion targets first would deal with that as well.
Thanks! Let's establish whether this is something we really need/want
fix first.
--
Michal Hocko
SUSE Labs
prev parent reply other threads:[~2022-12-14 9:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-13 15:41 memcg reclaim demotion wrt. isolation Michal Hocko
2022-12-13 16:14 ` Johannes Weiner
2022-12-14 9:42 ` Michal Hocko
2022-12-14 12:40 ` Johannes Weiner
2022-12-14 15:29 ` Michal Hocko
2022-12-14 17:40 ` Johannes Weiner
2022-12-15 6:17 ` Huang, Ying
2022-12-15 8:22 ` Johannes Weiner
2022-12-16 3:16 ` Huang, Ying
2022-12-13 22:26 ` Dave Hansen
2022-12-14 9:45 ` Michal Hocko
2022-12-14 2:57 ` Huang, Ying
2022-12-14 9:49 ` Michal Hocko [this message]
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