From: Johannes Weiner <hannes@cmpxchg.org>
To: Hillf Danton <dhillf@gmail.com>
Cc: linux-mm@kvack.org, Michal Hocko <mhocko@suse.cz>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Ying Han <yinghan@google.com>, Hugh Dickins <hughd@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: vmscan: ensure reclaiming pages on the lru lists of zone
Date: Mon, 23 Jan 2012 12:20:22 +0100 [thread overview]
Message-ID: <20120123112022.GB1707@cmpxchg.org> (raw)
In-Reply-To: <CAJd=RBBqp3bMGwFc14BJ7+=KsfO0gLnrnXwbRdLDYOJDdvbptA@mail.gmail.com>
On Mon, Jan 23, 2012 at 12:47:34AM +0800, Hillf Danton wrote:
> Hi all
>
> For easy review, it is re-prepared based on 3.3-rc1.
>
> Thanks
> Hillf
>
> ===cut please===
> From: Hillf Danton <dhillf@gmail.com>
> Subject: [PATCH] mm: vmscan: ensure reclaiming pages on the lru lists of zone
>
> While iterating over memory cgroup hierarchy, pages are reclaimed from each
> mem cgroup, and reclaim terminates after a full round-trip. It is possible
> that no pages on the lru lists of given zone are reclaimed, as termination
> is checked after the reclaiming function.
>
> Mem cgroup iteration is rearranged a bit to make sure that pages are reclaimed
> from both mem cgroups and zone.
It's not only possible, it's guaranteed: with the memory controller
enabled, the global per-zone lru lists are empty.
Pages used to be linked on the global per-zone AND the memcg per-zone
lru lists. Nowadays, they only sit on the memcg per-zone lists, which
is why global reclaim does a hierarchy walk.
The global per-zone lists are just an artifact for when the memory
controller is not available. The plan is to make root_mem_cgroup
available at all times, even without the memory controller.
So I'm afraid your patch only adds a round of scanning a known-to-be
empty lruvec. NAK.
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next prev parent reply other threads:[~2012-01-23 11:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-22 3:08 Hillf Danton
2012-01-22 16:47 ` Hillf Danton
2012-01-23 11:20 ` Johannes Weiner [this message]
2012-01-23 11:53 ` Hillf Danton
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