From: Johannes Weiner <hannes@cmpxchg.org>
To: Roman Gushchin <guroan@gmail.com>
Cc: linux-mm@kvack.org, kernel-team@fb.com,
linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Rik van Riel <riel@surriel.com>, Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <guro@fb.com>
Subject: Re: [PATCH v2 5/6] mm: flush memcg percpu stats and events before releasing
Date: Wed, 13 Mar 2019 12:00:17 -0400 [thread overview]
Message-ID: <20190313160017.GA31891@cmpxchg.org> (raw)
In-Reply-To: <20190312223404.28665-6-guro@fb.com>
On Tue, Mar 12, 2019 at 03:34:02PM -0700, Roman Gushchin wrote:
> Flush percpu stats and events data to corresponding before releasing
> percpu memory.
>
> Although per-cpu stats are never exactly precise, dropping them on
> floor regularly may lead to an accumulation of an error. So, it's
> safer to flush them before releasing.
>
> To minimize the number of atomic updates, let's sum all stats/events
> on all cpus locally, and then make a single update per entry.
>
> Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Do you mind merging 6/6 into this one? That would make it easier to
verify that the code added in this patch and the code removed in 6/6
are indeed functionally equivalent.
next prev parent reply other threads:[~2019-03-13 16:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-12 22:33 [PATCH v2 0/6] mm: reduce the memory footprint of dying memory cgroups Roman Gushchin
2019-03-12 22:33 ` [PATCH v2 1/6] mm: prepare to premature release of memcg->vmstats_percpu Roman Gushchin
2019-03-12 22:33 ` [PATCH v2 2/6] mm: prepare to premature release of per-node lruvec_stat_cpu Roman Gushchin
2019-03-12 22:34 ` [PATCH v2 3/6] mm: release memcg percpu data prematurely Roman Gushchin
2019-03-12 22:34 ` [PATCH v2 4/6] mm: release per-node " Roman Gushchin
2019-03-12 22:34 ` [PATCH v2 5/6] mm: flush memcg percpu stats and events before releasing Roman Gushchin
2019-03-13 16:00 ` Johannes Weiner [this message]
2019-03-13 18:23 ` Roman Gushchin
2019-03-12 22:34 ` [PATCH 5/5] mm: spill " Roman Gushchin
2019-03-12 22:34 ` [PATCH v2 6/6] mm: refactor memcg_hotplug_cpu_dead() to use memcg_flush_offline_percpu() Roman Gushchin
2019-03-13 16:07 ` Johannes Weiner
2019-03-13 18:23 ` Roman Gushchin
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