From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: [PATCH mm v2 0/3] memcg: Slow down swap allocation as the available space gets depleted Date: Mon, 11 May 2020 15:55:13 -0700 Message-ID: <20200511225516.2431921-1-kuba@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1589237730; bh=pxjZnopLEhvVuE+hwn+nFyI+Zvw/0BY6mIaM+QZzV7A=; h=From:To:Cc:Subject:Date:From; b=DBRJCAly+tHOgZNaQm1yXJo14p3rpfNMkFGOf/JTiwFC8KbCSIDuK+9NMQxg1l1db 4n9EbIX9vjTGND0oaWj7Dv3rRevFAGRUoKVbP/3+fdsPCYOT3Qpf+I4c6kW1Zw3wYi 3uWV3g5tnzxSHDPldQgRgoZeKEb2DI88HJJ0u/kk= Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" To: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, chris-6Bi1550iOqEnzZ6mRAm98g@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shakeelb-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Jakub Kicinski Tejun describes the problem as follows: When swap runs out, there's an abrupt change in system behavior - the anonymous memory suddenly becomes unmanageable which readily breaks any sort of memory isolation and can bring down the whole system. To avoid that, oomd [1] monitors free swap space and triggers kills when it drops below the specific threshold (e.g. 15%). While this works, it's far from ideal: - Depending on IO performance and total swap size, a given headroom might not be enough or too much. - oomd has to monitor swap depletion in addition to the usual pressure metrics and it currently doesn't consider memory.swap.max. Solve this by adapting parts of the approach that memory.high uses - slow down allocation as the resource gets depleted turning the depletion behavior from abrupt cliff one to gradual degradation observable through memory pressure metric. [1] https://github.com/facebookincubator/oomd v1: https://lore.kernel.org/linux-mm/20200417010617.927266-1-kuba-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org/ Jakub Kicinski (3): mm: prepare for swap over-high accounting and penalty calculation mm: move penalty delay clamping out of calculate_high_delay() mm: automatically penalize tasks with high swap use Documentation/admin-guide/cgroup-v2.rst | 16 +++ include/linux/memcontrol.h | 4 + mm/memcontrol.c | 166 ++++++++++++++++++------ 3 files changed, 147 insertions(+), 39 deletions(-) -- 2.25.4