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[209.85.220.65]) by mx.google.com with SMTPS id c14sor10616757ybi.194.2019.01.02.13.46.01 for (Google Transport Security); Wed, 02 Jan 2019 13:46:01 -0800 (PST) Received-SPF: pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=ee3OGe78; spf=pass (google.com: domain of shakeelb@google.com designates 209.85.220.65 as permitted sender) smtp.mailfrom=shakeelb@google.com; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=D0puuOBT2pD/XnAHjsSo/6sVuD3uUPGP+UfDkXMy5oA=; b=ee3OGe781HrG7cNNgDlY6Y1ESKVx3Ll3q10QZPrg1Xjsv1Nd/mY3Er7+cJRoosc5UL wNQARPudiXv0kWIpSJpH2iweIdt02p4syLpsPFNMu/a0k1jVhYRGevnNVbu84KD8vl1g ZCmzt+4y16g9hQ8Ye4yMw2Q97rc9tK5iyvFyP9NSUldVT5Od49FRffiFymyDFGyjSgHq SgP8iNEVAjRld8qaJ9sJ5w6nF2QRasvf5G0MXM2BQW26t/GJ+bLkhI5903g+hIBbZqMc JxEv8JMoLa+Sfe+Gkf2SRtP3V+T4u8BAUhGMmjm2VIbLaGml/VQo9tdZEe04Y4Sd1rtw NQjg== X-Google-Smtp-Source: ALg8bN5KUmK006nxWFp+cGe1e5WwFZFAGFl5TmA+9HHeAe21bPxM8CMyXvoTB+ZS06qvz5c65I7kfuvaZGKXeriVjO4= X-Received: by 2002:a5b:f01:: with SMTP id x1mr41195493ybr.464.1546465560576; Wed, 02 Jan 2019 13:46:00 -0800 (PST) MIME-Version: 1.0 References: <1546459533-36247-1-git-send-email-yang.shi@linux.alibaba.com> <1546459533-36247-3-git-send-email-yang.shi@linux.alibaba.com> In-Reply-To: <1546459533-36247-3-git-send-email-yang.shi@linux.alibaba.com> From: Shakeel Butt Date: Wed, 2 Jan 2019 13:45:49 -0800 Message-ID: Subject: Re: [PATCH 2/3] mm: memcontrol: do not try to do swap when force empty To: Yang Shi Cc: Michal Hocko , Johannes Weiner , Andrew Morton , Linux MM , LKML Content-Type: text/plain; charset="UTF-8" X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Message-ID: <20190102214549.TEIGJyuF9YNBiPGI0MRn8pdf6DG5Wdx8GranPl1Bz98@z> On Wed, Jan 2, 2019 at 12:06 PM Yang Shi wrote: > > The typical usecase of force empty is to try to reclaim as much as > possible memory before offlining a memcg. Since there should be no > attached tasks to offlining memcg, the tasks anonymous pages would have > already been freed or uncharged. Anon pages can come from tmpfs files as well. > Even though anonymous pages get > swapped out, but they still get charged to swap space. So, it sounds > pointless to do swap for force empty. > I understand that force_empty is typically used before rmdir'ing a memcg but it might be used differently by some users. We use this interface to test memory reclaim behavior (anon and file). Anyways, I am not against changing the behavior, we can adapt internally but there might be other users using this interface differently. thanks, Shakeel