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[2607:7c80:54:e::133]) by mx.google.com with ESMTPS id d3si7603041pgc.461.2019.03.12.08.25.46 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 12 Mar 2019 08:25:46 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) client-ip=2607:7c80:54:e::133; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20170209 header.b=AOvHnDX1; spf=pass (google.com: best guess record for domain of willy@infradead.org designates 2607:7c80:54:e::133 as permitted sender) smtp.mailfrom=willy@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=OAThpFYHfFpJdEy8OwLPNDdww7fmMTYYWyenN4Id6uo=; b=AOvHnDX1lDeBOkejHAgtcES98 maDyEJIbh2t0zujM6b1FKExleWlsQr9ryaTezc2F7EGc7u5iLKFyUKAZt9V0EjkBysvW1PlEps+O0 qGt6i68gN15lovw3xoNxGU2FqsVKU0FpIcGbsogl0lu64m87a7E5ZMT1PIsXOOxBecMp8i5D4/kmB ZThuHfu/oIyz5uRfHh0N3RZRTcRwEjSPvrIEbfIbzRlDWkPmLveIeC9Z4QCSAi6IjN8kE+v9iOU52 x7cXj+QX1JvdxblwYJwnWvHlo6Cdyr6VVLyBsXNYJaFL/+CWtkiBDA/ZyiaVMBOc+JwkWseRE7qzF LVUBGt8hA==; Received: from willy by bombadil.infradead.org with local (Exim 4.90_1 #2 (Red Hat Linux)) id 1h3jHh-0004rb-E5; Tue, 12 Mar 2019 15:25:41 +0000 Date: Tue, 12 Mar 2019 08:25:41 -0700 From: Matthew Wilcox To: Michal Hocko Cc: Suren Baghdasaryan , Sultan Alsawaf , Greg Kroah-Hartman , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Ingo Molnar , Peter Zijlstra , LKML , devel@driverdev.osuosl.org, linux-mm , Tim Murray Subject: Re: [RFC] simple_lmk: Introduce Simple Low Memory Killer for Android Message-ID: <20190312152541.GI19508@bombadil.infradead.org> References: <20190310203403.27915-1-sultan@kerneltoast.com> <20190311174320.GC5721@dhcp22.suse.cz> <20190311175800.GA5522@sultan-box.localdomain> <20190311204626.GA3119@sultan-box.localdomain> <20190312080532.GE5721@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190312080532.GE5721@dhcp22.suse.cz> User-Agent: Mutt/1.9.2 (2017-12-15) 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: On Tue, Mar 12, 2019 at 09:05:32AM +0100, Michal Hocko wrote: > On Mon 11-03-19 15:15:35, Suren Baghdasaryan wrote: > > Yeah, killing speed is a well-known problem which we are considering > > in LMKD. For example the recent LMKD change to assign process being > > killed to a cpuset cgroup containing big cores cuts the kill time > > considerably. This is not ideal and we are thinking about better ways > > to expedite the cleanup process. > > If you design is relies on the speed of killing then it is fundamentally > flawed AFAICT. You cannot assume anything about how quickly a task dies. > It might be blocked in an uninterruptible sleep or performin an > operation which takes some time. Sure, oom_reaper might help here but > still. Many UNINTERRUPTIBLE sleeps can be converted to KILLABLE sleeps. It just needs someone to do the work.