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[209.85.220.41]) by mx.google.com with SMTPS id y3sor2133661wmj.10.2019.03.12.10.15.52 for (Google Transport Security); Tue, 12 Mar 2019 10:15:53 -0700 (PDT) Received-SPF: pass (google.com: domain of surenb@google.com designates 209.85.220.41 as permitted sender) client-ip=209.85.220.41; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=eICtM3WJ; spf=pass (google.com: domain of surenb@google.com designates 209.85.220.41 as permitted sender) smtp.mailfrom=surenb@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=JJNmxFq4kvtgDMxGW5EQZmwTBHXCE8cD8UO0j6EqecE=; b=eICtM3WJdg7Bq7C7keVDYg0CrinSY8xGGeQG45rEmu59uiZfjFMczd9uA/UYhoAK+g hCH2sfdCvx95nRGUSuHYhXxnYObCMQL27F3dvIFV/nD0pkzS+RWsuLvO20H3uohxUK8Q bFWGc02dYBQDpx9KIr9IkMTpmmOLw6OjlJlPjDrBDeBbHlAJFaklVRj5VOu0U31Btj3D Y2PvQxG1UvzKcsj7by517lkcVQ00sM0No4sycN/PgwxHIT9WthtTO4uSpYByiS94nf9g UJ6r3xqwjS105/10FTzY8I8djkMo+4TPDnzH9B4ZzIGH0kaWVK0ouPit1AgkSDsEVjT0 4K0g== X-Google-Smtp-Source: APXvYqx87Bwal2xirLDgWzJL461s60oU++NHtJORE9GT9nlzsH1PR8HvbGpV44aPviSqK/l38j0DtUaUXf28zAVP9qA= X-Received: by 2002:a05:600c:2115:: with SMTP id u21mr3406355wml.70.1552410952458; Tue, 12 Mar 2019 10:15:52 -0700 (PDT) MIME-Version: 1.0 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> <20190312163741.GA2762@sultan-box.localdomain> <20190312165805.GF5721@dhcp22.suse.cz> In-Reply-To: <20190312165805.GF5721@dhcp22.suse.cz> From: Suren Baghdasaryan Date: Tue, 12 Mar 2019 10:15:40 -0700 Message-ID: Subject: Re: [RFC] simple_lmk: Introduce Simple Low Memory Killer for Android To: Michal Hocko Cc: Sultan Alsawaf , Greg Kroah-Hartman , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Todd Kjos , Martijn Coenen , Joel Fernandes , Christian Brauner , Ingo Molnar , Peter Zijlstra , LKML , devel@driverdev.osuosl.org, linux-mm , Tim Murray 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: On Tue, Mar 12, 2019 at 9:58 AM Michal Hocko wrote: > > On Tue 12-03-19 09:37:41, Sultan Alsawaf wrote: > > I have not had a chance to look at PSI yet, but > > unless a PSI-enabled solution allows allocations to reach the same point as when > > the OOM killer is invoked (which is contradictory to what it sets out to do), LMK's job is to relieve memory pressure before we reach the boiling point at which OOM killer has to be invoked. If we wait that long it will definitely affect user experience. There might be usecases when you might not care about this but on interactive systems like Android it is important. > > then it cannot take advantage of all of the alternative memory-reclaim means > > employed in the slowpath, and will result in killing a process before it is > > _really_ necessary. I guess it's a matter of defining when is it _really_ necessary to kill. In Android case that should be when the user starts suffering from the delays caused by memory contention and that delay is exactly what PSI is measuring. > One more note. The above is true, but you can also hit one of the > thrashing reclaim behaviors and reclaim last few pages again and again > with the whole system really sluggish. That is what PSI is trying to > help with. > -- > Michal Hocko > SUSE Labs