From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout.gmx.net (mout.gmx.net [212.227.17.20]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C6D832C9D for ; Wed, 1 Dec 2021 04:32:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1638333153; bh=AKqwOapI/P1+DWQeKxnW+oEXUCmtI8Mg9I4HQaXQU7Y=; h=X-UI-Sender-Class:Subject:From:To:Cc:Date:In-Reply-To:References; b=UqkvJd2ahQIAuyl9j1YzgMG50sqR/5OpomlZmypMwqGiTP85NDvoqaNiUiBXWvMcP oOxyFJEodjklEnh1Tgmq10Z9aT9tc1LZty2e/w+RPyobq6RF6StEhz1pJuxeSE8RpQ 43zKm1jPIRLT7y3elFCvFlUel/o2H98g3R4Zv1H4= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from homer.fritz.box ([185.221.151.67]) by mail.gmx.net (mrgmx104 [212.227.17.168]) with ESMTPSA (Nemesis) id 1MzQgC-1mer331C6q-00vNDD; Wed, 01 Dec 2021 05:32:33 +0100 Message-ID: Subject: Re: [PATCH 1/1] mm: vmscan: Reduce throttling due to a failure to make progress From: Mike Galbraith To: Mel Gorman Cc: Alexey Avramov , Andrew Morton , Michal Hocko , Vlastimil Babka , Rik van Riel , Darrick Wong , regressions@lists.linux.dev, Linux-fsdevel , Linux-MM , LKML Date: Wed, 01 Dec 2021 05:32:31 +0100 In-Reply-To: <20211130130935.GR3366@techsingularity.net> References: <20211125151853.8540-1-mgorman@techsingularity.net> <20211127011246.7a8ac7b8@mail.inbox.lv> <20211129150117.GO3366@techsingularity.net> <20211130112244.GQ3366@techsingularity.net> <20211130130935.GR3366@techsingularity.net> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.1 Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:P3WByZj5IDN7qpCbMRUdgA/WTK8GizMAVsIN61yMDHaJW9Aq2Vz VhFrMz9er39O0JZqazAdxSygFPMsoyMR3PTvUx9VypiXulAqCVgzb9J7H7Htx8D1Etg3sLa bK3XbFZHps/IPIfH7yrllKNJF60EYe1nKInrlk3smXjFEiVCJ7yTDaoHjFHEEOBxIOkJoUn a1Eaa8x/hEaL9TpLNKabQ== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:chVfPrHgdZ4=:MJ0T8ADoYCth8LEO+meIi+ ZN8JysXyiMCqpzeOVqZYC6dfK0v4Y891gd6DUwgcTwx0olADHGZALa8eEmEi95fON0vt+yjQ3 LSq6PhdpcMCKIvhunYKWk4e7Fy1KmPGXrQ40FlqoiAHXT+udHMTRjSqciLG5mwcONHRJ4VKO7 EIZfB63BSWr2LK8YpEWQ8VHRenUBhmMGg+nuVUsrys4qBBqFZGnCofltdmacE869mX6QSElnn 7XalJKsfY7MK0f+ySzPfiJ04PFDQT3IRnIS2qsauYYOo2Hf7YemUQFrRc9sfHtKsX/cWrQvZh Y3U+iHBl05NThO93Ey2JeNJNkYnH/pNv/7K0ADDPr0eG1+2bmliwKEvda6eUL/uDj1HNcwm8W CbwVE4j/DBEX0bpfcVAS10TDpL6g3BN2Mn5trwne16XRjL81fPp7M67mp+SdZ/9NcuKJU7wMA +O1jKm8X+Tjb21uz9Jgp/586nnYQrCmLpy6Dckuqruda/j1oEWYOUysRs1pGxR5YX09SL38Q8 vprLFMCvlpHcIpd1MdTCgC6/8oDwzFEokbzgubfphTKq2/QjPMD1i4C6IqVk3QqD6zme7eCLu JVOZEv8aIopvtBnpB9EiaWqFE/Pgof6HmuN7To/jowyL9gNBk0nwa/iOL0POhqTmEFb3L6oBO 6qcX4UHLYjrzK/W7/WNJaDbeXn6YLUlDrzmQzEENH0nFNlP1H3c35TWGvCL2rxVYZ5mXY0Juf Su7p9LUtlZAxB9Hmh/tVzY+7cxbAWDGcaAaUd8XVRVY6FkxBM8FFp1OrKTo4c3EWcrh+FZBQx dOOtdj64MLAlrTMngMCyTQlNWqiHWEKk734q98lZdpsxQccVh+w+demR2enRbBEpUEWGqZXeS 9jGfp7zV+zNPi6KFhFjGIdgBuYTi9EEXTizId2XOd7CMYYifcyC+4vlwligURhfl+hbGSnm2/ RZ/f44sIas5T+dR9SItkN3hexqvATpuHAlWffhBVuBRAA+WDJacPekOCgDsnAkiNPKWLEpnKd XgX9mBD++xoOneEVMfrBlog7ijKOVRWPUyCh74MHvkYogPLM4jLKZjaekxsXFDpFY8HoGGokU aupIRr3fRJdugk= On Tue, 2021-11-30 at 13:09 +0000, Mel Gorman wrote: > On Tue, Nov 30, 2021 at 01:51:10PM +0100, Mike Galbraith wrote: > > On Tue, 2021-11-30 at 13:00 +0100, Mike Galbraith wrote: > > > On Tue, 2021-11-30 at 11:22 +0000, Mel Gorman wrote: > > > > On Tue, Nov 30, 2021 at 11:14:32AM +0100, Mike Galbraith wrote: > > > > > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0} > > > > > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0if (2 * write_pendi= ng <=3D reclaimable) > > > > > > > > > > That is always true here... > > > > > > > > > > > > > Always true for you or always true in general? > > > > > > "Here" as in the boxen located at my GPS coordinates :) > > > > > > > The intent of the check is "are a majority of reclaimable pages > > > > marked WRITE_PENDING?". It's similar to the check that existed pri= or > > > > to 132b0d21d21f ("mm/page_alloc: remove the throttling logic from = the > > > > page allocator"). > > > > > > I'll put my trace_printk() back and see if I can't bend-adjust it. > > > > As it sits, write_pending is always 0 with tail /dev/zero. > > > > That is not a surprise for the test in question as it doesn't trigger > a case where there are lots of page cache being marked dirty and write > pending. I found a way to make it go false, around 80% of the time on the way to the first oom-kill in fact. Starting 2 memcg stress instances and a memory sized bonnie did the trick. 'course getting those started was the last thing my desktop did before taking up residence on spinning rust and staying there for the 10 minute test duration, mouse pointer didn't even manage to twitch :) That's way worse than having box try to swallow /dev/zero, that gets killed pretty quickly with your latest patch. The grim reaper tried to help with nutty overcommit, but two kills in 10 minutes wasn't enough. -Mike