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[209.85.208.179]) by smtp.gmail.com with ESMTPSA id q8-v6sm2692585lji.69.2018.12.03.11.28.24 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 03 Dec 2018 11:28:24 -0800 (PST) Received: by mail-lj1-f179.google.com with SMTP id s5-v6so12498868ljd.12 for ; Mon, 03 Dec 2018 11:28:24 -0800 (PST) X-Received: by 2002:a2e:2c02:: with SMTP id s2-v6mr11068811ljs.118.1543865303544; Mon, 03 Dec 2018 11:28:23 -0800 (PST) MIME-Version: 1.0 References: <20181127062503.GH6163@shao2-debian> <20181127205737.GI16136@redhat.com> <87tvk1yjkp.fsf@yhuang-dev.intel.com> <20181203181456.GK31738@dhcp22.suse.cz> <20181203183050.GL31738@dhcp22.suse.cz> <20181203185954.GM31738@dhcp22.suse.cz> In-Reply-To: <20181203185954.GM31738@dhcp22.suse.cz> From: Linus Torvalds Date: Mon, 3 Dec 2018 11:28:07 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [LKP] [mm] ac5b2c1891: vm-scalability.throughput -61.3% regression To: mhocko@kernel.org Cc: ying.huang@intel.com, Andrea Arcangeli , s.priebe@profihost.ag, mgorman@techsingularity.net, Linux List Kernel Mailing , alex.williamson@redhat.com, lkp@01.org, David Rientjes , kirill@shutemov.name, Andrew Morton , zi.yan@cs.rutgers.edu, Vlastimil Babka Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 3, 2018 at 10:59 AM Michal Hocko wrote: > > You are misinterpreting my words. I haven't dismissed anything. I do > recognize both usecases under discussion. > > I have merely said that a better THP locality needs more work and during > the review discussion I have even volunteered to work on that. We have two known patches that seem to have no real downsides. One is the patch posted by Andrea earlier in this thread, which seems to target just this known regression. The other seems to be to revert commit ac5b2c1891 and instead apply https://lore.kernel.org/lkml/alpine.DEB.2.21.1810081303060.221006@chino.kir.corp.google.com/ which also seems to be sensible. I'm not seeing why the KVM load would react badly to either of those models, and they are known to fix the google local-node issue. Linus