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[213.151.95.130]) by smtp.gmail.com with ESMTPSA id 4sm8426509wmd.33.2019.11.25.03.47.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 Nov 2019 03:47:09 -0800 (PST) Date: Mon, 25 Nov 2019 12:47:08 +0100 From: Michal Hocko To: David Rientjes Cc: Mel Gorman , Andrew Morton , Vlastimil Babka , Linus Torvalds , Andrea Arcangeli , "Kirill A. Shutemov" , Linux Kernel Mailing List , Linux-MM Subject: Re: [patch for-5.3 0/4] revert immediate fallback to remote hugepages Message-ID: <20191125114708.GI31714@dhcp22.suse.cz> References: <08a3f4dd-c3ce-0009-86c5-9ee51aba8557@suse.cz> <20191029151549.GO31513@dhcp22.suse.cz> <20191029143351.95f781f09a9fbf254163d728@linux-foundation.org> <20191105130253.GO22672@dhcp22.suse.cz> <20191106073521.GC8314@dhcp22.suse.cz> <20191113112042.GG28938@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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 Sun 24-11-19 16:10:53, David Rientjes wrote: [...] > So my question would be: if we know the previous behavior that allowed > excessive swap and recalling into compaction was deemed harmful for the > local node, why do we now believe it cannot be harmful if done for all > system memory? I have to say that I got lost in your explanation. I have already pointed this out in a previous email you didn't reply to. But the main difference to previous __GFP_THISNODE behavior is that it is used along with __GFP_NORETRY and that reduces the overall effort of the reclaim AFAIU. If that is not the case then please be _explicit_ why. Having test results from Andrea would be really appreciated of course but he seems to be too busy to do that (or maybe not interested anymore). I do not see any real reason to hold on this patch based on hand waving though. So either we have some good reasoning to argue against the patch or a good testing results or we should go ahead. As things stand right now, THP success rate went down after your last changes for _very simple_ workloads. This needs addressing which I hope we do agree on. -- Michal Hocko SUSE Labs