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[209.85.220.65]) by mx.google.com with SMTPS id a1sor191258pjv.18.2019.08.07.13.44.52 for (Google Transport Security); Wed, 07 Aug 2019 13:44:52 -0700 (PDT) Received-SPF: pass (google.com: domain of joel@joelfernandes.org designates 209.85.220.65 as permitted sender) client-ip=209.85.220.65; Authentication-Results: mx.google.com; dkim=pass header.i=@joelfernandes.org header.s=google header.b=cvR0USsq; spf=pass (google.com: domain of joel@joelfernandes.org designates 209.85.220.65 as permitted sender) smtp.mailfrom=joel@joelfernandes.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=itaaHUuDhcUmWvWTJL4zW8mOnytMPij6pAOeeM3m1Hg=; b=cvR0USsq4TrVGI/7AHhxTvBLliSSP311yfq2eMIv0HZPy5zvZSgUkA9hOQuqwUwOmK tW59Vs41S3Z4cN2lbD7CBiabk1kuZyNcNbwelUz8x6sT4Q/qw4los5KJ1TsmL/bCkQ6a NbDSeg5PosKj8KNSTPFRKtihsP13TwsNRRQSw= X-Google-Smtp-Source: APXvYqzxGRsJN8tg0/I87Pfq2FlyH6V5p4w6lM9eq6TQXsCKYWlpRWdYAkMSEIlSnT6YRM40KG3l1w== X-Received: by 2002:a17:90a:bb8a:: with SMTP id v10mr319911pjr.78.1565210692050; Wed, 07 Aug 2019 13:44:52 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id j1sm126143263pgl.12.2019.08.07.13.44.50 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 07 Aug 2019 13:44:51 -0700 (PDT) Date: Wed, 7 Aug 2019 16:44:49 -0400 From: Joel Fernandes To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Alexey Dobriyan , Borislav Petkov , Brendan Gregg , Catalin Marinas , Christian Hansen , dancol@google.com, fmayer@google.com, "H. Peter Anvin" , Ingo Molnar , Jonathan Corbet , Kees Cook , kernel-team@android.com, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Michal Hocko , Mike Rapoport , minchan@kernel.org, namhyung@google.com, paulmck@linux.ibm.com, Robin Murphy , Roman Gushchin , Stephen Rothwell , surenb@google.com, Thomas Gleixner , tkjos@google.com, Vladimir Davydov , Vlastimil Babka , Will Deacon , Brendan Gregg Subject: Re: [PATCH v4 1/5] mm/page_idle: Add per-pid idle page tracking using virtual indexing Message-ID: <20190807204449.GA90900@google.com> References: <20190805170451.26009-1-joel@joelfernandes.org> <20190806151921.edec128271caccb5214fc1bd@linux-foundation.org> <20190807100013.GC169551@google.com> <20190807130122.f148548c05ec07e7b716457e@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190807130122.f148548c05ec07e7b716457e@linux-foundation.org> 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 Wed, Aug 07, 2019 at 01:01:22PM -0700, Andrew Morton wrote: > On Wed, 7 Aug 2019 06:00:13 -0400 Joel Fernandes wrote: > > > > > 8 files changed, 376 insertions(+), 45 deletions(-) > > > > > > Quite a lot of new code unconditionally added to major architectures. > > > Are we confident that everyone will want this feature? > > > > I did not follow, could you clarify more? All of this diff stat is not to > > architecture code: > > > My point is that the patchset adds a lot of new code with no way in > which users can opt out. Almost everyone gets a fatter kernel - how > many of those users will actually benefit from it? > > If "not many" then shouldn't we be making it Kconfigurable? Almost all of this code is already configurable with CONFIG_IDLE_PAGE_TRACKING. If you disable it, then all of this code gets disabled. Or are you referring to something else that needs to be made configurable? > Are there userspace tools which present this info to users or which > provide monitoring of some form? Do major distros ship those tools? > Do people use them? etcetera. > Android's heapprofd is what I was working on which is already using it (patch is not yet upstreamed). There is working set tracking which Sandeep (also from Android) said he wants to use. Minchan plans to use this in combination with ZRAM-based idle tracking. Mike Rappoport also showed some interest, but I am not sure where/how he is using it. These are just some of the usecases I am aware off. I am pretty sure more will come as well. thanks, - Joel