From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=unavailable autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id DC6E37D90F for ; Wed, 7 Aug 2019 20:45:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389488AbfHGUpd (ORCPT ); Wed, 7 Aug 2019 16:45:33 -0400 Received: from mail-pl1-f193.google.com ([209.85.214.193]:44498 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388866AbfHGUpd (ORCPT ); Wed, 7 Aug 2019 16:45:33 -0400 Received: by mail-pl1-f193.google.com with SMTP id t14so42488009plr.11 for ; Wed, 07 Aug 2019 13:45:32 -0700 (PDT) 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=nVq2Lrz4oly1cbME+ru7uC/EUuUzNyfifYdkSD+WXws=; b=SKjwZ75o/bjl3P6himFnL+2MJNzMb2KlU9PecY9gL2OvoO+kAS5KzKleoxU5N6Eozn KPw8Qn8ix5JOtTRWXYGTvhdvMcOzAtYMnblQFIQJIJh/bMOFzKoN5j4jAbdrYEbb6aWF i4sTmbSnKu/H2O6vxlszhwMU0BMjebOmFC5TU= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=nVq2Lrz4oly1cbME+ru7uC/EUuUzNyfifYdkSD+WXws=; b=DLuA/3x0bU4U5Rwh2h63z1iP/I1fIWnFa9juCDNB7pTzR2tPnje6M7qFqq26fzrrsb 0DaMuxixp4KqBrkssJ9BXefLhRnjX/1vfNqCM9tZSaLd0sFj8hKurhff95biJwYqccq9 zA8dKKJCI6zkhljHvhUC9Gpti4y+fF3auEAlYRcBYqh8VKZRuFMxjPOD31uFskJceL3a 5tiorqeYxt7m1W8ivZe92Tc/Tnof0fUcmQamTSP03k4x34qOAaN96pWNkWUqzFlvIs1N gYZDZ4z0BVcaL0WIJLeaUuTix9kjr3FW3t59G40S3sknyk06fghnWyibjBUrzXyqVMy7 +6+g== X-Gm-Message-State: APjAAAVQEg1lUxpENS5nW491T1/weyQcospForslgmdDMA46mXYb9vc6 0me3aZWXVPagKCPNYx75/DNCVg== X-Google-Smtp-Source: APXvYqyVsQ2rxzfkbsU4s/td7a6F6w6wqVCgyV/YFH3HkbntL96f95eC7uJQ7+msGgxczb30VirUZA== X-Received: by 2002:a17:902:145:: with SMTP id 63mr10208710plb.55.1565210732270; Wed, 07 Aug 2019 13:45:32 -0700 (PDT) Received: from localhost ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id s22sm99446893pfh.107.2019.08.07.13.45.31 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Wed, 07 Aug 2019 13:45:31 -0700 (PDT) Date: Wed, 7 Aug 2019 16:45:30 -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 Subject: Re: [PATCH v5 1/6] mm/page_idle: Add per-pid idle page tracking using virtual index Message-ID: <20190807204530.GB90900@google.com> References: <20190807171559.182301-1-joel@joelfernandes.org> <20190807130402.49c9ea8bf144d2f83bfeb353@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190807130402.49c9ea8bf144d2f83bfeb353@linux-foundation.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, Aug 07, 2019 at 01:04:02PM -0700, Andrew Morton wrote: > On Wed, 7 Aug 2019 13:15:54 -0400 "Joel Fernandes (Google)" wrote: > > > In Android, we are using this for the heap profiler (heapprofd) which > > profiles and pin points code paths which allocates and leaves memory > > idle for long periods of time. This method solves the security issue > > with userspace learning the PFN, and while at it is also shown to yield > > better results than the pagemap lookup, the theory being that the window > > where the address space can change is reduced by eliminating the > > intermediate pagemap look up stage. In virtual address indexing, the > > process's mmap_sem is held for the duration of the access. > > So is heapprofd a developer-only thing? Is heapprofd included in > end-user android loads? If not then, again, wouldn't it be better to > make the feature Kconfigurable so that Android developers can enable it > during development then disable it for production kernels? 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? thanks, - Joel