From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 069B8C32751 for ; Wed, 7 Aug 2019 20:01:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEB3D222FC for ; Wed, 7 Aug 2019 20:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565208089; bh=4Y+9zhlp+p8rLuzDnvz16xcsN6RE4cU24OrOaFTWccE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=tOdmee35Q0jXI5Au96yAJ9jfpzGU8mlM2SnlGSw6Wh1ftkHJ85NWx3uUp0uiywV7D TmXhOuzYTggoqz7A4oYz+ZhZYqUZl6IlReI6ufY7ccvooKJsMiAFIWmpG548Q7R63G KHVNmT4b5dEjwNv0ASxDwigZM88KH+wZscZN2NfY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730198AbfHGUBY (ORCPT ); Wed, 7 Aug 2019 16:01:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:46056 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729804AbfHGUBY (ORCPT ); Wed, 7 Aug 2019 16:01:24 -0400 Received: from akpm3.svl.corp.google.com (unknown [104.133.8.65]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6D7B42229C; Wed, 7 Aug 2019 20:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565208083; bh=4Y+9zhlp+p8rLuzDnvz16xcsN6RE4cU24OrOaFTWccE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zQWA7F1KoIQRCIl1yVyS0BiJUwsrwYEryJKxMHNxcX6ONB8eZ93zxVmeDQ44zmmr7 94PMczCgAY0emIRaZfVAe7SJ/fxtD+5a/tCkNgG8bpb7LPhysLSpabBlToJlvBBdXz 27kDL9DLZKISnabXM7rW3N8cStMFHWeqYCj5Xb7E= Date: Wed, 7 Aug 2019 13:01:22 -0700 From: Andrew Morton To: Joel Fernandes 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: <20190807130122.f148548c05ec07e7b716457e@linux-foundation.org> In-Reply-To: <20190807100013.GC169551@google.com> References: <20190805170451.26009-1-joel@joelfernandes.org> <20190806151921.edec128271caccb5214fc1bd@linux-foundation.org> <20190807100013.GC169551@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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? 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.