From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f175.google.com (mail-wi0-f175.google.com [209.85.212.175]) by kanga.kvack.org (Postfix) with ESMTP id C9D196B0038 for ; Mon, 24 Aug 2015 04:51:31 -0400 (EDT) Received: by wijp15 with SMTP id p15so70451431wij.0 for ; Mon, 24 Aug 2015 01:51:31 -0700 (PDT) Received: from mail-wi0-f171.google.com (mail-wi0-f171.google.com. [209.85.212.171]) by mx.google.com with ESMTPS id u9si30772141wjx.196.2015.08.24.01.51.29 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Aug 2015 01:51:30 -0700 (PDT) Received: by wijp15 with SMTP id p15so70450608wij.0 for ; Mon, 24 Aug 2015 01:51:29 -0700 (PDT) Date: Mon, 24 Aug 2015 10:51:27 +0200 From: Michal Hocko Subject: Re: [PATCH v5 2/2] mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status Message-ID: <20150824085127.GB17078@dhcp22.suse.cz> References: <20150812000336.GB32192@hori1.linux.bs1.fc.nec.co.jp> <1440059182-19798-1-git-send-email-n-horiguchi@ah.jp.nec.com> <1440059182-19798-3-git-send-email-n-horiguchi@ah.jp.nec.com> <20150820110004.GB4632@dhcp22.suse.cz> <20150820233450.GB10807@hori1.linux.bs1.fc.nec.co.jp> <20150821065321.GD23723@dhcp22.suse.cz> <20150821163033.GA4600@Sligo.logfs.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150821163033.GA4600@Sligo.logfs.org> Sender: owner-linux-mm@kvack.org List-ID: To: =?iso-8859-1?Q?J=F6rn?= Engel Cc: Naoya Horiguchi , Andrew Morton , David Rientjes , Mike Kravetz , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Naoya Horiguchi On Fri 21-08-15 09:30:33, Jorn Engel wrote: > On Fri, Aug 21, 2015 at 08:53:21AM +0200, Michal Hocko wrote: > > On Thu 20-08-15 23:34:51, Naoya Horiguchi wrote: > > [...] > > > > Reading a single file is, of course, easier but is it really worth the > > > > additional code? I haven't really looked at the patch so I might be > > > > missing something but what would be an advantage over reading > > > > /proc//smaps and extracting the information from there? > > > > > > My first idea was just "users should feel it useful", but permission as David > > > commented sounds a good technical reason to me. > > > > 9 files changed, 112 insertions(+), 1 deletion(-) > > > > is quite a lot especially when it touches hot paths like fork so it > > better should have a good usecase. I have already asked in the other > > email but is actually anybody requesting this? Nice to have is not > > a good justification IMO. > > I need some way to judge the real rss of a process, including huge > pages. No strong opinion on implementation details, but something is > clearly needed. The current implementation makes me worry. Is the per hstate break down really needed? The implementation would be much more easier without it. > If you have processes with 99% huge pages, you are currently reduced to > guesswork. If you have 99% of hugetlb pages then your load is rather specific and I would argue that /proc//smaps (after patch 1) is a much better way to get what you want. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org