From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f171.google.com (mail-pd0-f171.google.com [209.85.192.171]) by kanga.kvack.org (Postfix) with ESMTP id C3A1C900003 for ; Mon, 7 Jul 2014 15:13:49 -0400 (EDT) Received: by mail-pd0-f171.google.com with SMTP id fp1so5824943pdb.2 for ; Mon, 07 Jul 2014 12:13:49 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id rp15si41655988pab.235.2014.07.07.12.13.47 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 07 Jul 2014 12:13:48 -0700 (PDT) Date: Mon, 7 Jul 2014 12:13:46 -0700 From: Andrew Morton Subject: Re: [PATCH v3 0/3] free reclaimed pages by paging out instantly Message-Id: <20140707121346.1487c20e2a9365325e3a81a6@linux-foundation.org> In-Reply-To: <20140703005949.GC21751@bbox> References: <1404260029-11525-1-git-send-email-minchan@kernel.org> <20140702134215.2bf830dcb904c34bd2e2b9e8@linux-foundation.org> <20140703005949.GC21751@bbox> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Rik van Riel , Hugh Dickins , Johannes Weiner , Michal Hocko On Thu, 3 Jul 2014 09:59:49 +0900 Minchan Kim wrote: > > > Most of field in vmstat are not changed too much but things I can notice > > > is allocstall and pgrotated. We could save allocstall(ie, direct relcaim) > > > and pgrotated very much. > > > > > > Welcome testing, review and any feedback! > > > > Well, it will worsen IRQ latencies and it's all more code for us to > > maintain. I think I'd like to see a better story about the end-user > > benefits before proceeding. > > The motivation was from per-process reclaim(which was internal feature > yet and and I will repost it soon). > It's a feature for us to manage memory from platform so that we could > avoid reclaim. > > Anyway, userspace expect they could see increased free pages in vmstat > after they have done per-process reclaim so the logic of userspace > will control their next action depending on the number of current > free page but it doesn't work with existing rotation logic, expecially > anon swap write pages. > > When I posted this patchset firstly, Rik was positive and I thought > this feature is useful for everyone as well as per-process reclaim > and don't want to make noise this patchset with perpcoess reclaim. > > https://lkml.org/lkml/2013/5/12/174 > https://lkml.org/lkml/2013/5/14/484 > > Could you tell me what should I do to proceed? Quantify the gains, quantify the losses then demonstrate that the benefits of the gains exceeds the cost of the losses plus the cost of ongoing maintenance! -- 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