From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id E90F18D0046 for ; Thu, 17 Mar 2011 12:24:36 -0400 (EDT) Received: from hpaq6.eem.corp.google.com (hpaq6.eem.corp.google.com [172.25.149.6]) by smtp-out.google.com with ESMTP id p2HGOY3j008242 for ; Thu, 17 Mar 2011 09:24:34 -0700 Received: from qwb8 (qwb8.prod.google.com [10.241.193.72]) by hpaq6.eem.corp.google.com with ESMTP id p2HGM9si002596 (version=TLSv1/SSLv3 cipher=RC4-SHA bits=128 verify=NOT) for ; Thu, 17 Mar 2011 09:24:33 -0700 Received: by qwb8 with SMTP id 8so2225270qwb.38 for ; Thu, 17 Mar 2011 09:24:29 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110317155139.GA16195@infradead.org> References: <1299623475-5512-1-git-send-email-jack@suse.cz> <20110317155139.GA16195@infradead.org> Date: Thu, 17 Mar 2011 09:24:28 -0700 Message-ID: Subject: Re: [PATCH RFC 0/5] IO-less balance_dirty_pages() v2 (simple approach) From: Curt Wohlgemuth Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Christoph Hellwig Cc: Jan Kara , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Wu Fengguang , Peter Zijlstra , Andrew Morton Hi Christoph: On Thu, Mar 17, 2011 at 8:51 AM, Christoph Hellwig wrot= e: > On Thu, Mar 17, 2011 at 08:46:23AM -0700, Curt Wohlgemuth wrote: >> But if one of one's goals is to provide some sort of disk isolation base= d on >> cgroup parameters, than having at most one stream of write requests >> effectively neuters the IO scheduler. > > If you use any kind of buffered I/O you already fail in that respect. > Writeback from balance_dirty_page really is just the wort case right now > with more I/O supposed to be handled by the background threads. =A0So if > you want to implement isolation properly you need to track the > originator of the I/O between the copy to the pagecache and actual > writeback. Which is indeed part of the patchset I referred to above ("[RFC] [PATCH 0/6] Provide cgroup isolation for buffered writes", https://lkml.org/lkml/2011/3/8/332 ). Thanks, Curt -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org