From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 865196B0169 for ; Mon, 25 Jul 2011 19:41:02 -0400 (EDT) Received: by qyk32 with SMTP id 32so1391058qyk.14 for ; Mon, 25 Jul 2011 16:41:00 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20110725203705.GA21691@tassilo.jf.intel.com> References: <1311625159-13771-1-git-send-email-jweiner@redhat.com> <1311625159-13771-5-git-send-email-jweiner@redhat.com> <20110725203705.GA21691@tassilo.jf.intel.com> Date: Tue, 26 Jul 2011 08:40:59 +0900 Message-ID: Subject: Re: [patch 4/5] mm: writeback: throttle __GFP_WRITE on per-zone dirty limits From: Minchan Kim Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: To: Andi Kleen Cc: Johannes Weiner , linux-mm@kvack.org, Dave Chinner , Christoph Hellwig , Mel Gorman , Andrew Morton , Wu Fengguang , Rik van Riel , Jan Kara , linux-kernel@vger.kernel.org Hi Andi, On Tue, Jul 26, 2011 at 5:37 AM, Andi Kleen wrote: >> The global dirty limits are put in proportion to the respective zone's >> amount of dirtyable memory and the allocation denied when the limit of >> that zone is reached. >> >> Before the allocation fails, the allocator slowpath has a stage before >> compaction and reclaim, where the flusher threads are kicked and the >> allocator ultimately has to wait for writeback if still none of the >> zones has become eligible for allocation again in the meantime. >> > > I don't really like this. It seems wrong to make memory > placement depend on dirtyness. > > Just try to explain it to some system administrator or tuner: her > head will explode and for good reasons. > > On the other hand I like doing round-robin in filemap by default > (I think that is what your patch essentially does) > We should have made =C2=A0this default long ago. It avoids most of the > "IO fills up local node" problems people run into all the time. > > So I would rather just change the default in filemap allocation. > > That's also easy to explain. Just out of curiosity. Why do you want to consider only filemap allocation, not IO(ie, filemap + sys_[read/write]) allocation? --=20 Kind regards, Minchan Kim -- 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