From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 24 Apr 2007 03:00:21 -0700 From: Andrew Morton Subject: Re: [PATCH 10/10] mm: per device dirty threshold Message-Id: <20070424030021.a091018d.akpm@linux-foundation.org> In-Reply-To: References: <20070420155154.898600123@chello.nl> <20070420155503.608300342@chello.nl> <17965.29252.950216.971096@notabene.brown> <1177398589.26937.40.camel@twins> <1177403494.26937.59.camel@twins> <1177406817.26937.65.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Miklos Szeredi Cc: a.p.zijlstra@chello.nl, neilb@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com List-ID: On Tue, 24 Apr 2007 11:47:20 +0200 Miklos Szeredi wrote: > > Ahh, now I see; I had totally blocked out these few lines: > > > > pages_written += write_chunk - wbc.nr_to_write; > > if (pages_written >= write_chunk) > > break; /* We've done our duty */ > > > > yeah, those look dubious indeed... And reading back Neil's comments, I > > think he agrees. > > > > Shall we just kill those? > > I think we should. > > Athough I'm a little afraid, that Akpm will tell me again, that I'm a > stupid git, and that those lines are in fact vitally important ;) > It depends what they're replaced with. That code is there, iirc, to prevent a process from getting stuck in balance_dirty_pages() forever due to the dirtying activity of other processes. hm, we ask the process to write write_chunk pages each go around the loop. So if it wrote write-chunk/2 pages on the first pass it might end up writing write_chunk*1.5 pages total. I guess that's rare and doesn't matter much if it does happen - the upper bound is write_chunk*2-1, I think. -- 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