Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764822AbXKOUCU (ORCPT ); Thu, 15 Nov 2007 15:02:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759439AbXKOUCJ (ORCPT ); Thu, 15 Nov 2007 15:02:09 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:60086 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759426AbXKOUCI (ORCPT ); Thu, 15 Nov 2007 15:02:08 -0500 Subject: Re: [RFC] fuse writable mmap design From: Peter Zijlstra To: Miklos Szeredi Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org In-Reply-To: References: <1195154530.22457.16.camel@lappy> <1195155759.22457.29.camel@lappy> Content-Type: text/plain Date: Thu, 15 Nov 2007 21:01:39 +0100 Message-Id: <1195156900.22457.32.camel@lappy> Mime-Version: 1.0 X-Mailer: Evolution 2.12.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1393 Lines: 37 On Thu, 2007-11-15 at 20:57 +0100, Miklos Szeredi wrote: > > The next point then, I'd expect your fuse_page_mkwrite() to push > > writeout of your 32-odd mmap pages instead of poll. > > You're talking about this: > > + wait_event(fc->writeback_waitq, > + fc->numwrite < FUSE_WRITEBACK_THRESHOLD); > > right? It's one of the things I need to clean out, there's no point > in fc->numwrite, which is essentially the same as the BDI_WRITEBACK > counter. > > OTOH, I'm thinking about adding a per-fs limit (adjustable for > privileged mounts) of dirty+writeback. > > I'm not sure how hard would it be to add support for this into > balance_dirty_pages(). So I'm thinking of a parameter in struct > backing_dev_info that is used to clip the calculated per-bdi threshold > below this maximum. > > How would that affect the proportions algorithm? What would happen to > the unused portion? Would it adapt to the slowed writeback and > allocate it to some other writer? The unused part is gone, I've not yet found a way to re-distribute this fairly. [ It's one of my open-problems, I can do a min_ratio per bdi, but not yet a max_ratio ] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/