From mboxrd@z Thu Jan 1 00:00:00 1970 In-reply-to: <1195156900.22457.32.camel@lappy> (message from Peter Zijlstra on Thu, 15 Nov 2007 21:01:39 +0100) Subject: Re: [RFC] fuse writable mmap design References: <1195154530.22457.16.camel@lappy> <1195155759.22457.29.camel@lappy> <1195156900.22457.32.camel@lappy> Message-Id: From: Miklos Szeredi Date: Thu, 15 Nov 2007 21:11:37 +0100 Sender: owner-linux-mm@kvack.org Return-Path: To: a.p.zijlstra@chello.nl Cc: miklos@szeredi.hu, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org List-ID: > > 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 ] OK, I'll bear this in mind. Limiting the number of dirty+writeback to << dirty_thresh could still make sense, since it could prevent a nasty filesystem from pinning lots of kernel memory (which it can do without fuse in other ways, so this is not very important IMO). Miklos -- 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