From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [RFC] fuse writable mmap design From: Peter Zijlstra 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 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Miklos Szeredi Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org List-ID: 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, 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