From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail191.messagelabs.com (mail191.messagelabs.com [216.82.242.19]) by kanga.kvack.org (Postfix) with ESMTP id F40A46B004D for ; Sat, 15 Aug 2009 15:57:36 -0400 (EDT) Date: Sat, 15 Aug 2009 15:57:42 -0400 From: Christoph Hellwig Subject: Re: [rfc][patch] fs: turn iprune_mutex into rwsem Message-ID: <20090815195742.GA14842@infradead.org> References: <20090814152504.GA19195@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090814152504.GA19195@wotan.suse.de> Sender: owner-linux-mm@kvack.org To: Nick Piggin Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Jan Kara , Andrew Morton List-ID: On Fri, Aug 14, 2009 at 05:25:05PM +0200, Nick Piggin wrote: > Now I think the main problem is having the filesystem block (and do IO > in inode reclaim. The problem is that this doesn't get accounted well > and penalizes a random allocator with a big latency spike caused by > work generated from elsewhere. > > I think the best idea would be to avoid this. By design if possible, > or by deferring the hard work to an asynchronous context. If the latter, > then the fs would probably want to throttle creation of new work with > queue size of the deferred work, but let's not get into those details. I don't really see a good way to avoid this. For any filesystem that does some sort of preallocations we need to drop them in ->clear_inode. -- 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