From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chris Mason Subject: Re: [PATCH 1/2] writeback: Improve busyloop prevention Date: Fri, 14 Oct 2011 15:31:13 -0400 Message-ID: <1318620308-sup-2416@shiny> References: <1318453043-32057-1-git-send-email-jack@suse.cz> <1318453043-32057-2-git-send-email-jack@suse.cz> <20111013142638.GB6938@localhost> <20111013201354.GC27363@quack.suse.cz> <20111014071802.GB25687@infradead.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Jan Kara , Wu Fengguang , "linux-fsdevel@vger.kernel.org" , Dave Chinner , linux-btrfs To: Christoph Hellwig Return-path: Received: from rcsinet15.oracle.com ([148.87.113.117]:36465 "EHLO rcsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756091Ab1JNTbv (ORCPT ); Fri, 14 Oct 2011 15:31:51 -0400 In-reply-to: <20111014071802.GB25687@infradead.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Excerpts from Christoph Hellwig's message of 2011-10-14 03:18:02 -0400: > What btrfs does for the btree inode is insane, and I'm pretty sure I > already complained about it. It really needs to stop registering that > inode with the writeback code and just driver it manually. Same as > other filesystems do for their "micro-managed" metadata. > So I think you probably don't like the inode and the part where we actively decide not to writeback when there isn't much dirty. Yes, it would be different if btrfs had its own LRU for the btrees, and if it maintained them such that the LRU understood it was better to kick out leaves than roots. I've really wanted to play with this for a while. -chris