From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754033Ab2INPLA (ORCPT ); Fri, 14 Sep 2012 11:11:00 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:38848 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751597Ab2INPK6 (ORCPT ); Fri, 14 Sep 2012 11:10:58 -0400 From: OGAWA Hirofumi To: Jan Kara Cc: Fengguang Wu , viro@zeniv.linux.org.uk, hch@lst.de, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Fix queueing work if !bdi_cap_writeback_dirty() References: <87wr002z39.fsf@devron.myhome.or.jp> <20120913063906.GA24974@localhost> <871ui6e4tl.fsf@devron.myhome.or.jp> <20120914111429.GA19509@localhost> <87r4q4n6r1.fsf@devron.myhome.or.jp> <20120914131952.GA4952@quack.suse.cz> <87ipbgn2gz.fsf@devron.myhome.or.jp> <20120914144543.GB4952@quack.suse.cz> Date: Sat, 15 Sep 2012 00:10:53 +0900 In-Reply-To: <20120914144543.GB4952@quack.suse.cz> (Jan Kara's message of "Fri, 14 Sep 2012 16:45:43 +0200") Message-ID: <878vccmygy.fsf@devron.myhome.or.jp> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.2.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Jan Kara writes: >> If flusher is working, it clears dirty flags of inode. But if those >> handers can't flush at the time, we have to do redirty or something to >> prevent the reclaim. > Well, if this is your only problem then I'd see better options than just > disabling flusher thread. If the inability to write inode is rare, then > redirtying seems like a reasonable option (despite I agree it's a bit > ugly). If the inability to write is common, then you'll probably have to do > the dirty inode tracking yourself in some list and expose inodes to VM when > they are ready to be written. Or you handle writing of inodes yourself but > leave writing of pages on flusher thread... Basically all data can be data-integrity write like data logging, so it would be more than common. And ->writepages() will also ignore WBC_SYNC_NONE. > Because when you disable flusher thread completely you have to put all the > smarts to avoid livelocks, keep fairness among processes, write old data, > keep number of dirty pages under control into your filesystem which leads > to a lot of duplication. I'm not sure what you meant though. What is the difference with ignoring WBC_SYNC_NONE? Thanks. -- OGAWA Hirofumi