From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755878Ab2IMGbo (ORCPT ); Thu, 13 Sep 2012 02:31:44 -0400 Received: from mail.parknet.co.jp ([210.171.160.6]:38297 "EHLO mail.parknet.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755821Ab2IMGbm (ORCPT ); Thu, 13 Sep 2012 02:31:42 -0400 From: OGAWA Hirofumi To: Fengguang Wu Cc: viro@zeniv.linux.org.uk, jack@suse.cz, 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> <20120912024249.GB17922@localhost> <87sjan3c27.fsf@devron.myhome.or.jp> <20120913003337.GA16363@localhost> <87a9wueayc.fsf@devron.myhome.or.jp> <20120913060351.GA23682@localhost> Date: Thu, 13 Sep 2012 15:31:37 +0900 In-Reply-To: <20120913060351.GA23682@localhost> (Fengguang Wu's message of "Thu, 13 Sep 2012 14:03:51 +0800") Message-ID: <87627ie8mu.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 Fengguang Wu writes: >> >> I tested by custom bdi with BDI_CAP_NO_WRITEBACK - sync(2) blocked >> >> forever by this reason. >> > >> > What's your test script? How do you create/use that custom bdi? >> >> Ah, I wrote my kernel module to test. I guess there is no users in >> current kernel for now, because it doesn't work. > > OK. Got it. So I'd suggest to change the first chunk to a VM_BUG_ON(), > which should be enough to catch new bad callers. The other two chunks > look fine. Hm, if it changed to VM_BUG_ON(), we can't use BDI_CAP_NO_WRITEBACK to disable the writeback task (but allow inode cache reclaim) after all. Or you meant we don't allow to disable the writeback task? Thanks. -- OGAWA Hirofumi