From mboxrd@z Thu Jan 1 00:00:00 1970 From: Artem Bityutskiy Subject: [PATCHv2 04/11] writeback: do not lose wake-ups in the forker thread - 2 Date: Wed, 21 Jul 2010 12:31:39 +0300 Message-ID: <1279704706-1267-5-git-send-email-dedekind1@gmail.com> References: <1279704706-1267-1-git-send-email-dedekind1@gmail.com> Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: Jens Axboe Return-path: Received: from smtp.nokia.com ([192.100.122.230]:52633 "EHLO mgw-mx03.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991Ab0GUJc0 (ORCPT ); Wed, 21 Jul 2010 05:32:26 -0400 In-Reply-To: <1279704706-1267-1-git-send-email-dedekind1@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: From: Artem Bityutskiy Currently, if someone submits jobs for the default bdi, we can lose wake-up events. E.g., this can happen if 'bdi_queue_work()' is called when 'bdi_forker_thread()' is executing code after 'wb_do_writeback(me, 0)', but before 'set_current_state(TASK_INTERRUPTIBLE)'. This situation is unlikely, and the result is not very severe - we'll just delay the execution of the work, but this is still not very nice. This patch fixes the issue by checking whether the default bdi has works before the forker thread goes sleep. Signed-off-by: Artem Bityutskiy --- mm/backing-dev.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 0ea5e4c..ae44417 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -358,6 +358,10 @@ static int bdi_forker_thread(void *ptr) bdi_add_default_flusher_thread(bdi); } + /* Keep working if default bdi still has things to do */ + if (!list_empty(&me->bdi->work_list)) + __set_current_state(TASK_RUNNING); + if (list_empty(&bdi_pending_list)) { unsigned long wait; -- 1.7.1.1