Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760617Ab0GWPJF (ORCPT ); Fri, 23 Jul 2010 11:09:05 -0400 Received: from smtp.nokia.com ([192.100.105.134]:52431 "EHLO mgw-mx09.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760098Ab0GWPF6 (ORCPT ); Fri, 23 Jul 2010 11:05:58 -0400 From: Artem Bityutskiy To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCHv4 09/14] writeback: restructure bdi forker loop a little Date: Fri, 23 Jul 2010 18:05:49 +0300 Message-Id: <1279897554-1526-10-git-send-email-dedekind1@gmail.com> X-Mailer: git-send-email 1.7.1.1 In-Reply-To: <1279897554-1526-1-git-send-email-dedekind1@gmail.com> References: <1279897554-1526-1-git-send-email-dedekind1@gmail.com> X-OriginalArrivalTime: 23 Jul 2010 15:05:50.0944 (UTC) FILETIME=[89F92600:01CB2A78] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2437 Lines: 75 From: Artem Bityutskiy This patch re-structures the loop which walks bdi a little. This is just a micro-step towards the coming change where the forker thread will kill the bdi threads. It should simplify reviewing the following changes, which would otherwise be larger. This patch also adds the 'bdi_cap_flush_forker(bdi)' condition check to the loop. The reason for this is that the forker thread can start _before_ the 'BDI_registered' flag is set (see 'bdi_register()'), so the WARN() statement will fire for the default bdi. I observed this warning at boot-up. This patch also amends comments a little. Signed-off-by: Artem Bityutskiy Reviewed-by: Christoph Hellwig --- mm/backing-dev.c | 28 +++++++++++++++++----------- 1 files changed, 17 insertions(+), 11 deletions(-) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index 672c17b..b788b8e 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -348,25 +348,31 @@ static int bdi_forker_thread(void *ptr) * a thread registered. If so, set that up. */ list_for_each_entry(bdi, &bdi_list, bdi_list) { - if (!bdi_cap_writeback_dirty(bdi)) - continue; - if (bdi->wb.task) - continue; - if (list_empty(&bdi->work_list) && - !bdi_has_dirty_io(bdi)) + bool have_dirty_io; + + if (!bdi_cap_writeback_dirty(bdi) || + bdi_cap_flush_forker(bdi)) continue; WARN(!test_bit(BDI_registered, &bdi->state), "bdi %p/%s is not registered!\n", bdi, bdi->name); - fork = true; + have_dirty_io = !list_empty(&bdi->work_list) || + wb_has_dirty_io(&bdi->wb); /* - * Set the pending bit - if someone will try to - * unregister this bdi - it'll wait on this bit. + * If the bdi has work to do, but the thread does not + * exist - create it. */ - set_bit(BDI_pending, &bdi->state); - break; + if (!bdi->wb.task && have_dirty_io) { + /* + * Set the pending bit - if someone will try to + * unregister this bdi - it'll wait on this bit. + */ + set_bit(BDI_pending, &bdi->state); + fork = true; + break; + } } spin_unlock_bh(&bdi_lock); -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/