From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f198.google.com (mail-io0-f198.google.com [209.85.223.198]) by kanga.kvack.org (Postfix) with ESMTP id A574D6B0253 for ; Wed, 20 Sep 2017 11:05:57 -0400 (EDT) Received: by mail-io0-f198.google.com with SMTP id k101so4755101iod.1 for ; Wed, 20 Sep 2017 08:05:57 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id t21sor860116ioi.364.2017.09.20.08.05.55 for (Google Transport Security); Wed, 20 Sep 2017 08:05:56 -0700 (PDT) Subject: Re: [PATCH 5/6] fs-writeback: move nr_pages == 0 logic to one location References: <1505850787-18311-1-git-send-email-axboe@kernel.dk> <1505850787-18311-6-git-send-email-axboe@kernel.dk> <20170920144159.GF11106@quack2.suse.cz> From: Jens Axboe Message-ID: <33ba51dc-cb93-ad8c-d973-41ac12cb9e90@kernel.dk> Date: Wed, 20 Sep 2017 09:05:51 -0600 MIME-Version: 1.0 In-Reply-To: <20170920144159.GF11106@quack2.suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, hannes@cmpxchg.org, clm@fb.com On 09/20/2017 08:41 AM, Jan Kara wrote: > On Tue 19-09-17 13:53:06, Jens Axboe wrote: >> Now that we have no external callers of wb_start_writeback(), >> we can move the nr_pages == 0 logic into that function. >> >> Signed-off-by: Jens Axboe > > ... > >> +static unsigned long get_nr_dirty_pages(void) >> +{ >> + return global_node_page_state(NR_FILE_DIRTY) + >> + global_node_page_state(NR_UNSTABLE_NFS) + >> + get_nr_dirty_inodes(); >> +} >> + >> static void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, >> bool range_cyclic, enum wb_reason reason) >> { >> @@ -942,6 +953,12 @@ static void wb_start_writeback(struct bdi_writeback *wb, long nr_pages, >> return; >> >> /* >> + * If someone asked for zero pages, we write out the WORLD >> + */ >> + if (!nr_pages) >> + nr_pages = get_nr_dirty_pages(); >> + > > So for 'wb' we have a better estimate of the amount we should write - use > wb_stat_sum(wb, WB_RECLAIMABLE) statistics - that is essentially dirty + > unstable_nfs broken down to bdi_writeback. I don't mind making that change, but I think that should be a separate patch. We're using get_nr_dirty_pages() in existing locations where we have the 'wb', like in wb_check_old_data_flush(). -- Jens Axboe -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org