From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Subject: Re: [PATCH 5/6] fs-writeback: move nr_pages == 0 logic to one location To: Jan Kara Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, hannes@cmpxchg.org, clm@fb.com References: <1505850787-18311-1-git-send-email-axboe@kernel.dk> <1505850787-18311-6-git-send-email-axboe@kernel.dk> <20170920144159.GF11106@quack2.suse.cz> <33ba51dc-cb93-ad8c-d973-41ac12cb9e90@kernel.dk> <20170920153627.GI11106@quack2.suse.cz> From: Jens Axboe Message-ID: <7c7de06e-0621-b121-917a-7abbd0e676d7@kernel.dk> Date: Wed, 20 Sep 2017 09:40:18 -0600 MIME-Version: 1.0 In-Reply-To: <20170920153627.GI11106@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: On 09/20/2017 09:36 AM, Jan Kara wrote: > On Wed 20-09-17 09:05:51, Jens Axboe wrote: >> 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(). > > Good point and fully agreed. So you can add: > > Reviewed-by: Jan Kara Thanks Jan, added. I just sent out the new version, mainly because the removal or 'nr_pages' changes the later patches a bit. All for the better, in my opinion. -- 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