From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f200.google.com (mail-wj0-f200.google.com [209.85.210.200]) by kanga.kvack.org (Postfix) with ESMTP id 18D826B0038 for ; Wed, 4 Jan 2017 09:51:46 -0500 (EST) Received: by mail-wj0-f200.google.com with SMTP id d17so49972602wjx.5 for ; Wed, 04 Jan 2017 06:51:46 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id is8si1776216wjb.233.2017.01.04.06.51.44 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 04 Jan 2017 06:51:45 -0800 (PST) Subject: Re: [PATCH 5/7] mm, vmscan: extract shrink_page_list reclaim counters into a struct References: <20170104101942.4860-1-mhocko@kernel.org> <20170104101942.4860-6-mhocko@kernel.org> From: Vlastimil Babka Message-ID: <01c9e2c9-3a04-48cd-cf0e-265db33d1a24@suse.cz> Date: Wed, 4 Jan 2017 15:51:43 +0100 MIME-Version: 1.0 In-Reply-To: <20170104101942.4860-6-mhocko@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko , Andrew Morton Cc: Mel Gorman , Johannes Weiner , Minchan Kim , Hillf Danton , linux-mm@kvack.org, LKML , Michal Hocko On 01/04/2017 11:19 AM, Michal Hocko wrote: > From: Michal Hocko > > shrink_page_list returns quite some counters back to its caller. Extract > the existing 5 into struct reclaim_stat because this makes the code > easier to follow and also allows further counters to be returned. > > While we are at it, make all of them unsigned rather than unsigned long > as we do not really need full 64b for them (we never scan more than > SWAP_CLUSTER_MAX pages at once). This should reduce some stack space. > > This patch shouldn't introduce any functional change. [...] > @@ -1266,11 +1270,13 @@ static unsigned long shrink_page_list(struct list_head *page_list, > list_splice(&ret_pages, page_list); > count_vm_events(PGACTIVATE, pgactivate); > > - *ret_nr_dirty += nr_dirty; > - *ret_nr_congested += nr_congested; > - *ret_nr_unqueued_dirty += nr_unqueued_dirty; > - *ret_nr_writeback += nr_writeback; > - *ret_nr_immediate += nr_immediate; > + if (stat) { > + stat->nr_dirty = nr_dirty; > + stat->nr_congested = nr_congested; > + stat->nr_unqueued_dirty = nr_unqueued_dirty; > + stat->nr_writeback = nr_writeback; > + stat->nr_immediate = nr_immediate; > + } This change of '+=' to '=' raised my eybrows, but it seems both callers don't care so this is indeed no functional change and potentially faster. -- 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