From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752995AbcFJRsS (ORCPT ); Fri, 10 Jun 2016 13:48:18 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:32856 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751382AbcFJRsQ (ORCPT ); Fri, 10 Jun 2016 13:48:16 -0400 Date: Fri, 10 Jun 2016 19:48:00 +0200 From: Peter Zijlstra To: Vlastimil Babka Cc: Mel Gorman , Andrew Morton , Linux-MM , Rik van Riel , Johannes Weiner , LKML Subject: Re: [PATCH 02/27] mm, vmscan: Move lru_lock to the node Message-ID: <20160610174800.GU30909@twins.programming.kicks-ass.net> References: <1465495483-11855-1-git-send-email-mgorman@techsingularity.net> <1465495483-11855-3-git-send-email-mgorman@techsingularity.net> <575AED3E.3090705@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <575AED3E.3090705@suse.cz> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 10, 2016 at 06:39:26PM +0200, Vlastimil Babka wrote: > On 06/09/2016 08:04 PM, Mel Gorman wrote: > > Node-based reclaim requires node-based LRUs and locking. This is a > > preparation patch that just moves the lru_lock to the node so later patches > > are easier to review. It is a mechanical change but note this patch makes > > contention worse because the LRU lock is hotter and direct reclaim and kswapd > > can contend on the same lock even when reclaiming from different zones. > > > > Signed-off-by: Mel Gorman > > Acked-by: Johannes Weiner > > Acked-by: Vlastimil Babka > > One thing... > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > > index 9d71af25acf9..1e0ad06c33bd 100644 > > --- a/mm/page_alloc.c > > +++ b/mm/page_alloc.c > > @@ -5944,10 +5944,10 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat) > > zone->min_slab_pages = (freesize * sysctl_min_slab_ratio) / 100; > > #endif > > zone->name = zone_names[j]; > > + zone->zone_pgdat = pgdat; > > spin_lock_init(&zone->lock); > > - spin_lock_init(&zone->lru_lock); > > + spin_lock_init(zone_lru_lock(zone)); > > This means the same lock will be inited MAX_NR_ZONES times. Peterz told > me it's valid but weird. Probably better to do it just once, in case > lockdep/lock debugging gains some checks for that? Ah, I thought you meant using spin_lock_init() after the lock has already been used. This is fine.