From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752148AbdAZNN3 (ORCPT ); Thu, 26 Jan 2017 08:13:29 -0500 Received: from mx2.suse.de ([195.135.220.15]:40583 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751707AbdAZNN1 (ORCPT ); Thu, 26 Jan 2017 08:13:27 -0500 Date: Thu, 26 Jan 2017 14:13:23 +0100 From: Michal Hocko To: Johannes Weiner Cc: Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: Re: [PATCH 1/5] mm: vmscan: scan dirty pages even in laptop mode Message-ID: <20170126131322.GA7827@dhcp22.suse.cz> References: <20170123181641.23938-1-hannes@cmpxchg.org> <20170123181641.23938-2-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170123181641.23938-2-hannes@cmpxchg.org> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 23-01-17 13:16:37, Johannes Weiner wrote: > We have an elaborate dirty/writeback throttling mechanism inside the > reclaim scanner, but for that to work the pages have to go through > shrink_page_list() and get counted for what they are. Otherwise, we > mess up the LRU order and don't match reclaim speed to writeback. > > Especially during deactivation, there is never a reason to skip dirty > pages; nothing is even trying to write them out from there. Don't mess > up the LRU order for nothing, shuffle these pages along. absolutely agreed. > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > include/linux/mmzone.h | 2 -- > mm/vmscan.c | 14 ++------------ > 2 files changed, 2 insertions(+), 14 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index df992831fde7..338a786a993f 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -236,8 +236,6 @@ struct lruvec { > #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON)) > #define LRU_ALL ((1 << NR_LRU_LISTS) - 1) > > -/* Isolate clean file */ > -#define ISOLATE_CLEAN ((__force isolate_mode_t)0x1) > /* Isolate unmapped file */ > #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2) > /* Isolate for asynchronous migration */ > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 7bb23ff229b6..0d05f7f3b532 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -87,6 +87,7 @@ struct scan_control { > /* The highest zone to isolate pages for reclaim from */ > enum zone_type reclaim_idx; > > + /* Writepage batching in laptop mode; RECLAIM_WRITE */ > unsigned int may_writepage:1; > > /* Can mapped pages be reclaimed? */ > @@ -1373,13 +1374,10 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) > * wants to isolate pages it will be able to operate on without > * blocking - clean pages for the most part. > * > - * ISOLATE_CLEAN means that only clean pages should be isolated. This > - * is used by reclaim when it is cannot write to backing storage > - * > * ISOLATE_ASYNC_MIGRATE is used to indicate that it only wants to pages > * that it is possible to migrate without blocking > */ > - if (mode & (ISOLATE_CLEAN|ISOLATE_ASYNC_MIGRATE)) { > + if (mode & ISOLATE_ASYNC_MIGRATE) { > /* All the caller can do on PageWriteback is block */ > if (PageWriteback(page)) > return ret; > @@ -1387,10 +1385,6 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode) > if (PageDirty(page)) { > struct address_space *mapping; > > - /* ISOLATE_CLEAN means only clean pages */ > - if (mode & ISOLATE_CLEAN) > - return ret; > - > /* > * Only pages without mappings or that have a > * ->migratepage callback are possible to migrate > @@ -1731,8 +1725,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, > > if (!sc->may_unmap) > isolate_mode |= ISOLATE_UNMAPPED; > - if (!sc->may_writepage) > - isolate_mode |= ISOLATE_CLEAN; > > spin_lock_irq(&pgdat->lru_lock); > > @@ -1929,8 +1921,6 @@ static void shrink_active_list(unsigned long nr_to_scan, > > if (!sc->may_unmap) > isolate_mode |= ISOLATE_UNMAPPED; > - if (!sc->may_writepage) > - isolate_mode |= ISOLATE_CLEAN; > > spin_lock_irq(&pgdat->lru_lock); > > -- > 2.11.0 > > -- > 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 -- Michal Hocko SUSE Labs