From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wj0-f199.google.com (mail-wj0-f199.google.com [209.85.210.199]) by kanga.kvack.org (Postfix) with ESMTP id 2877C6B026E for ; Thu, 26 Jan 2017 08:21:51 -0500 (EST) Received: by mail-wj0-f199.google.com with SMTP id kq3so39714341wjc.1 for ; Thu, 26 Jan 2017 05:21:51 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id w84si26525635wmg.121.2017.01.26.05.21.49 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 26 Jan 2017 05:21:49 -0800 (PST) Date: Thu, 26 Jan 2017 14:21:47 +0100 From: Michal Hocko Subject: Re: [PATCH 3/5] mm: vmscan: remove old flusher wakeup from direct reclaim path Message-ID: <20170126132147.GC7827@dhcp22.suse.cz> References: <20170123181641.23938-1-hannes@cmpxchg.org> <20170123181641.23938-4-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170123181641.23938-4-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com On Mon 23-01-17 13:16:39, Johannes Weiner wrote: > Direct reclaim has been replaced by kswapd reclaim in pretty much all > common memory pressure situations, so this code most likely doesn't > accomplish the described effect anymore. The previous patch wakes up > flushers for all reclaimers when we encounter dirty pages at the tail > end of the LRU. Remove the crufty old direct reclaim invocation. > > Signed-off-by: Johannes Weiner Acked-by: Michal Hocko > --- > mm/vmscan.c | 17 ----------------- > 1 file changed, 17 deletions(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 56ea8d24041f..915fc658de41 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2757,8 +2757,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > struct scan_control *sc) > { > int initial_priority = sc->priority; > - unsigned long total_scanned = 0; > - unsigned long writeback_threshold; > retry: > delayacct_freepages_start(); > > @@ -2771,7 +2769,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > sc->nr_scanned = 0; > shrink_zones(zonelist, sc); > > - total_scanned += sc->nr_scanned; > if (sc->nr_reclaimed >= sc->nr_to_reclaim) > break; > > @@ -2784,20 +2781,6 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist, > */ > if (sc->priority < DEF_PRIORITY - 2) > sc->may_writepage = 1; > - > - /* > - * Try to write back as many pages as we just scanned. This > - * tends to cause slow streaming writers to write data to the > - * disk smoothly, at the dirtying rate, which is nice. But > - * that's undesirable in laptop mode, where we *want* lumpy > - * writeout. So in laptop mode, write out the whole world. > - */ > - writeback_threshold = sc->nr_to_reclaim + sc->nr_to_reclaim / 2; > - if (total_scanned > writeback_threshold) { > - wakeup_flusher_threads(laptop_mode ? 0 : total_scanned, > - WB_REASON_VMSCAN); > - sc->may_writepage = 1; > - } > } while (--sc->priority >= 0); > > delayacct_freepages_end(); > -- > 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 -- 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