Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757938Ab3CTQSw (ORCPT ); Wed, 20 Mar 2013 12:18:52 -0400 Received: from cantor2.suse.de ([195.135.220.15]:45304 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752090Ab3CTQSv (ORCPT ); Wed, 20 Mar 2013 12:18:51 -0400 Date: Wed, 20 Mar 2013 17:18:47 +0100 From: Michal Hocko To: Mel Gorman Cc: Linux-MM , Jiri Slaby , Valdis Kletnieks , Rik van Riel , Zlatko Calusic , Johannes Weiner , dormando , Satoru Moriya , LKML Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Message-ID: <20130320161847.GD27375@dhcp22.suse.cz> References: <1363525456-10448-1-git-send-email-mgorman@suse.de> <1363525456-10448-2-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1363525456-10448-2-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1750 Lines: 54 On Sun 17-03-13 13:04:07, Mel Gorman wrote: [...] > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 88c5fed..4835a7a 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -2593,6 +2593,32 @@ static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining, > } > > /* > + * kswapd shrinks the zone by the number of pages required to reach > + * the high watermark. > + */ > +static void kswapd_shrink_zone(struct zone *zone, > + struct scan_control *sc, > + unsigned long lru_pages) > +{ > + unsigned long nr_slab; > + struct reclaim_state *reclaim_state = current->reclaim_state; > + struct shrink_control shrink = { > + .gfp_mask = sc->gfp_mask, > + }; > + > + /* Reclaim above the high watermark. */ > + sc->nr_to_reclaim = max(SWAP_CLUSTER_MAX, high_wmark_pages(zone)); OK, so the cap is at high watermark which sounds OK to me, although I would expect balance_gap being considered here. Is it not used intentionally or you just wanted to have a reasonable upper bound? I am not objecting to that it just hit my eyes. > + shrink_zone(zone, sc); > + > + reclaim_state->reclaimed_slab = 0; > + nr_slab = shrink_slab(&shrink, sc->nr_scanned, lru_pages); > + sc->nr_reclaimed += reclaim_state->reclaimed_slab; > + > + if (nr_slab == 0 && !zone_reclaimable(zone)) > + zone->all_unreclaimable = 1; > +} > + > +/* > * For kswapd, balance_pgdat() will work across all this node's zones until > * they are all at high_wmark_pages(zone). > * -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/