From: Will Huck <will.huckk@gmail.com> To: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz>, Mel Gorman <mgorman@suse.de>, Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>, Valdis Kletnieks <Valdis.Kletnieks@vt.edu>, Zlatko Calusic <zcalusic@bitsync.net>, Johannes Weiner <hannes@cmpxchg.org>, dormando <dormando@rydia.net>, Satoru Moriya <satoru.moriya@hds.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Date: Fri, 22 Mar 2013 08:08:56 +0800 [thread overview] Message-ID: <514BA118.5000305@gmail.com> (raw) In-Reply-To: <514A59CD.3040108@redhat.com> Hi Rik, On 03/21/2013 08:52 AM, Rik van Riel wrote: > On 03/20/2013 12:18 PM, Michal Hocko wrote: >> 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. > > This is the maximum number of pages to reclaim, not the point > at which to stop reclaiming. What's the difference between the maximum number of pages to reclaim and the point at which to stop reclaiming? > > I assume Mel chose this value because it guarantees that enough > pages will have been freed, while also making sure that the value > is scaled according to zone size (keeping pressure between zones > roughly equal). >
WARNING: multiple messages have this Message-ID (diff)
From: Will Huck <will.huckk@gmail.com> To: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz>, Mel Gorman <mgorman@suse.de>, Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>, Valdis Kletnieks <Valdis.Kletnieks@vt.edu>, Zlatko Calusic <zcalusic@bitsync.net>, Johannes Weiner <hannes@cmpxchg.org>, dormando <dormando@rydia.net>, Satoru Moriya <satoru.moriya@hds.com>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Date: Fri, 22 Mar 2013 08:08:56 +0800 [thread overview] Message-ID: <514BA118.5000305@gmail.com> (raw) In-Reply-To: <514A59CD.3040108@redhat.com> Hi Rik, On 03/21/2013 08:52 AM, Rik van Riel wrote: > On 03/20/2013 12:18 PM, Michal Hocko wrote: >> 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. > > This is the maximum number of pages to reclaim, not the point > at which to stop reclaiming. What's the difference between the maximum number of pages to reclaim and the point at which to stop reclaiming? > > I assume Mel chose this value because it guarantees that enough > pages will have been freed, while also making sure that the value > is scaled according to zone size (keeping pressure between zones > roughly equal). > -- 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: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2013-03-22 0:09 UTC|newest] Thread overview: 260+ messages / expand[flat|nested] mbox.gz Atom feed top 2013-03-17 13:04 [RFC PATCH 0/8] Reduce system disruption due to kswapd Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 13:04 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-18 23:53 ` Simon Jeons 2013-03-18 23:53 ` Simon Jeons 2013-03-19 9:55 ` Mel Gorman 2013-03-19 9:55 ` Mel Gorman 2013-03-19 10:16 ` Simon Jeons 2013-03-19 10:16 ` Simon Jeons 2013-03-19 10:59 ` Mel Gorman 2013-03-19 10:59 ` Mel Gorman 2013-03-20 16:18 ` Michal Hocko 2013-03-20 16:18 ` Michal Hocko 2013-03-21 0:52 ` Rik van Riel 2013-03-21 0:52 ` Rik van Riel 2013-03-22 0:08 ` Will Huck [this message] 2013-03-22 0:08 ` Will Huck 2013-03-21 9:47 ` Mel Gorman 2013-03-21 9:47 ` Mel Gorman 2013-03-21 12:59 ` Michal Hocko 2013-03-21 12:59 ` Michal Hocko 2013-03-21 0:51 ` Rik van Riel 2013-03-21 0:51 ` Rik van Riel 2013-03-21 15:57 ` Johannes Weiner 2013-03-21 15:57 ` Johannes Weiner 2013-03-21 16:47 ` Mel Gorman 2013-03-21 16:47 ` Mel Gorman 2013-03-22 0:05 ` Will Huck 2013-03-22 0:05 ` Will Huck 2013-03-22 3:52 ` Rik van Riel 2013-03-22 3:52 ` Rik van Riel 2013-03-22 3:56 ` Will Huck 2013-03-22 3:56 ` Will Huck 2013-03-22 4:59 ` Will Huck 2013-03-22 4:59 ` Will Huck 2013-03-22 13:01 ` Rik van Riel 2013-03-22 13:01 ` Rik van Riel 2013-04-05 0:05 ` Will Huck 2013-04-05 0:05 ` Will Huck 2013-04-07 7:32 ` Will Huck 2013-04-07 7:32 ` Will Huck 2013-04-07 7:35 ` Will Huck 2013-04-07 7:35 ` Will Huck 2013-04-11 5:54 ` Will Huck 2013-04-11 5:54 ` Will Huck 2013-04-11 5:58 ` Will Huck 2013-04-11 5:58 ` Will Huck 2013-04-12 5:46 ` Ric Mason 2013-04-12 5:46 ` Ric Mason 2013-04-12 9:34 ` Mel Gorman 2013-04-12 9:34 ` Mel Gorman 2013-04-12 13:40 ` Rik van Riel 2013-04-12 13:40 ` Rik van Riel 2013-03-25 9:07 ` Michal Hocko 2013-03-25 9:07 ` Michal Hocko 2013-03-25 9:13 ` Jiri Slaby 2013-03-25 9:13 ` Jiri Slaby 2013-03-28 22:31 ` Jiri Slaby 2013-03-28 22:31 ` Jiri Slaby 2013-03-29 8:22 ` Michal Hocko 2013-03-29 8:22 ` Michal Hocko 2013-03-30 22:07 ` Jiri Slaby 2013-03-30 22:07 ` Jiri Slaby 2013-04-02 11:15 ` Mel Gorman 2013-04-02 11:15 ` Mel Gorman 2013-03-17 13:04 ` [PATCH 02/10] mm: vmscan: Obey proportional scanning requirements for kswapd Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:39 ` Andi Kleen 2013-03-17 14:39 ` Andi Kleen 2013-03-17 15:08 ` Mel Gorman 2013-03-17 15:08 ` Mel Gorman 2013-03-21 1:10 ` Rik van Riel 2013-03-21 1:10 ` Rik van Riel 2013-03-21 9:54 ` Mel Gorman 2013-03-21 9:54 ` Mel Gorman 2013-03-21 14:01 ` Michal Hocko 2013-03-21 14:01 ` Michal Hocko 2013-03-21 14:31 ` Mel Gorman 2013-03-21 14:31 ` Mel Gorman 2013-03-21 15:07 ` Michal Hocko 2013-03-21 15:07 ` Michal Hocko 2013-03-21 15:34 ` Mel Gorman 2013-03-21 15:34 ` Mel Gorman 2013-03-22 7:54 ` Michal Hocko 2013-03-22 7:54 ` Michal Hocko 2013-03-22 8:37 ` Mel Gorman 2013-03-22 8:37 ` Mel Gorman 2013-03-22 10:04 ` Michal Hocko 2013-03-22 10:04 ` Michal Hocko 2013-03-22 10:47 ` Michal Hocko 2013-03-22 10:47 ` Michal Hocko 2013-03-21 16:25 ` Johannes Weiner 2013-03-21 16:25 ` Johannes Weiner 2013-03-21 18:02 ` Mel Gorman 2013-03-21 18:02 ` Mel Gorman 2013-03-22 16:53 ` Johannes Weiner 2013-03-22 16:53 ` Johannes Weiner 2013-03-22 18:25 ` Mel Gorman 2013-03-22 18:25 ` Mel Gorman 2013-03-22 19:09 ` Johannes Weiner 2013-03-22 19:09 ` Johannes Weiner 2013-03-22 19:46 ` Mel Gorman 2013-03-22 19:46 ` Mel Gorman 2013-03-17 13:04 ` [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:36 ` Andi Kleen 2013-03-17 14:36 ` Andi Kleen 2013-03-17 15:09 ` Mel Gorman 2013-03-17 15:09 ` Mel Gorman 2013-03-18 7:02 ` Hillf Danton 2013-03-19 10:01 ` Mel Gorman 2013-03-18 23:58 ` Simon Jeons 2013-03-18 23:58 ` Simon Jeons 2013-03-19 10:12 ` Mel Gorman 2013-03-19 10:12 ` Mel Gorman 2013-03-19 3:08 ` Simon Jeons 2013-03-19 3:08 ` Simon Jeons 2013-03-19 8:23 ` Michal Hocko 2013-03-19 8:23 ` Michal Hocko 2013-03-19 10:14 ` Mel Gorman 2013-03-19 10:14 ` Mel Gorman 2013-03-19 10:26 ` Simon Jeons 2013-03-19 10:26 ` Simon Jeons 2013-03-19 11:01 ` Mel Gorman 2013-03-19 11:01 ` Mel Gorman 2013-03-21 14:54 ` Michal Hocko 2013-03-21 14:54 ` Michal Hocko 2013-03-21 15:26 ` Mel Gorman 2013-03-21 15:26 ` Mel Gorman 2013-03-21 15:38 ` Michal Hocko 2013-03-21 15:38 ` Michal Hocko 2013-03-17 13:04 ` [PATCH 04/10] mm: vmscan: Decide whether to compact the pgdat based on reclaim progress Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-18 11:11 ` Wanpeng Li 2013-03-18 11:11 ` Wanpeng Li 2013-03-19 10:19 ` Mel Gorman 2013-03-19 10:19 ` Mel Gorman 2013-03-18 11:35 ` Hillf Danton 2013-03-18 11:35 ` Hillf Danton 2013-03-19 10:27 ` Mel Gorman 2013-03-19 10:27 ` Mel Gorman 2013-03-21 15:32 ` Michal Hocko 2013-03-21 15:32 ` Michal Hocko 2013-03-21 15:47 ` Mel Gorman 2013-03-21 15:47 ` Mel Gorman 2013-03-21 15:50 ` Michal Hocko 2013-03-21 15:50 ` Michal Hocko 2013-03-17 13:04 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-21 1:20 ` Rik van Riel 2013-03-21 1:20 ` Rik van Riel 2013-03-21 10:12 ` Mel Gorman 2013-03-21 10:12 ` Mel Gorman 2013-03-21 12:30 ` Rik van Riel 2013-03-21 12:30 ` Rik van Riel 2013-03-21 15:48 ` Michal Hocko 2013-03-21 15:48 ` Michal Hocko 2013-03-17 13:04 ` [PATCH 06/10] mm: vmscan: Have kswapd writeback pages based on dirty pages encountered, not priority Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:42 ` Andi Kleen 2013-03-17 14:42 ` Andi Kleen 2013-03-17 15:11 ` Mel Gorman 2013-03-17 15:11 ` Mel Gorman 2013-03-21 17:53 ` Rik van Riel 2013-03-21 17:53 ` Rik van Riel 2013-03-21 18:15 ` Mel Gorman 2013-03-21 18:15 ` Mel Gorman 2013-03-21 18:21 ` Rik van Riel 2013-03-21 18:21 ` Rik van Riel 2013-03-18 11:08 ` Wanpeng Li 2013-03-18 11:08 ` Wanpeng Li 2013-03-19 10:35 ` Mel Gorman 2013-03-19 10:35 ` Mel Gorman 2013-03-17 13:04 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:49 ` Andi Kleen 2013-03-17 14:49 ` Andi Kleen 2013-03-17 15:19 ` Mel Gorman 2013-03-17 15:19 ` Mel Gorman 2013-03-17 15:40 ` Andi Kleen 2013-03-17 15:40 ` Andi Kleen 2013-03-19 11:06 ` Mel Gorman 2013-03-19 11:06 ` Mel Gorman 2013-03-18 11:37 ` Simon Jeons 2013-03-18 11:37 ` Simon Jeons 2013-03-19 10:57 ` Mel Gorman 2013-03-19 10:57 ` Mel Gorman 2013-03-18 11:58 ` Wanpeng Li 2013-03-19 10:58 ` Mel Gorman 2013-03-19 10:58 ` Mel Gorman 2013-03-18 11:58 ` Wanpeng Li 2013-03-21 16:32 ` [PATCH 07/10 -v2r1] " Michal Hocko 2013-03-21 16:32 ` Michal Hocko 2013-03-21 18:42 ` [PATCH 07/10] " Rik van Riel 2013-03-21 18:42 ` Rik van Riel 2013-03-22 8:27 ` Mel Gorman 2013-03-22 8:27 ` Mel Gorman 2013-03-17 13:04 ` [PATCH 08/10] mm: vmscan: Have kswapd shrink slab only once per priority Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:53 ` Andi Kleen 2013-03-17 14:53 ` Andi Kleen 2013-03-21 16:47 ` Michal Hocko 2013-03-21 16:47 ` Michal Hocko 2013-03-21 19:47 ` Rik van Riel 2013-03-21 19:47 ` Rik van Riel 2013-04-09 6:53 ` Joonsoo Kim 2013-04-09 6:53 ` Joonsoo Kim 2013-04-09 8:41 ` Simon Jeons 2013-04-09 8:41 ` Simon Jeons 2013-04-09 11:13 ` Mel Gorman 2013-04-09 11:13 ` Mel Gorman 2013-04-10 1:07 ` Dave Chinner 2013-04-10 1:07 ` Dave Chinner 2013-04-10 5:23 ` Joonsoo Kim 2013-04-10 5:23 ` Joonsoo Kim 2013-04-11 9:53 ` Mel Gorman 2013-04-11 9:53 ` Mel Gorman 2013-04-10 5:21 ` Joonsoo Kim 2013-04-10 5:21 ` Joonsoo Kim 2013-04-11 10:01 ` Mel Gorman 2013-04-11 10:01 ` Mel Gorman 2013-04-11 10:29 ` Ric Mason 2013-04-11 10:29 ` Ric Mason 2013-03-17 13:04 ` [PATCH 09/10] mm: vmscan: Check if kswapd should writepage " Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-21 16:58 ` Michal Hocko 2013-03-21 16:58 ` Michal Hocko 2013-03-21 18:07 ` Mel Gorman 2013-03-21 18:07 ` Mel Gorman 2013-03-21 19:52 ` Rik van Riel 2013-03-21 19:52 ` Rik van Riel 2013-03-17 13:04 ` [PATCH 10/10] mm: vmscan: Move logic from balance_pgdat() to kswapd_shrink_zone() Mel Gorman 2013-03-17 13:04 ` Mel Gorman 2013-03-17 14:55 ` Andi Kleen 2013-03-17 14:55 ` Andi Kleen 2013-03-17 15:25 ` Mel Gorman 2013-03-17 15:25 ` Mel Gorman 2013-03-21 17:18 ` Michal Hocko 2013-03-21 17:18 ` Michal Hocko 2013-03-21 18:13 ` Mel Gorman 2013-03-21 18:13 ` Mel Gorman 2013-03-21 10:44 ` [RFC PATCH 0/8] Reduce system disruption due to kswapd Damien Wyart 2013-03-21 10:54 ` Zlatko Calusic 2013-03-21 11:48 ` Mel Gorman 2013-03-21 11:20 ` Mel Gorman 2013-03-22 14:37 ` Mel Gorman 2013-03-22 14:37 ` Mel Gorman 2013-03-24 19:00 ` Jiri Slaby 2013-03-24 19:00 ` Jiri Slaby 2013-03-25 8:17 ` Michal Hocko 2013-03-25 8:17 ` Michal Hocko 2013-04-09 11:06 [PATCH 0/10] Reduce system disruption due to kswapd V2 Mel Gorman 2013-04-09 11:06 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman 2013-04-09 11:06 ` Mel Gorman 2013-04-09 13:27 ` Michal Hocko 2013-04-09 13:27 ` Michal Hocko 2013-04-10 6:47 ` Kamezawa Hiroyuki 2013-04-10 6:47 ` Kamezawa Hiroyuki 2013-04-11 19:57 [PATCH 0/10] Reduce system disruption due to kswapd V3 Mel Gorman 2013-04-11 19:57 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman 2013-04-11 19:57 ` Mel Gorman
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