Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753748Ab0BSOQ6 (ORCPT ); Fri, 19 Feb 2010 09:16:58 -0500 Received: from gir.skynet.ie ([193.1.99.77]:56755 "EHLO gir.skynet.ie" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751569Ab0BSOQ4 (ORCPT ); Fri, 19 Feb 2010 09:16:56 -0500 Date: Fri, 19 Feb 2010 14:16:41 +0000 From: Mel Gorman To: KAMEZAWA Hiroyuki Cc: Andrea Arcangeli , Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 09/12] Add /proc trigger for memory compaction Message-ID: <20100219141641.GJ30258@csn.ul.ie> References: <1266516162-14154-1-git-send-email-mel@csn.ul.ie> <1266516162-14154-10-git-send-email-mel@csn.ul.ie> <20100219094326.e725f8e8.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20100219094326.e725f8e8.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.17+20080114 (2008-01-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6492 Lines: 205 On Fri, Feb 19, 2010 at 09:43:26AM +0900, KAMEZAWA Hiroyuki wrote: > On Thu, 18 Feb 2010 18:02:39 +0000 > Mel Gorman wrote: > > > This patch adds a proc file /proc/sys/vm/compact_memory. When an arbitrary > > value is written to the file, all zones are compacted. The expected user > > of such a trigger is a job scheduler that prepares the system before the > > target application runs. > > > > Signed-off-by: Mel Gorman > > Acked-by: Rik van Riel > > Reviewed-by: KAMEZAWA Hiroyuki > > Nitpick: > Hmm.. Is this necessary if we have per-node trigger in sysfs ? > What does !NUMA do? > Thanks, > -Kame > > > > --- > > Documentation/sysctl/vm.txt | 11 ++++++++ > > include/linux/compaction.h | 5 +++ > > kernel/sysctl.c | 11 ++++++++ > > mm/compaction.c | 60 +++++++++++++++++++++++++++++++++++++++++++ > > 4 files changed, 87 insertions(+), 0 deletions(-) > > > > diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt > > index fc5790d..92b5b00 100644 > > --- a/Documentation/sysctl/vm.txt > > +++ b/Documentation/sysctl/vm.txt > > @@ -19,6 +19,7 @@ files can be found in mm/swap.c. > > Currently, these files are in /proc/sys/vm: > > > > - block_dump > > +- compact_memory > > - dirty_background_bytes > > - dirty_background_ratio > > - dirty_bytes > > @@ -64,6 +65,16 @@ information on block I/O debugging is in Documentation/laptops/laptop-mode.txt. > > > > ============================================================== > > > > +compact_memory > > + > > +Available only when CONFIG_COMPACTION is set. When an arbitrary value > > +is written to the file, all zones are compacted such that free memory > > +is available in contiguous blocks where possible. This can be important > > +for example in the allocation of huge pages although processes will also > > +directly compact memory as required. > > + > > +============================================================== > > + > > dirty_background_bytes > > > > Contains the amount of dirty memory at which the pdflush background writeback > > diff --git a/include/linux/compaction.h b/include/linux/compaction.h > > index 6201371..facaa3d 100644 > > --- a/include/linux/compaction.h > > +++ b/include/linux/compaction.h > > @@ -5,4 +5,9 @@ > > #define COMPACT_INCOMPLETE 0 > > #define COMPACT_COMPLETE 1 > > > > +#ifdef CONFIG_COMPACTION > > +extern int sysctl_compaction_handler(struct ctl_table *table, int write, > > + void __user *buffer, size_t *length, loff_t *ppos); > > +#endif /* CONFIG_COMPACTION */ > > + > > #endif /* _LINUX_COMPACTION_H */ > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > > index 8a68b24..a02c816 100644 > > --- a/kernel/sysctl.c > > +++ b/kernel/sysctl.c > > @@ -50,6 +50,7 @@ > > #include > > #include > > #include > > +#include > > > > #include > > #include > > @@ -80,6 +81,7 @@ extern int pid_max; > > extern int min_free_kbytes; > > extern int pid_max_min, pid_max_max; > > extern int sysctl_drop_caches; > > +extern int sysctl_compact_memory; > > extern int percpu_pagelist_fraction; > > extern int compat_log; > > extern int latencytop_enabled; > > @@ -1109,6 +1111,15 @@ static struct ctl_table vm_table[] = { > > .mode = 0644, > > .proc_handler = drop_caches_sysctl_handler, > > }, > > +#ifdef CONFIG_COMPACTION > > + { > > + .procname = "compact_memory", > > + .data = &sysctl_compact_memory, > > + .maxlen = sizeof(int), > > + .mode = 0200, > > + .proc_handler = sysctl_compaction_handler, > > + }, > > +#endif /* CONFIG_COMPACTION */ > > { > > .procname = "min_free_kbytes", > > .data = &min_free_kbytes, > > diff --git a/mm/compaction.c b/mm/compaction.c > > index 14ba0ac..22f223f 100644 > > --- a/mm/compaction.c > > +++ b/mm/compaction.c > > @@ -11,6 +11,7 @@ > > #include > > #include > > #include > > +#include > > #include "internal.h" > > > > /* > > @@ -345,3 +346,62 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) > > return ret; > > } > > > > +/* Compact all zones within a node */ > > +static int compact_node(int nid) > > +{ > > + int zoneid; > > + pg_data_t *pgdat; > > + struct zone *zone; > > + > > + if (nid < 0 || nid > nr_node_ids || !node_online(nid)) > > + return -EINVAL; > > + pgdat = NODE_DATA(nid); > > + > > + /* Flush pending updates to the LRU lists */ > > + lru_add_drain_all(); > > + > > + for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { > > + struct compact_control cc; > > + > > + zone = &pgdat->node_zones[zoneid]; > > + if (!populated_zone(zone)) > > + continue; > > + > > + cc.nr_freepages = 0; > > + cc.nr_migratepages = 0; > > + cc.zone = zone; > > + INIT_LIST_HEAD(&cc.freepages); > > + INIT_LIST_HEAD(&cc.migratepages); > > + > > + compact_zone(zone, &cc); > > + > > + VM_BUG_ON(!list_empty(&cc.freepages)); > > + VM_BUG_ON(!list_empty(&cc.migratepages)); > > + } > > + > > + return 0; > > +} > > + > > +/* Compact all nodes in the system */ > > +static int compact_nodes(void) > > +{ > > + int nid; > > + > > + for_each_online_node(nid) > > + compact_node(nid); > > + > > + return COMPACT_COMPLETE; > > +} > > + > > +/* The written value is actually unused, all memory is compacted */ > > +int sysctl_compact_memory; > > + > > +/* This is the entry point for compacting all nodes via /proc/sys/vm */ > > +int sysctl_compaction_handler(struct ctl_table *table, int write, > > + void __user *buffer, size_t *length, loff_t *ppos) > > +{ > > + if (write) > > + return compact_nodes(); > > + > > + return 0; > > +} > > -- > > 1.6.5 > > > > -- > > 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 > > > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/