On Fri, 19 Feb 2010 14:16:41 +0000
Mel Gorman <mel@xxxxxxxxx> wrote:
> On Fri, Feb 19, 2010 at 09:43:26AM +0900, KAMEZAWA Hiroyuki wrote:
> > On Thu, 18 Feb 2010 18:02:39 +0000
> > Mel Gorman <mel@xxxxxxxxx> 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 <mel@xxxxxxxxx>
> > > Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> >
> > Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> >
> > Nitpick:
> > Hmm.. Is this necessary if we have per-node trigger in sysfs ?
> >
>
> What does !NUMA do?
>
.... I missed that. please ignore my comment.
(And I missed that we already have famous trigger as drop_caches in sysctl..)
Thanks,
-Kame
> > 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 <linux/ftrace.h>
> > > #include <linux/slow-work.h>
> > > #include <linux/perf_event.h>
> > > +#include <linux/compaction.h>
> > >
> > > #include <asm/uaccess.h>
> > > #include <asm/processor.h>
> > > @@ -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 <linux/migrate.h>
> > > #include <linux/compaction.h>
> > > #include <linux/mm_inline.h>
> > > +#include <linux/sysctl.h>
> > > #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
> > >
> > > --
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> > >
> >
>
> --
> Mel Gorman
> Part-time Phd Student Linux Technology Center
> University of Limerick IBM Dublin Software Lab
>
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