mm: compaction: add /proc trigger for memory compaction
Add 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@csn.ul.ie> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -19,6 +19,7 @@ files can be found in mm/swap.c.
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Currently, these files are in /proc/sys/vm:
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Currently, these files are in /proc/sys/vm:
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- block_dump
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- block_dump
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- compact_memory
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- dirty_background_bytes
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- dirty_background_bytes
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- dirty_background_ratio
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- dirty_background_ratio
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- dirty_bytes
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- dirty_bytes
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@ -64,6 +65,15 @@ information on block I/O debugging is in Documentation/laptops/laptop-mode.txt.
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==============================================================
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==============================================================
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compact_memory
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Available only when CONFIG_COMPACTION is set. When 1 is written to the file,
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all zones are compacted such that free memory is available in contiguous
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blocks where possible. This can be important for example in the allocation of
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huge pages although processes will also directly compact memory as required.
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==============================================================
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dirty_background_bytes
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dirty_background_bytes
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Contains the amount of dirty memory at which the pdflush background writeback
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Contains the amount of dirty memory at which the pdflush background writeback
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@ -6,4 +6,10 @@
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#define COMPACT_PARTIAL 1
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#define COMPACT_PARTIAL 1
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#define COMPACT_COMPLETE 2
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#define COMPACT_COMPLETE 2
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#ifdef CONFIG_COMPACTION
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extern int sysctl_compact_memory;
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extern int sysctl_compaction_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *length, loff_t *ppos);
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#endif /* CONFIG_COMPACTION */
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#endif /* _LINUX_COMPACTION_H */
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#endif /* _LINUX_COMPACTION_H */
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@ -37,6 +37,7 @@
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#include <linux/highuid.h>
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#include <linux/highuid.h>
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#include <linux/writeback.h>
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#include <linux/writeback.h>
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#include <linux/ratelimit.h>
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#include <linux/ratelimit.h>
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#include <linux/compaction.h>
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#include <linux/hugetlb.h>
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#include <linux/hugetlb.h>
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#include <linux/initrd.h>
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#include <linux/initrd.h>
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#include <linux/key.h>
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#include <linux/key.h>
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@ -1121,6 +1122,15 @@ static struct ctl_table vm_table[] = {
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.mode = 0644,
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.mode = 0644,
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.proc_handler = drop_caches_sysctl_handler,
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.proc_handler = drop_caches_sysctl_handler,
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},
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},
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#ifdef CONFIG_COMPACTION
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{
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.procname = "compact_memory",
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.data = &sysctl_compact_memory,
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.maxlen = sizeof(int),
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.mode = 0200,
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.proc_handler = sysctl_compaction_handler,
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},
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#endif /* CONFIG_COMPACTION */
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{
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{
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.procname = "min_free_kbytes",
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.procname = "min_free_kbytes",
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.data = &min_free_kbytes,
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.data = &min_free_kbytes,
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@ -12,6 +12,7 @@
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#include <linux/compaction.h>
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#include <linux/compaction.h>
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#include <linux/mm_inline.h>
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#include <linux/mm_inline.h>
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#include <linux/backing-dev.h>
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#include <linux/backing-dev.h>
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#include <linux/sysctl.h>
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#include "internal.h"
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#include "internal.h"
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/*
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/*
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@ -391,3 +392,64 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
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return ret;
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return ret;
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}
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}
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/* Compact all zones within a node */
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static int compact_node(int nid)
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{
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int zoneid;
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pg_data_t *pgdat;
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struct zone *zone;
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if (nid < 0 || nid >= nr_node_ids || !node_online(nid))
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return -EINVAL;
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pgdat = NODE_DATA(nid);
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/* Flush pending updates to the LRU lists */
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lru_add_drain_all();
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for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
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struct compact_control cc = {
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.nr_freepages = 0,
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.nr_migratepages = 0,
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};
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zone = &pgdat->node_zones[zoneid];
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if (!populated_zone(zone))
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continue;
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cc.zone = zone;
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INIT_LIST_HEAD(&cc.freepages);
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INIT_LIST_HEAD(&cc.migratepages);
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compact_zone(zone, &cc);
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VM_BUG_ON(!list_empty(&cc.freepages));
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VM_BUG_ON(!list_empty(&cc.migratepages));
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}
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return 0;
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}
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/* Compact all nodes in the system */
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static int compact_nodes(void)
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{
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int nid;
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for_each_online_node(nid)
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compact_node(nid);
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return COMPACT_COMPLETE;
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}
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/* The written value is actually unused, all memory is compacted */
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int sysctl_compact_memory;
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/* This is the entry point for compacting all nodes via /proc/sys/vm */
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int sysctl_compaction_handler(struct ctl_table *table, int write,
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void __user *buffer, size_t *length, loff_t *ppos)
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{
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if (write)
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return compact_nodes();
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return 0;
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}
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