aboutsummaryrefslogtreecommitdiffstats
path: root/include/linux/compaction.h
diff options
context:
space:
mode:
authorMel Gorman <mel@csn.ul.ie>2010-05-24 17:32:31 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2010-05-25 11:06:59 -0400
commit5e7719058079a1423ccce56148b0aaa56b2df821 (patch)
tree3666cb3d5540dcaa3d8e7df8c293a0ad603a181c /include/linux/compaction.h
parent56de7263fcf3eb10c8dcdf8d59a9cec831795f3f (diff)
mm: compaction: add a tunable that decides when memory should be compacted and when it should be reclaimed
The kernel applies some heuristics when deciding if memory should be compacted or reclaimed to satisfy a high-order allocation. One of these is based on the fragmentation. If the index is below 500, memory will not be compacted. This choice is arbitrary and not based on data. To help optimise the system and set a sensible default for this value, this patch adds a sysctl extfrag_threshold. The kernel will only compact memory if the fragmentation index is above the extfrag_threshold. [randy.dunlap@oracle.com: Fix build errors when proc fs is not configured] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/compaction.h')
-rw-r--r--include/linux/compaction.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index eed40ec4280b..3719325c6091 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -15,6 +15,9 @@
15extern int sysctl_compact_memory; 15extern int sysctl_compact_memory;
16extern int sysctl_compaction_handler(struct ctl_table *table, int write, 16extern int sysctl_compaction_handler(struct ctl_table *table, int write,
17 void __user *buffer, size_t *length, loff_t *ppos); 17 void __user *buffer, size_t *length, loff_t *ppos);
18extern int sysctl_extfrag_threshold;
19extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
20 void __user *buffer, size_t *length, loff_t *ppos);
18 21
19extern int fragmentation_index(struct zone *zone, unsigned int order); 22extern int fragmentation_index(struct zone *zone, unsigned int order);
20extern unsigned long try_to_compact_pages(struct zonelist *zonelist, 23extern unsigned long try_to_compact_pages(struct zonelist *zonelist,