Commit ed4a6d7f authored by Mel Gorman's avatar Mel Gorman Committed by Linus Torvalds
Browse files

mm: compaction: add /sys trigger for per-node memory compaction 



Add a per-node sysfs file called compact.  When the file is written to,
each zone in that node is compacted.  The intention that this would be
used by something like a job scheduler in a batch system before a job
starts so that the job can allocate the maximum number of hugepages
without significant start-up cost.

Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: default avatarChristoph Lameter <cl@linux-foundation.org>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 76ab0f53

Documentation/ABI/testing/sysfs-devices-node

0 → 100644
+7 −0
Original line number Diff line number Diff line 
What:		/sys/devices/system/node/nodeX/compact

Date:		February 2010

Contact:	Mel Gorman <mel@csn.ul.ie>

Description:

		When this file is written to, all memory within that node

		will be compacted. When it completes, memory will be freed

		into blocks which have as many contiguous pages as possible

drivers/base/node.c

+3 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 
#include <linux/memory.h>

#include <linux/node.h>

#include <linux/hugetlb.h>

#include <linux/compaction.h>

#include <linux/cpumask.h>

#include <linux/topology.h>

#include <linux/nodemask.h>
@@ -246,6 +247,8 @@ int register_node(struct node *node, int num, struct node *parent) 
		scan_unevictable_register_node(node);



		hugetlb_register_node(node);



		compaction_register_node(node);

	}

	return error;

}

include/linux/compaction.h

+16 −0
Original line number Diff line number Diff line
@@ -12,4 +12,20 @@ extern int sysctl_compaction_handler(struct ctl_table *table, int write, 
			void __user *buffer, size_t *length, loff_t *ppos);

#endif /* CONFIG_COMPACTION */



#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)

extern int compaction_register_node(struct node *node);

extern void compaction_unregister_node(struct node *node);



#else



static inline int compaction_register_node(struct node *node)

{

	return 0;

}



static inline void compaction_unregister_node(struct node *node)

{

}

#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */



#endif /* _LINUX_COMPACTION_H */

mm/compaction.c

+23 −0
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#include <linux/mm_inline.h>

#include <linux/backing-dev.h>

#include <linux/sysctl.h>

#include <linux/sysfs.h>

#include "internal.h"



/*
@@ -453,3 +454,25 @@ int sysctl_compaction_handler(struct ctl_table *table, int write, 


	return 0;

}



#if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)

ssize_t sysfs_compact_node(struct sys_device *dev,

			struct sysdev_attribute *attr,

			const char *buf, size_t count)

{

	compact_node(dev->id);



	return count;

}

static SYSDEV_ATTR(compact, S_IWUSR, NULL, sysfs_compact_node);



int compaction_register_node(struct node *node)

{

	return sysdev_create_file(&node->sysdev, &attr_compact);

}



void compaction_unregister_node(struct node *node)

{

	return sysdev_remove_file(&node->sysdev, &attr_compact);

}

#endif /* CONFIG_SYSFS && CONFIG_NUMA */

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