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: Mel Gorman <mel@csn.ul.ie>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: 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>
diff --git a/Documentation/ABI/testing/sysfs-devices-node b/Documentation/ABI/testing/sysfs-devices-node
new file mode 100644
index 0000000..453a210
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-devices-node
@@ -0,0 +1,7 @@
+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
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 057979a..2bdd8a9 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -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 @@
scan_unevictable_register_node(node);
hugetlb_register_node(node);
+
+ compaction_register_node(node);
}
return error;
}
diff --git a/include/linux/compaction.h b/include/linux/compaction.h
index 5723888..ba98cfe 100644
--- a/include/linux/compaction.h
+++ b/include/linux/compaction.h
@@ -12,4 +12,20 @@
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 */
diff --git a/mm/compaction.c b/mm/compaction.c
index 77854fb..f61f779 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -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 @@
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 */