[PATCHv2 1/3] zpool: add compaction api

[Vitaly Wool <vitalywool@xxxxxxxxx>]

This patch adds two functions to the zpool API: zpool_compact()
and zpool_get_num_compacted(). The former triggers compaction for
the underlying allocator and the latter retrieves the number of
pages migrated due to compaction for the whole time of this pool's
existence.

Signed-off-by: Vitaly Wool <vitalywool@xxxxxxxxx>

---
 include/linux/zpool.h |  9 +++++++++
 mm/zpool.c            | 23 +++++++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 42f8ec9..be1ed58 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -58,6 +58,10 @@ void *zpool_map_handle(struct zpool *pool, unsigned long handle,
 
 void zpool_unmap_handle(struct zpool *pool, unsigned long handle);
 
+unsigned long zpool_compact(struct zpool *pool);
+
+unsigned long zpool_get_num_compacted(struct zpool *pool);
+
 u64 zpool_get_total_size(struct zpool *pool);
 
 
@@ -72,6 +76,8 @@ u64 zpool_get_total_size(struct zpool *pool);
  * @shrink:	shrink the pool.
  * @map:	map a handle.
  * @unmap:	unmap a handle.
+ * @compact:	try to run compaction over a pool
+ * @get_num_compacted:	get amount of compacted pages for a pool
  * @total_size:	get total size of a pool.
  *
  * This is created by a zpool implementation and registered
@@ -98,6 +104,9 @@ struct zpool_driver {
 				enum zpool_mapmode mm);
 	void (*unmap)(void *pool, unsigned long handle);
 
+	unsigned long (*compact)(void *pool);
+	unsigned long (*get_num_compacted)(void *pool);
+
 	u64 (*total_size)(void *pool);
 };
 
diff --git a/mm/zpool.c b/mm/zpool.c
index 8f670d3..e469a66 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -340,6 +340,29 @@ void zpool_unmap_handle(struct zpool *zpool, unsigned long handle)
 	zpool->driver->unmap(zpool->pool, handle);
 }
 
+ /**
+ * zpool_compact() - try to run compaction over zpool
+ * @pool       The zpool to compact
+ *
+ * Returns: the number of migrated pages
+ */
+unsigned long zpool_compact(struct zpool *zpool)
+{
+	return zpool->driver->compact(zpool->pool);
+}
+
+
+/**
+ * zpool_get_num_compacted() - get the number of migrated/compacted pages
+ * @stats	stats to fill in
+ *
+ * Returns: the total number of migrated pages for the pool
+ */
+unsigned long zpool_get_num_compacted(struct zpool *zpool)
+{
+	zpool->driver->get_num_compacted(zpool->pool);
+}
+
 /**
  * zpool_get_total_size() - The total size of the pool
  * @pool	The zpool to check
-- 
1.9.1

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