dm space maps: improve performance with inc/dec on ranges of blocks

When we break sharing on btree nodes we typically need to increment
the reference counts to every value held in the node.  This can
cause a lot of repeated calls to the space maps.  Fix this by changing
the interface to the space map inc/dec methods to take ranges of
adjacent blocks to be operated on.

For installations that are using a lot of snapshots this will reduce
cpu overhead of fundamental operations such as provisioning a new block,
or deleting a snapshot, by as much as 10 times.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 4 insertions, 12 deletions

diff --git a/drivers/md/persistent-data/dm-btree-spine.c b/drivers/md/persistent-data/dm-btree-spine.c
index 2061ab865567..f5bd76ed8fe6 100644
--- a/drivers/md/persistent-data/dm-btree-spine.c
+++ b/drivers/md/persistent-data/dm-btree-spine.c
@@ -236,22 +236,14 @@ dm_block_t shadow_root(struct shadow_spine *s)
 	return s->root;
 }
 
-static void le64_inc(void *context, const void *value_le)
+static void le64_inc(void *context, const void *value_le, unsigned count)
 {
-	struct dm_transaction_manager *tm = context;
-	__le64 v_le;
-
-	memcpy(&v_le, value_le, sizeof(v_le));
-	dm_tm_inc(tm, le64_to_cpu(v_le));
+	dm_tm_with_runs(context, value_le, count, dm_tm_inc_range);
 }
 
-static void le64_dec(void *context, const void *value_le)
+static void le64_dec(void *context, const void *value_le, unsigned count)
 {
-	struct dm_transaction_manager *tm = context;
-	__le64 v_le;
-
-	memcpy(&v_le, value_le, sizeof(v_le));
-	dm_tm_dec(tm, le64_to_cpu(v_le));
+	dm_tm_with_runs(context, value_le, count, dm_tm_dec_range);
 }
 
 static int le64_equal(void *context, const void *value1_le, const void *value2_le)