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authorMike Snitzer <snitzer@redhat.com>2015-07-16 21:48:55 -0400
committerMike Snitzer <snitzer@redhat.com>2015-07-16 22:32:08 -0400
commit665022d72f9b5762f21b5ea02fa0503d04802849 (patch)
treed7760993f35eac82be5f165d385b3f05fb1f4552 /drivers
parente782eff591bca2d96bac30ab5d1cfa4ccd3b0f86 (diff)
downloadlinux-665022d72f9b5762f21b5ea02fa0503d04802849.tar.gz
dm cache: avoid calls to prealloc_free_structs() if possible
If no work was performed then prealloc_data_structs() wasn't ever called
so there isn't any need to call prealloc_free_structs().

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/md/dm-cache-target.c15
1 files changed, 12 insertions, 3 deletions
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index 408dd276d6c9..b680da5d7b93 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -1946,6 +1946,7 @@ static int commit_if_needed(struct cache *cache)
 
 static void process_deferred_bios(struct cache *cache)
 {
+	bool prealloc_used = false;
 	unsigned long flags;
 	struct bio_list bios;
 	struct bio *bio;
@@ -1980,13 +1981,16 @@ static void process_deferred_bios(struct cache *cache)
 			process_discard_bio(cache, &structs, bio);
 		else
 			process_bio(cache, &structs, bio);
+		prealloc_used = true;
 	}
 
-	prealloc_free_structs(cache, &structs);
+	if (prealloc_used)
+		prealloc_free_structs(cache, &structs);
 }
 
 static void process_deferred_cells(struct cache *cache)
 {
+	bool prealloc_used = false;
 	unsigned long flags;
 	struct dm_bio_prison_cell *cell, *tmp;
 	struct list_head cells;
@@ -2014,9 +2018,11 @@ static void process_deferred_cells(struct cache *cache)
 		}
 
 		process_cell(cache, &structs, cell);
+		prealloc_used = true;
 	}
 
-	prealloc_free_structs(cache, &structs);
+	if (prealloc_used)
+		prealloc_free_structs(cache, &structs);
 }
 
 static void process_deferred_flush_bios(struct cache *cache, bool submit_bios)
@@ -2061,6 +2067,7 @@ static void process_deferred_writethrough_bios(struct cache *cache)
 
 static void writeback_some_dirty_blocks(struct cache *cache)
 {
+	bool prealloc_used = false;
 	dm_oblock_t oblock;
 	dm_cblock_t cblock;
 	struct prealloc structs;
@@ -2080,9 +2087,11 @@ static void writeback_some_dirty_blocks(struct cache *cache)
 		}
 
 		writeback(cache, &structs, oblock, cblock, old_ocell);
+		prealloc_used = true;
 	}
 
-	prealloc_free_structs(cache, &structs);
+	if (prealloc_used)
+		prealloc_free_structs(cache, &structs);
 }
 
 /*----------------------------------------------------------------