dm crypt: increase mempool reserve to better support swapping

Mikulas Patocka · snitm · commit 0a83df6c8cac · 2016-08-15T09:23:14.000-04:00
Increase mempool size from 16 to 64 entries.  This increase improves
swap on dm-crypt performance.

When swapping to dm-crypt, all available memory is temporarily exhausted
and dm-crypt can only use the mempool reserve.

Signed-off-by: Mikulas Patocka &lt;mpatocka@redhat.com&gt;
Signed-off-by: Mike Snitzer &lt;snitzer@redhat.com&gt;
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
@@ -181,7 +181,7 @@ struct crypt_config {
 	u8 key[0];
 };
 
-#define MIN_IOS        16
+#define MIN_IOS        64
 
 static void clone_init(struct dm_crypt_io *, struct bio *);
 static void kcryptd_queue_crypt(struct dm_crypt_io *io);
