[BLOCK] mark some block/ variables cons
the patch below marks various read-only variables in block/* as const,
so that gcc can optimize the use of them; eg gcc will replace the use by
the value directly now and will even remove the memory usage of these.
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/block/deadline-iosched.c b/block/deadline-iosched.c
index 9cbec09..27e494b 100644
--- a/block/deadline-iosched.c
+++ b/block/deadline-iosched.c
@@ -19,10 +19,10 @@
/*
* See Documentation/block/deadline-iosched.txt
*/
-static int read_expire = HZ / 2; /* max time before a read is submitted. */
-static int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
-static int writes_starved = 2; /* max times reads can starve a write */
-static int fifo_batch = 16; /* # of sequential requests treated as one
+static const int read_expire = HZ / 2; /* max time before a read is submitted. */
+static const int write_expire = 5 * HZ; /* ditto for writes, these limits are SOFT! */
+static const int writes_starved = 2; /* max times reads can starve a write */
+static const int fifo_batch = 16; /* # of sequential requests treated as one
by the above parameters. For throughput. */
static const int deadline_hash_shift = 5;