blkio: Core implementation of throttle policy

o Actual implementation of throttling policy in block layer. Currently it
  implements READ and WRITE bytes per second throttling logic. IOPS throttling
  comes in later patches.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index ca83a97c971..10a0c291b55 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -130,6 +130,8 @@ enum rq_flag_bits {
         /* bio only flags */
         __REQ_UNPLUG,           /* unplug the immediately after submission */
         __REQ_RAHEAD,           /* read ahead, can fail anytime */
+        __REQ_THROTTLED,        /* This bio has already been subjected to
+                                 * throttling rules. Don't do it again. */
 
         /* request only flags */
         __REQ_SORTED,           /* elevator knows about this request */
@@ -172,6 +174,7 @@ enum rq_flag_bits {
 
 #define REQ_UNPLUG              (1 << __REQ_UNPLUG)
 #define REQ_RAHEAD              (1 << __REQ_RAHEAD)
+#define REQ_THROTTLED           (1 << __REQ_THROTTLED)
 
 #define REQ_SORTED              (1 << __REQ_SORTED)
 #define REQ_SOFTBARRIER         (1 << __REQ_SOFTBARRIER)