No functional changes in this patch, we just set aside 3 bits
in the bio/request flags, which can be used to hold a WRITE_HINT_*
life time hint.
Ensure that we don't merge requests that have different life time
hints assigned to them.
Signed-off-by: Jens Axboe <ax...@kernel.dk>
---
block/blk-merge.c | 16 ++++++++++++++++
include/linux/blk_types.h | 15 +++++++++++++++
2 files changed, 31 insertions(+)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 3990ae406341..7d299df3b12b 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -693,6 +693,14 @@ static struct request *attempt_merge(struct request_queue
*q,
return NULL;
/*
+ * Don't allow merge of different streams, or for a stream with
+ * non-stream IO.
+ */
+ if ((req->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (next->cmd_flags & REQ_WRITE_LIFE_MASK))
+ return NULL;
+
+ /*
* If we are allowed to merge, then append bio list
* from next to rq and release next. merge_requests_fn
* will have updated segment counts, update sector
@@ -811,6 +819,14 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
!blk_write_same_mergeable(rq->bio, bio))
return false;
+ /*
+ * Don't allow merge of different streams, or for a stream with
+ * non-stream IO.
+ */
+ if ((rq->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+ (bio->bi_opf & REQ_WRITE_LIFE_MASK))
+ return false;
+
return true;
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 61339bc44400..0dd8d569d52f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -7,6 +7,7 @@
#include <linux/types.h>
#include <linux/bvec.h>
+#include <linux/fs.h>
struct bio_set;
struct bio;
@@ -201,6 +202,9 @@ enum req_flag_bits {
__REQ_PREFLUSH, /* request for cache flush */
__REQ_RAHEAD, /* read ahead, can fail anytime */
__REQ_BACKGROUND, /* background IO */
+ __REQ_WRITE_HINT_SHIFT, /* 3 bits for life time hint */
+ __REQ_WRITE_HINT_PAD1,
+ __REQ_WRITE_HINT_PAD2,
/* command specific flags for REQ_OP_WRITE_ZEROES: */
__REQ_NOUNMAP, /* do not free blocks when zeroing */
@@ -221,6 +225,12 @@ enum req_flag_bits {
#define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH)
#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
#define REQ_BACKGROUND (1ULL << __REQ_BACKGROUND)
+#define REQ_WRITE_SHORT (WRITE_LIFE_SHORT <<
__REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_MEDIUM (WRITE_LIFE_MEDIUM << __REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_LONG (WRITE_LIFE_LONG << __REQ_WRITE_HINT_SHIFT)
+#define REQ_WRITE_EXTREME (WRITE_LIFE_EXTREME << __REQ_WRITE_HINT_SHIFT)
+
+#define REQ_WRITE_LIFE_MASK (0x7 << __REQ_WRITE_HINT_SHIFT)
#define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP)
@@ -312,4 +322,9 @@ struct blk_rq_stat {
u64 batch;
};
+static inline unsigned int write_hint_to_opf(enum rw_hint hint)
+{
+ return hint << __REQ_WRITE_HINT_SHIFT;
+}
+
#endif /* __LINUX_BLK_TYPES_H */
--
2.7.4
