This adds a new request flag, REQ_BG, that callers can use to tell
the block layer that this is background (non-urgent) IO.
Signed-off-by: Jens Axboe <ax...@fb.com>
---
include/linux/blk_types.h | 4 +++-
include/linux/fs.h | 3 +++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 436f43f87da9..be4409b6ae4f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -155,6 +155,7 @@ enum rq_flag_bits {
__REQ_INTEGRITY, /* I/O includes block integrity payload */
__REQ_FUA, /* forced unit access */
__REQ_PREFLUSH, /* request for cache flush */
+ __REQ_BG, /* background activity */
/* bio only flags */
__REQ_RAHEAD, /* read ahead, can fail anytime */
@@ -198,7 +199,7 @@ enum rq_flag_bits {
(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
#define REQ_COMMON_MASK \
(REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | REQ_NOIDLE | \
- REQ_PREFLUSH | REQ_FUA | REQ_INTEGRITY | REQ_NOMERGE)
+ REQ_PREFLUSH | REQ_FUA | REQ_INTEGRITY | REQ_NOMERGE | REQ_BG)
#define REQ_CLONE_MASK REQ_COMMON_MASK
/* This mask is used for both bio and request merge checking */
@@ -223,6 +224,7 @@ enum rq_flag_bits {
#define REQ_COPY_USER (1ULL << __REQ_COPY_USER)
#define REQ_PREFLUSH (1ULL << __REQ_PREFLUSH)
#define REQ_FLUSH_SEQ (1ULL << __REQ_FLUSH_SEQ)
+#define REQ_BG (1ULL << __REQ_BG)
#define REQ_IO_STAT (1ULL << __REQ_IO_STAT)
#define REQ_MIXED_MERGE (1ULL << __REQ_MIXED_MERGE)
#define REQ_PM (1ULL << __REQ_PM)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3523bf62f328..5a5f567c416a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -189,6 +189,8 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t
offset,
* WRITE_FLUSH_FUA Combination of WRITE_FLUSH and FUA. The IO is preceded
* by a cache flush and data is guaranteed to be on
* non-volatile media on completion.
+ * WRITE_BG Background write. This is for background activity like
+ * the periodic flush and background threshold writeback
*
*/
#define RW_MASK REQ_OP_WRITE
@@ -202,6 +204,7 @@ typedef int (dio_iodone_t)(struct kiocb *iocb, loff_t
offset,
#define WRITE_FLUSH (REQ_SYNC | REQ_NOIDLE | REQ_PREFLUSH)
#define WRITE_FUA (REQ_SYNC | REQ_NOIDLE | REQ_FUA)
#define WRITE_FLUSH_FUA (REQ_SYNC | REQ_NOIDLE | REQ_PREFLUSH |
REQ_FUA)
+#define WRITE_BG (REQ_NOIDLE | REQ_BG)
/*
* Attribute flags. These should be or-ed together to figure out what
--
2.7.4
