[PATCH 2/9] block: add support for write hints in a bio

[Jens Axboe]

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_LIFE_*
life time hint.

Ensure that we don't merge requests that have different life time
hints assigned to them.

Reviewed-by: Martin K. Petersen 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Jens Axboe 
---
 block/blk-merge.c | 16 
 fs/inode.c|  9 +
 include/linux/blk_types.h | 31 +++
 include/linux/fs.h|  2 ++
 4 files changed, 58 insertions(+)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index 5df13041b851..be1e955db75e 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -673,6 +673,14 @@ static struct request *attempt_merge(struct request_queue 
*q,
return NULL;
 
/*
+* Don't allow merge of different write hints, or for a hint with
+* non-hint 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
@@ -791,6 +799,14 @@ 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 write hints, or for a hint with
+* non-hint IO.
+*/
+   if ((rq->cmd_flags & REQ_WRITE_LIFE_MASK) !=
+   (bio->bi_opf & REQ_WRITE_LIFE_MASK))
+   return false;
+
return true;
 }
 
diff --git a/fs/inode.c b/fs/inode.c
index defb015a2c6d..66cc431c9a96 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2131,3 +2131,12 @@ void inode_set_write_hint(struct inode *inode, enum 
rw_hint hint)
inode_unlock(inode);
}
 }
+
+/*
+ * Returns block write hint mask for the inode
+ */
+unsigned int inode_hint_to_opf(struct inode *inode)
+{
+   return write_hint_to_opf(inode_write_hint(inode));
+}
+EXPORT_SYMBOL(inode_hint_to_opf);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index e210da6d14b8..0d44dce19d9f 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -7,6 +7,7 @@
 
 #include 
 #include 
+#include 
 
 struct bio_set;
 struct bio;
@@ -223,6 +224,10 @@ enum req_flag_bits {
__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 */
 
@@ -244,6 +249,13 @@ enum req_flag_bits {
 #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)
 #define REQ_NOWAIT (1ULL << __REQ_NOWAIT)
 
@@ -335,4 +347,23 @@ struct blk_rq_stat {
u64 batch;
 };
 
+static inline unsigned int write_hint_to_opf(enum rw_hint hint)
+{
+   return hint << __REQ_WRITE_HINT_SHIFT;
+}
+
+/*
+ * Don't let drivers see WRITE_LIFE_NOT_SET, return NONE for that
+ */
+static inline enum rw_hint opf_to_write_hint(unsigned int opf)
+{
+   enum rw_hint ret;
+
+   ret = (opf & REQ_WRITE_LIFE_MASK) >> __REQ_WRITE_HINT_SHIFT;
+   if (ret == WRITE_LIFE_NOT_SET)
+   ret = WRITE_LIFE_NONE;
+
+   return ret;
+}
+
 #endif /* __LINUX_BLK_TYPES_H */
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0ef5d110d2bc..86888a6ccad1 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1912,6 +1912,8 @@ static inline bool HAS_UNMAPPED_ID(struct inode *inode)
return !uid_valid(inode->i_uid) || !gid_valid(inode->i_gid);
 }
 
+extern unsigned int inode_hint_to_opf(struct inode *inode);
+
 static inline unsigned int write_hint_to_mask(enum rw_hint hint,
  unsigned int shift)
 {
-- 
2.7.4

Re: [PATCH 2/9] block: add support for write hints in a bio

[Christoph Hellwig]

Looks fine for now:

Reviewed-by: Christoph Hellwig 

(although I suspect we'll eventually move to a hints field
separate from the REQ_* flags).

[PATCH 2/9] block: add support for write hints in a bio

[Jens Axboe]

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_LIFE_*
life time hint.

Ensure that we don't merge requests that have different life time
hints assigned to them.

Signed-off-by: Jens Axboe 
---
 block/blk-merge.c | 16 
 include/linux/blk_types.h | 31 +++
 2 files changed, 47 insertions(+)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index cea544ec5d96..17cd0c3f872d 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -670,6 +670,14 @@ 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
@@ -788,6 +796,14 @@ 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 e210da6d14b8..4ce71298e45b 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -7,6 +7,7 @@
 
 #include 
 #include 
+#include 
 
 struct bio_set;
 struct bio;
@@ -223,6 +224,10 @@ enum req_flag_bits {
__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 */
 
@@ -244,6 +249,13 @@ enum req_flag_bits {
 #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)
 #define REQ_NOWAIT (1ULL << __REQ_NOWAIT)
 
@@ -335,4 +347,23 @@ struct blk_rq_stat {
u64 batch;
 };
 
+static inline unsigned int write_hint_to_opf(enum rw_hint hint)
+{
+   return hint << __REQ_WRITE_HINT_SHIFT;
+}
+
+/*
+ * Don't let drivers see WRITE_LIFE_NOT_SET, return NONE for that
+ */
+static inline enum rw_hint opf_to_write_hint(unsigned int opf)
+{
+   enum rw_hint ret;
+
+   ret = (opf & REQ_WRITE_LIFE_MASK) >> __REQ_WRITE_HINT_SHIFT;
+   if (ret == WRITE_LIFE_NOT_SET)
+   ret = WRITE_LIFE_NONE;
+
+   return ret;
+}
+
 #endif /* __LINUX_BLK_TYPES_H */
-- 
2.7.4

[PATCH 2/9] block: add support for write hints in a bio

[Jens Axboe]

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_LIFE_*
life time hint.

Ensure that we don't merge requests that have different life time
hints assigned to them.

Signed-off-by: Jens Axboe 
---
 block/blk-merge.c | 16 
 include/linux/blk_types.h | 20 
 2 files changed, 36 insertions(+)

diff --git a/block/blk-merge.c b/block/blk-merge.c
index cea544ec5d96..17cd0c3f872d 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -670,6 +670,14 @@ 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
@@ -788,6 +796,14 @@ 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 dcd45b15a3a5..fde216924aa3 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -7,6 +7,7 @@
 
 #include 
 #include 
+#include 
 
 struct bio_set;
 struct bio;
@@ -220,6 +221,9 @@ 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 */
@@ -240,6 +244,12 @@ 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)
 
@@ -331,4 +341,14 @@ struct blk_rq_stat {
u64 batch;
 };
 
+static inline unsigned int write_hint_to_opf(enum rw_hint hint)
+{
+   return hint << __REQ_WRITE_HINT_SHIFT;
+}
+
+static inline enum rw_hint opf_to_write_hint(unsigned int opf)
+{
+   return (opf & REQ_WRITE_LIFE_MASK) >> __REQ_WRITE_HINT_SHIFT;
+}
+
 #endif /* __LINUX_BLK_TYPES_H */
-- 
2.7.4