Re: [Cluster-devel] [PATCH V14 00/18] block: support multi-page bvec
On Mon, Jan 21, 2019 at 01:43:21AM -0800, Sagi Grimberg wrote: > > > V14: > > - drop patch(patch 4 in V13) for renaming bvec helpers, as suggested by > > Jens > > - use mp_bvec_* as multi-page bvec helper name > > - fix one build issue, which is caused by missing one converion of > > bio_for_each_segment_all in fs/gfs2 > > - fix one 32bit ARCH specific issue caused by segment boundary mask > > overflow > > Hey Ming, > > So is nvme-tcp also affected here? The only point where I see nvme-tcp > can be affected is when initializing a bvec iter using bio_segments() as > everywhere else we use iters which should transparently work.. > > I see that loop was converted, does it mean that nvme-tcp needs to > call something like? > -- > bio_for_each_mp_bvec(bv, bio, iter) > nr_bvecs++; bio_for_each_segment()/bio_segments() still works, just not as efficient as bio_for_each_mp_bvec() given each multi-page bvec(very similar with scatterlist) is returned in each loop. I don't look at nvme-tcp code yet. But if nvme-tcp supports this way, it can benefit from bio_for_each_mp_bvec(). Thanks, Ming
Re: [Cluster-devel] [PATCH V14 00/18] block: support multi-page bvec
V14: - drop patch(patch 4 in V13) for renaming bvec helpers, as suggested by Jens - use mp_bvec_* as multi-page bvec helper name - fix one build issue, which is caused by missing one converion of bio_for_each_segment_all in fs/gfs2 - fix one 32bit ARCH specific issue caused by segment boundary mask overflow Hey Ming, So is nvme-tcp also affected here? The only point where I see nvme-tcp can be affected is when initializing a bvec iter using bio_segments() as everywhere else we use iters which should transparently work.. I see that loop was converted, does it mean that nvme-tcp needs to call something like? -- bio_for_each_mp_bvec(bv, bio, iter) nr_bvecs++; --
Re: [Cluster-devel] [PATCH V14 00/18] block: support multi-page bvec
On Mon, Jan 21, 2019 at 09:38:10AM +0100, Christoph Hellwig wrote: > On Mon, Jan 21, 2019 at 04:37:12PM +0800, Ming Lei wrote: > > On Mon, Jan 21, 2019 at 09:22:46AM +0100, Christoph Hellwig wrote: > > > On Mon, Jan 21, 2019 at 04:17:47PM +0800, Ming Lei wrote: > > > > V14: > > > > - drop patch(patch 4 in V13) for renaming bvec helpers, as > > > > suggested by Jens > > > > - use mp_bvec_* as multi-page bvec helper name > > > > > > WTF? Where is this coming from? mp is just a nightmare of a name, > > > and I also didn't see any comments like that. > > > > You should see the recent discussion in which Jens doesn't agree on > > renaming bvec helper name, so the previous patch of 'block: rename bvec > > helpers' > > Where is that discussion? https://marc.info/?l=linux-next=154777954232109=2 Thanks, Ming
Re: [Cluster-devel] [PATCH V14 00/18] block: support multi-page bvec
On Mon, Jan 21, 2019 at 04:17:47PM +0800, Ming Lei wrote: > V14: > - drop patch(patch 4 in V13) for renaming bvec helpers, as suggested by > Jens > - use mp_bvec_* as multi-page bvec helper name WTF? Where is this coming from? mp is just a nightmare of a name, and I also didn't see any comments like that.
[Cluster-devel] [PATCH V14 17/18] block: kill QUEUE_FLAG_NO_SG_MERGE
Since bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting"),
physical segment number is mainly figured out in blk_queue_split() for
fast path, and the flag of BIO_SEG_VALID is set there too.
Now only blk_recount_segments() and blk_recalc_rq_segments() use this
flag.
Basically blk_recount_segments() is bypassed in fast path given BIO_SEG_VALID
is set in blk_queue_split().
For another user of blk_recalc_rq_segments():
- run in partial completion branch of blk_update_request, which is an unusual
case
- run in blk_cloned_rq_check_limits(), still not a big problem if the flag is
killed
since dm-rq is the only user.
Multi-page bvec is enabled now, not doing S/G merging is rather pointless with
the
current setup of the I/O path, as it isn't going to save you a significant
amount
of cycles.
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
block/blk-merge.c | 31 ++-
block/blk-mq-debugfs.c | 1 -
block/blk-mq.c | 3 ---
drivers/md/dm-table.c | 13 -
include/linux/blkdev.h | 1 -
5 files changed, 6 insertions(+), 43 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 8a498f29636f..b990853f6de7 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -358,8 +358,7 @@ void blk_queue_split(struct request_queue *q, struct bio
**bio)
EXPORT_SYMBOL(blk_queue_split);
static unsigned int __blk_recalc_rq_segments(struct request_queue *q,
-struct bio *bio,
-bool no_sg_merge)
+struct bio *bio)
{
struct bio_vec bv, bvprv = { NULL };
int prev = 0;
@@ -385,13 +384,6 @@ static unsigned int __blk_recalc_rq_segments(struct
request_queue *q,
nr_phys_segs = 0;
for_each_bio(bio) {
bio_for_each_mp_bvec(bv, bio, iter) {
- /*
-* If SG merging is disabled, each bio vector is
-* a segment
-*/
- if (no_sg_merge)
- goto new_segment;
-
if (prev) {
if (seg_size + bv.bv_len
> queue_max_segment_size(q))
@@ -421,27 +413,16 @@ static unsigned int __blk_recalc_rq_segments(struct
request_queue *q,
void blk_recalc_rq_segments(struct request *rq)
{
- bool no_sg_merge = !!test_bit(QUEUE_FLAG_NO_SG_MERGE,
- >q->queue_flags);
-
- rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio,
- no_sg_merge);
+ rq->nr_phys_segments = __blk_recalc_rq_segments(rq->q, rq->bio);
}
void blk_recount_segments(struct request_queue *q, struct bio *bio)
{
- unsigned short seg_cnt = bio_segments(bio);
-
- if (test_bit(QUEUE_FLAG_NO_SG_MERGE, >queue_flags) &&
- (seg_cnt < queue_max_segments(q)))
- bio->bi_phys_segments = seg_cnt;
- else {
- struct bio *nxt = bio->bi_next;
+ struct bio *nxt = bio->bi_next;
- bio->bi_next = NULL;
- bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio, false);
- bio->bi_next = nxt;
- }
+ bio->bi_next = NULL;
+ bio->bi_phys_segments = __blk_recalc_rq_segments(q, bio);
+ bio->bi_next = nxt;
bio_set_flag(bio, BIO_SEG_VALID);
}
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 90d68760af08..2f9a11ef5bad 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -128,7 +128,6 @@ static const char *const blk_queue_flag_name[] = {
QUEUE_FLAG_NAME(SAME_FORCE),
QUEUE_FLAG_NAME(DEAD),
QUEUE_FLAG_NAME(INIT_DONE),
- QUEUE_FLAG_NAME(NO_SG_MERGE),
QUEUE_FLAG_NAME(POLL),
QUEUE_FLAG_NAME(WC),
QUEUE_FLAG_NAME(FUA),
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3ba37b9e15e9..fa45817a7e62 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2829,9 +2829,6 @@ struct request_queue *blk_mq_init_allocated_queue(struct
blk_mq_tag_set *set,
set->map[HCTX_TYPE_POLL].nr_queues)
blk_queue_flag_set(QUEUE_FLAG_POLL, q);
- if (!(set->flags & BLK_MQ_F_SG_MERGE))
- blk_queue_flag_set(QUEUE_FLAG_NO_SG_MERGE, q);
-
q->sg_reserved_size = INT_MAX;
INIT_DELAYED_WORK(>requeue_work, blk_mq_requeue_work);
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 4b1be754cc41..ba9481f1bf3c 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -1698,14 +1698,6 @@ static int device_is_not_random(struct dm_target *ti,
struct dm_dev *dev,
return q && !blk_queue_add_random(q);
}
-static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
- sector_t start, sector_t
[Cluster-devel] [PATCH V14 18/18] block: kill BLK_MQ_F_SG_MERGE
QUEUE_FLAG_NO_SG_MERGE has been killed, so kill BLK_MQ_F_SG_MERGE too.
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
block/blk-mq-debugfs.c | 1 -
drivers/block/loop.c | 2 +-
drivers/block/nbd.c | 2 +-
drivers/block/rbd.c | 2 +-
drivers/block/skd_main.c | 1 -
drivers/block/xen-blkfront.c | 2 +-
drivers/md/dm-rq.c | 2 +-
drivers/mmc/core/queue.c | 3 +--
drivers/scsi/scsi_lib.c | 2 +-
include/linux/blk-mq.h | 1 -
10 files changed, 7 insertions(+), 11 deletions(-)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 2f9a11ef5bad..2ba0aa05ce13 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -250,7 +250,6 @@ static const char *const alloc_policy_name[] = {
static const char *const hctx_flag_name[] = {
HCTX_FLAG_NAME(SHOULD_MERGE),
HCTX_FLAG_NAME(TAG_SHARED),
- HCTX_FLAG_NAME(SG_MERGE),
HCTX_FLAG_NAME(BLOCKING),
HCTX_FLAG_NAME(NO_SCHED),
};
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 168a151aba49..714924cfb050 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -1937,7 +1937,7 @@ static int loop_add(struct loop_device **l, int i)
lo->tag_set.queue_depth = 128;
lo->tag_set.numa_node = NUMA_NO_NODE;
lo->tag_set.cmd_size = sizeof(struct loop_cmd);
- lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ lo->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
lo->tag_set.driver_data = lo;
err = blk_mq_alloc_tag_set(>tag_set);
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 08696f5f00bb..999c94de78e5 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -1570,7 +1570,7 @@ static int nbd_dev_add(int index)
nbd->tag_set.numa_node = NUMA_NO_NODE;
nbd->tag_set.cmd_size = sizeof(struct nbd_cmd);
nbd->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
- BLK_MQ_F_SG_MERGE | BLK_MQ_F_BLOCKING;
+ BLK_MQ_F_BLOCKING;
nbd->tag_set.driver_data = nbd;
err = blk_mq_alloc_tag_set(>tag_set);
diff --git a/drivers/block/rbd.c b/drivers/block/rbd.c
index 1e92b61d0bd5..abe9e1c89227 100644
--- a/drivers/block/rbd.c
+++ b/drivers/block/rbd.c
@@ -3988,7 +3988,7 @@ static int rbd_init_disk(struct rbd_device *rbd_dev)
rbd_dev->tag_set.ops = _mq_ops;
rbd_dev->tag_set.queue_depth = rbd_dev->opts->queue_depth;
rbd_dev->tag_set.numa_node = NUMA_NO_NODE;
- rbd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ rbd_dev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
rbd_dev->tag_set.nr_hw_queues = 1;
rbd_dev->tag_set.cmd_size = sizeof(struct work_struct);
diff --git a/drivers/block/skd_main.c b/drivers/block/skd_main.c
index ab893a7571a2..7d3ad6c22ee5 100644
--- a/drivers/block/skd_main.c
+++ b/drivers/block/skd_main.c
@@ -2843,7 +2843,6 @@ static int skd_cons_disk(struct skd_device *skdev)
skdev->sgs_per_request * sizeof(struct scatterlist);
skdev->tag_set.numa_node = NUMA_NO_NODE;
skdev->tag_set.flags = BLK_MQ_F_SHOULD_MERGE |
- BLK_MQ_F_SG_MERGE |
BLK_ALLOC_POLICY_TO_MQ_FLAG(BLK_TAG_ALLOC_FIFO);
skdev->tag_set.driver_data = skdev;
rc = blk_mq_alloc_tag_set(>tag_set);
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 0ed4b200fa58..d43a5677ccbc 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -977,7 +977,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
sector_size,
} else
info->tag_set.queue_depth = BLK_RING_SIZE(info);
info->tag_set.numa_node = NUMA_NO_NODE;
- info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE;
info->tag_set.cmd_size = sizeof(struct blkif_req);
info->tag_set.driver_data = info;
diff --git a/drivers/md/dm-rq.c b/drivers/md/dm-rq.c
index 4eb5f8c56535..b2f8eb2365ee 100644
--- a/drivers/md/dm-rq.c
+++ b/drivers/md/dm-rq.c
@@ -527,7 +527,7 @@ int dm_mq_init_request_queue(struct mapped_device *md,
struct dm_table *t)
md->tag_set->ops = _mq_ops;
md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
md->tag_set->numa_node = md->numa_node_id;
- md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
+ md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
md->tag_set->driver_data = md;
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 35cc138b096d..cc19e71c71d4 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -410,8 +410,7 @@ int mmc_init_queue(struct mmc_queue *mq, struct mmc_card
*card)
else
mq->tag_set.queue_depth = MMC_QUEUE_DEPTH;
mq->tag_set.numa_node = NUMA_NO_NODE;
-
[Cluster-devel] [PATCH V14 16/18] block: document usage of bio iterator helpers
Now multi-page bvec is supported, some helpers may return page by page, meantime some may return segment by segment, this patch documents the usage. Reviewed-by: Christoph Hellwig Reviewed-by: Omar Sandoval Signed-off-by: Ming Lei --- Documentation/block/biovecs.txt | 25 + 1 file changed, 25 insertions(+) diff --git a/Documentation/block/biovecs.txt b/Documentation/block/biovecs.txt index 25689584e6e0..4a466bcb9611 100644 --- a/Documentation/block/biovecs.txt +++ b/Documentation/block/biovecs.txt @@ -117,3 +117,28 @@ Other implications: size limitations and the limitations of the underlying devices. Thus there's no need to define ->merge_bvec_fn() callbacks for individual block drivers. + +Usage of helpers: += + +* The following helpers whose names have the suffix of "_all" can only be used +on non-BIO_CLONED bio. They are usually used by filesystem code. Drivers +shouldn't use them because the bio may have been split before it reached the +driver. + + bio_for_each_segment_all() + bio_first_bvec_all() + bio_first_page_all() + bio_last_bvec_all() + +* The following helpers iterate over single-page segment. The passed 'struct +bio_vec' will contain a single-page IO vector during the iteration + + bio_for_each_segment() + bio_for_each_segment_all() + +* The following helpers iterate over multi-page bvec. The passed 'struct +bio_vec' will contain a multi-page IO vector during the iteration + + bio_for_each_mp_bvec() + rq_for_each_mp_bvec() -- 2.9.5
[Cluster-devel] [PATCH V14 15/18] block: always define BIO_MAX_PAGES as 256
Now multi-page bvec can cover CONFIG_THP_SWAP, so we don't need to increase BIO_MAX_PAGES for it. CONFIG_THP_SWAP needs to split one THP into normal pages and adds them all to one bio. With multipage-bvec, it just takes one bvec to hold them all. Reviewed-by: Omar Sandoval Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei --- include/linux/bio.h | 8 1 file changed, 8 deletions(-) diff --git a/include/linux/bio.h b/include/linux/bio.h index af288f6e8ab0..1d279a6ae737 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -34,15 +34,7 @@ #define BIO_BUG_ON #endif -#ifdef CONFIG_THP_SWAP -#if HPAGE_PMD_NR > 256 -#define BIO_MAX_PAGES HPAGE_PMD_NR -#else #define BIO_MAX_PAGES 256 -#endif -#else -#define BIO_MAX_PAGES 256 -#endif #define bio_prio(bio) (bio)->bi_ioprio #define bio_set_prio(bio, prio)((bio)->bi_ioprio = prio) -- 2.9.5
[Cluster-devel] [PATCH V14 12/18] bcache: avoid to use bio_for_each_segment_all() in bch_bio_alloc_pages()
bch_bio_alloc_pages() is always called on one new bio, so it is safe
to access the bvec table directly. Given it is the only kind of this
case, open code the bvec table access since bio_for_each_segment_all()
will be changed to support for iterating over multipage bvec.
Acked-by: Coly Li
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Signed-off-by: Ming Lei
---
drivers/md/bcache/util.c | 6 +-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/md/bcache/util.c b/drivers/md/bcache/util.c
index 20eddeac1531..62fb917f7a4f 100644
--- a/drivers/md/bcache/util.c
+++ b/drivers/md/bcache/util.c
@@ -270,7 +270,11 @@ int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask)
int i;
struct bio_vec *bv;
- bio_for_each_segment_all(bv, bio, i) {
+ /*
+* This is called on freshly new bio, so it is safe to access the
+* bvec table directly.
+*/
+ for (i = 0, bv = bio->bi_io_vec; i < bio->bi_vcnt; bv++, i++) {
bv->bv_page = alloc_page(gfp_mask);
if (!bv->bv_page) {
while (--bv >= bio->bi_io_vec)
--
2.9.5
[Cluster-devel] [PATCH V14 11/18] block: loop: pass multi-page bvec to iov_iter
iov_iter is implemented on bvec itererator helpers, so it is safe to pass
multi-page bvec to it, and this way is much more efficient than passing one
page in each bvec.
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
drivers/block/loop.c | 20 ++--
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index cf5538942834..168a151aba49 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -511,21 +511,22 @@ static int lo_rw_aio(struct loop_device *lo, struct
loop_cmd *cmd,
loff_t pos, bool rw)
{
struct iov_iter iter;
+ struct req_iterator rq_iter;
struct bio_vec *bvec;
struct request *rq = blk_mq_rq_from_pdu(cmd);
struct bio *bio = rq->bio;
struct file *file = lo->lo_backing_file;
+ struct bio_vec tmp;
unsigned int offset;
- int segments = 0;
+ int nr_bvec = 0;
int ret;
+ rq_for_each_mp_bvec(tmp, rq, rq_iter)
+ nr_bvec++;
+
if (rq->bio != rq->biotail) {
- struct req_iterator iter;
- struct bio_vec tmp;
- __rq_for_each_bio(bio, rq)
- segments += bio_segments(bio);
- bvec = kmalloc_array(segments, sizeof(struct bio_vec),
+ bvec = kmalloc_array(nr_bvec, sizeof(struct bio_vec),
GFP_NOIO);
if (!bvec)
return -EIO;
@@ -534,10 +535,10 @@ static int lo_rw_aio(struct loop_device *lo, struct
loop_cmd *cmd,
/*
* The bios of the request may be started from the middle of
* the 'bvec' because of bio splitting, so we can't directly
-* copy bio->bi_iov_vec to new bvec. The rq_for_each_segment
+* copy bio->bi_iov_vec to new bvec. The rq_for_each_mp_bvec
* API will take care of all details for us.
*/
- rq_for_each_segment(tmp, rq, iter) {
+ rq_for_each_mp_bvec(tmp, rq, rq_iter) {
*bvec = tmp;
bvec++;
}
@@ -551,11 +552,10 @@ static int lo_rw_aio(struct loop_device *lo, struct
loop_cmd *cmd,
*/
offset = bio->bi_iter.bi_bvec_done;
bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
- segments = bio_segments(bio);
}
atomic_set(>ref, 2);
- iov_iter_bvec(, rw, bvec, segments, blk_rq_bytes(rq));
+ iov_iter_bvec(, rw, bvec, nr_bvec, blk_rq_bytes(rq));
iter.iov_offset = offset;
cmd->iocb.ki_pos = pos;
--
2.9.5
[Cluster-devel] [PATCH V14 09/18] fs/buffer.c: use bvec iterator to truncate the bio
Once multi-page bvec is enabled, the last bvec may include more than one
page, this patch use mp_bvec_last_segment() to truncate the bio.
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Signed-off-by: Ming Lei
---
fs/buffer.c | 5 -
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/buffer.c b/fs/buffer.c
index 52d024bfdbc1..817871274c77 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -3032,7 +3032,10 @@ void guard_bio_eod(int op, struct bio *bio)
/* ..and clear the end of the buffer for reads */
if (op == REQ_OP_READ) {
- zero_user(bvec->bv_page, bvec->bv_offset + bvec->bv_len,
+ struct bio_vec bv;
+
+ mp_bvec_last_segment(bvec, );
+ zero_user(bv.bv_page, bv.bv_offset + bv.bv_len,
truncated_bytes);
}
}
--
2.9.5
[Cluster-devel] [PATCH V14 14/18] block: enable multipage bvecs
This patch pulls the trigger for multi-page bvecs.
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
block/bio.c | 22 +++---
fs/iomap.c | 4 ++--
fs/xfs/xfs_aops.c | 4 ++--
include/linux/bio.h | 2 +-
4 files changed, 20 insertions(+), 12 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 968b12fea564..83a2dfa417ca 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -753,6 +753,8 @@ EXPORT_SYMBOL(bio_add_pc_page);
* @page: page to add
* @len: length of the data to add
* @off: offset of the data in @page
+ * @same_page: if %true only merge if the new data is in the same physical
+ * page as the last segment of the bio.
*
* Try to add the data at @page + @off to the last bvec of @bio. This is a
* a useful optimisation for file systems with a block size smaller than the
@@ -761,19 +763,25 @@ EXPORT_SYMBOL(bio_add_pc_page);
* Return %true on success or %false on failure.
*/
bool __bio_try_merge_page(struct bio *bio, struct page *page,
- unsigned int len, unsigned int off)
+ unsigned int len, unsigned int off, bool same_page)
{
if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))
return false;
if (bio->bi_vcnt > 0) {
struct bio_vec *bv = >bi_io_vec[bio->bi_vcnt - 1];
+ phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) +
+ bv->bv_offset + bv->bv_len - 1;
+ phys_addr_t page_addr = page_to_phys(page);
- if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) {
- bv->bv_len += len;
- bio->bi_iter.bi_size += len;
- return true;
- }
+ if (vec_end_addr + 1 != page_addr + off)
+ return false;
+ if (same_page && (vec_end_addr & PAGE_MASK) != page_addr)
+ return false;
+
+ bv->bv_len += len;
+ bio->bi_iter.bi_size += len;
+ return true;
}
return false;
}
@@ -819,7 +827,7 @@ EXPORT_SYMBOL_GPL(__bio_add_page);
int bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
- if (!__bio_try_merge_page(bio, page, len, offset)) {
+ if (!__bio_try_merge_page(bio, page, len, offset, false)) {
if (bio_full(bio))
return 0;
__bio_add_page(bio, page, len, offset);
diff --git a/fs/iomap.c b/fs/iomap.c
index af736acd9006..0c350e658b7f 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -318,7 +318,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos,
loff_t length, void *data,
*/
sector = iomap_sector(iomap, pos);
if (ctx->bio && bio_end_sector(ctx->bio) == sector) {
- if (__bio_try_merge_page(ctx->bio, page, plen, poff))
+ if (__bio_try_merge_page(ctx->bio, page, plen, poff, true))
goto done;
is_contig = true;
}
@@ -349,7 +349,7 @@ iomap_readpage_actor(struct inode *inode, loff_t pos,
loff_t length, void *data,
ctx->bio->bi_end_io = iomap_read_end_io;
}
- __bio_add_page(ctx->bio, page, plen, poff);
+ bio_add_page(ctx->bio, page, plen, poff);
done:
/*
* Move the caller beyond our range so that it keeps making progress.
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 1f1829e506e8..b9fd44168f61 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -616,12 +616,12 @@ xfs_add_to_ioend(
bdev, sector);
}
- if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff)) {
+ if (!__bio_try_merge_page(wpc->ioend->io_bio, page, len, poff, true)) {
if (iop)
atomic_inc(>write_count);
if (bio_full(wpc->ioend->io_bio))
xfs_chain_bio(wpc->ioend, wbc, bdev, sector);
- __bio_add_page(wpc->ioend->io_bio, page, len, poff);
+ bio_add_page(wpc->ioend->io_bio, page, len, poff);
}
wpc->ioend->io_size += len;
diff --git a/include/linux/bio.h b/include/linux/bio.h
index e6a6f3d78afd..af288f6e8ab0 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -441,7 +441,7 @@ extern int bio_add_page(struct bio *, struct page *,
unsigned int,unsigned int);
extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
unsigned int, unsigned int);
bool __bio_try_merge_page(struct bio *bio, struct page *page,
- unsigned int len, unsigned int off);
+ unsigned int len, unsigned int off, bool same_page);
void __bio_add_page(struct bio *bio, struct page *page,
unsigned int len, unsigned int off);
int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
--
2.9.5
[Cluster-devel] [PATCH V14 13/18] block: allow bio_for_each_segment_all() to iterate over multi-page bvec
This patch introduces one extra iterator variable to bio_for_each_segment_all(),
then we can allow bio_for_each_segment_all() to iterate over multi-page bvec.
Given it is just one mechannical & simple change on all
bio_for_each_segment_all()
users, this patch does tree-wide change in one single patch, so that we can
avoid to use a temporary helper for this conversion.
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Signed-off-by: Ming Lei
---
block/bio.c | 27 ++-
block/bounce.c| 6 --
drivers/md/bcache/btree.c | 3 ++-
drivers/md/dm-crypt.c | 3 ++-
drivers/md/raid1.c| 3 ++-
drivers/staging/erofs/data.c | 3 ++-
drivers/staging/erofs/unzip_vle.c | 3 ++-
fs/block_dev.c| 6 --
fs/btrfs/compression.c| 3 ++-
fs/btrfs/disk-io.c| 3 ++-
fs/btrfs/extent_io.c | 9 ++---
fs/btrfs/inode.c | 6 --
fs/btrfs/raid56.c | 3 ++-
fs/crypto/bio.c | 3 ++-
fs/direct-io.c| 4 +++-
fs/exofs/ore.c| 3 ++-
fs/exofs/ore_raid.c | 3 ++-
fs/ext4/page-io.c | 3 ++-
fs/ext4/readpage.c| 3 ++-
fs/f2fs/data.c| 9 ++---
fs/gfs2/lops.c| 9 ++---
fs/gfs2/meta_io.c | 3 ++-
fs/iomap.c| 6 --
fs/mpage.c| 3 ++-
fs/xfs/xfs_aops.c | 5 +++--
include/linux/bio.h | 11 +--
include/linux/bvec.h | 30 ++
27 files changed, 127 insertions(+), 46 deletions(-)
diff --git a/block/bio.c b/block/bio.c
index 4db1008309ed..968b12fea564 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1072,8 +1072,9 @@ static int bio_copy_from_iter(struct bio *bio, struct
iov_iter *iter)
{
int i;
struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i, iter_all) {
ssize_t ret;
ret = copy_page_from_iter(bvec->bv_page,
@@ -1103,8 +1104,9 @@ static int bio_copy_to_iter(struct bio *bio, struct
iov_iter iter)
{
int i;
struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i, iter_all) {
ssize_t ret;
ret = copy_page_to_iter(bvec->bv_page,
@@ -1126,8 +1128,9 @@ void bio_free_pages(struct bio *bio)
{
struct bio_vec *bvec;
int i;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec, bio, i)
+ bio_for_each_segment_all(bvec, bio, i, iter_all)
__free_page(bvec->bv_page);
}
EXPORT_SYMBOL(bio_free_pages);
@@ -1295,6 +1298,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
struct bio *bio;
int ret;
struct bio_vec *bvec;
+ struct bvec_iter_all iter_all;
if (!iov_iter_count(iter))
return ERR_PTR(-EINVAL);
@@ -1368,7 +1372,7 @@ struct bio *bio_map_user_iov(struct request_queue *q,
return bio;
out_unmap:
- bio_for_each_segment_all(bvec, bio, j) {
+ bio_for_each_segment_all(bvec, bio, j, iter_all) {
put_page(bvec->bv_page);
}
bio_put(bio);
@@ -1379,11 +1383,12 @@ static void __bio_unmap_user(struct bio *bio)
{
struct bio_vec *bvec;
int i;
+ struct bvec_iter_all iter_all;
/*
* make sure we dirty pages we wrote to
*/
- bio_for_each_segment_all(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i, iter_all) {
if (bio_data_dir(bio) == READ)
set_page_dirty_lock(bvec->bv_page);
@@ -1475,8 +1480,9 @@ static void bio_copy_kern_endio_read(struct bio *bio)
char *p = bio->bi_private;
struct bio_vec *bvec;
int i;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i, iter_all) {
memcpy(p, page_address(bvec->bv_page), bvec->bv_len);
p += bvec->bv_len;
}
@@ -1585,8 +1591,9 @@ void bio_set_pages_dirty(struct bio *bio)
{
struct bio_vec *bvec;
int i;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec, bio, i) {
+ bio_for_each_segment_all(bvec, bio, i, iter_all) {
if (!PageCompound(bvec->bv_page))
set_page_dirty_lock(bvec->bv_page);
}
@@ -1596,8 +1603,9 @@ static void bio_release_pages(struct bio *bio)
{
struct bio_vec *bvec;
int i;
+ struct bvec_iter_all iter_all;
- bio_for_each_segment_all(bvec,
[Cluster-devel] [PATCH V14 10/18] btrfs: use mp_bvec_last_segment to get bio's last page
Preparing for supporting multi-page bvec.
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
fs/btrfs/extent_io.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index dc8ba3ee515d..986ef49b0269 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2697,11 +2697,12 @@ static int __must_check submit_one_bio(struct bio *bio,
int mirror_num,
{
blk_status_t ret = 0;
struct bio_vec *bvec = bio_last_bvec_all(bio);
- struct page *page = bvec->bv_page;
+ struct bio_vec bv;
struct extent_io_tree *tree = bio->bi_private;
u64 start;
- start = page_offset(page) + bvec->bv_offset;
+ mp_bvec_last_segment(bvec, );
+ start = page_offset(bv.bv_page) + bv.bv_offset;
bio->bi_private = NULL;
--
2.9.5
[Cluster-devel] [PATCH V14 07/18] block: use bio_for_each_mp_bvec() to map sg
It is more efficient to use bio_for_each_mp_bvec() to map sg, meantime
we have to consider splitting multipage bvec as done in blk_bio_segment_split().
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Signed-off-by: Ming Lei
---
block/blk-merge.c | 70 +++
1 file changed, 50 insertions(+), 20 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 2dfc30d8bc77..8a498f29636f 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -464,6 +464,54 @@ static int blk_phys_contig_segment(struct request_queue
*q, struct bio *bio,
return biovec_phys_mergeable(q, _bv, _bv);
}
+static struct scatterlist *blk_next_sg(struct scatterlist **sg,
+ struct scatterlist *sglist)
+{
+ if (!*sg)
+ return sglist;
+
+ /*
+* If the driver previously mapped a shorter list, we could see a
+* termination bit prematurely unless it fully inits the sg table
+* on each mapping. We KNOW that there must be more entries here
+* or the driver would be buggy, so force clear the termination bit
+* to avoid doing a full sg_init_table() in drivers for each command.
+*/
+ sg_unmark_end(*sg);
+ return sg_next(*sg);
+}
+
+static unsigned blk_bvec_map_sg(struct request_queue *q,
+ struct bio_vec *bvec, struct scatterlist *sglist,
+ struct scatterlist **sg)
+{
+ unsigned nbytes = bvec->bv_len;
+ unsigned nsegs = 0, total = 0, offset = 0;
+
+ while (nbytes > 0) {
+ unsigned seg_size;
+ struct page *pg;
+ unsigned idx;
+
+ *sg = blk_next_sg(sg, sglist);
+
+ seg_size = get_max_segment_size(q, bvec->bv_offset + total);
+ seg_size = min(nbytes, seg_size);
+
+ offset = (total + bvec->bv_offset) % PAGE_SIZE;
+ idx = (total + bvec->bv_offset) / PAGE_SIZE;
+ pg = nth_page(bvec->bv_page, idx);
+
+ sg_set_page(*sg, pg, seg_size, offset);
+
+ total += seg_size;
+ nbytes -= seg_size;
+ nsegs++;
+ }
+
+ return nsegs;
+}
+
static inline void
__blk_segment_map_sg(struct request_queue *q, struct bio_vec *bvec,
struct scatterlist *sglist, struct bio_vec *bvprv,
@@ -481,25 +529,7 @@ __blk_segment_map_sg(struct request_queue *q, struct
bio_vec *bvec,
(*sg)->length += nbytes;
} else {
new_segment:
- if (!*sg)
- *sg = sglist;
- else {
- /*
-* If the driver previously mapped a shorter
-* list, we could see a termination bit
-* prematurely unless it fully inits the sg
-* table on each mapping. We KNOW that there
-* must be more entries here or the driver
-* would be buggy, so force clear the
-* termination bit to avoid doing a full
-* sg_init_table() in drivers for each command.
-*/
- sg_unmark_end(*sg);
- *sg = sg_next(*sg);
- }
-
- sg_set_page(*sg, bvec->bv_page, nbytes, bvec->bv_offset);
- (*nsegs)++;
+ (*nsegs) += blk_bvec_map_sg(q, bvec, sglist, sg);
}
*bvprv = *bvec;
}
@@ -521,7 +551,7 @@ static int __blk_bios_map_sg(struct request_queue *q,
struct bio *bio,
int nsegs = 0;
for_each_bio(bio)
- bio_for_each_segment(bvec, bio, iter)
+ bio_for_each_mp_bvec(bvec, bio, iter)
__blk_segment_map_sg(q, , sglist, , sg,
);
--
2.9.5
[Cluster-devel] [PATCH V14 06/18] block: use bio_for_each_mp_bvec() to compute multi-page bvec count
First it is more efficient to use bio_for_each_mp_bvec() in both
blk_bio_segment_split() and __blk_recalc_rq_segments() to compute how
many multi-page bvecs there are in the bio.
Secondly once bio_for_each_mp_bvec() is used, the bvec may need to be
splitted because its length can be very longer than max segment size,
so we have to split the big bvec into several segments.
Thirdly when splitting multi-page bvec into segments, the max segment
limit may be reached, so the bio split need to be considered under
this situation too.
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
block/blk-merge.c | 103 +++---
1 file changed, 83 insertions(+), 20 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index f85d878f313d..2dfc30d8bc77 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -161,6 +161,73 @@ static inline unsigned get_max_io_size(struct
request_queue *q,
return sectors;
}
+static unsigned get_max_segment_size(struct request_queue *q,
+unsigned offset)
+{
+ unsigned long mask = queue_segment_boundary(q);
+
+ /* default segment boundary mask means no boundary limit */
+ if (mask == BLK_SEG_BOUNDARY_MASK)
+ return queue_max_segment_size(q);
+
+ return min_t(unsigned long, mask - (mask & offset) + 1,
+queue_max_segment_size(q));
+}
+
+/*
+ * Split the bvec @bv into segments, and update all kinds of
+ * variables.
+ */
+static bool bvec_split_segs(struct request_queue *q, struct bio_vec *bv,
+ unsigned *nsegs, unsigned *last_seg_size,
+ unsigned *front_seg_size, unsigned *sectors)
+{
+ unsigned len = bv->bv_len;
+ unsigned total_len = 0;
+ unsigned new_nsegs = 0, seg_size = 0;
+
+ /*
+* Multi-page bvec may be too big to hold in one segment, so the
+* current bvec has to be splitted as multiple segments.
+*/
+ while (len && new_nsegs + *nsegs < queue_max_segments(q)) {
+ seg_size = get_max_segment_size(q, bv->bv_offset + total_len);
+ seg_size = min(seg_size, len);
+
+ new_nsegs++;
+ total_len += seg_size;
+ len -= seg_size;
+
+ if ((bv->bv_offset + total_len) & queue_virt_boundary(q))
+ break;
+ }
+
+ if (!new_nsegs)
+ return !!len;
+
+ /* update front segment size */
+ if (!*nsegs) {
+ unsigned first_seg_size;
+
+ if (new_nsegs == 1)
+ first_seg_size = get_max_segment_size(q, bv->bv_offset);
+ else
+ first_seg_size = queue_max_segment_size(q);
+
+ if (*front_seg_size < first_seg_size)
+ *front_seg_size = first_seg_size;
+ }
+
+ /* update other varibles */
+ *last_seg_size = seg_size;
+ *nsegs += new_nsegs;
+ if (sectors)
+ *sectors += total_len >> 9;
+
+ /* split in the middle of the bvec if len != 0 */
+ return !!len;
+}
+
static struct bio *blk_bio_segment_split(struct request_queue *q,
struct bio *bio,
struct bio_set *bs,
@@ -174,7 +241,7 @@ static struct bio *blk_bio_segment_split(struct
request_queue *q,
struct bio *new = NULL;
const unsigned max_sectors = get_max_io_size(q, bio);
- bio_for_each_segment(bv, bio, iter) {
+ bio_for_each_mp_bvec(bv, bio, iter) {
/*
* If the queue doesn't support SG gaps and adding this
* offset would create a gap, disallow it.
@@ -189,8 +256,12 @@ static struct bio *blk_bio_segment_split(struct
request_queue *q,
*/
if (nsegs < queue_max_segments(q) &&
sectors < max_sectors) {
- nsegs++;
- sectors = max_sectors;
+ /* split in the middle of bvec */
+ bv.bv_len = (max_sectors - sectors) << 9;
+ bvec_split_segs(q, , ,
+ _size,
+ _seg_size,
+ );
}
goto split;
}
@@ -212,14 +283,12 @@ static struct bio *blk_bio_segment_split(struct
request_queue *q,
if (nsegs == queue_max_segments(q))
goto split;
- if (nsegs == 1 && seg_size > front_seg_size)
- front_seg_size = seg_size;
-
- nsegs++;
bvprv = bv;
bvprvp =
- seg_size = bv.bv_len;
-
[Cluster-devel] [PATCH V14 08/18] block: introduce mp_bvec_last_segment()
BTRFS and guard_bio_eod() need to get the last singlepage segment
from one multipage bvec, so introduce this helper to make them happy.
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
include/linux/bvec.h | 22 ++
1 file changed, 22 insertions(+)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 0ae729b1c9fe..21f76bad7be2 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -131,4 +131,26 @@ static inline bool bvec_iter_advance(const struct bio_vec
*bv,
.bi_bvec_done = 0,\
}
+/*
+ * Get the last single-page segment from the multi-page bvec and store it
+ * in @seg
+ */
+static inline void mp_bvec_last_segment(const struct bio_vec *bvec,
+ struct bio_vec *seg)
+{
+ unsigned total = bvec->bv_offset + bvec->bv_len;
+ unsigned last_page = (total - 1) / PAGE_SIZE;
+
+ seg->bv_page = nth_page(bvec->bv_page, last_page);
+
+ /* the whole segment is inside the last page */
+ if (bvec->bv_offset >= last_page * PAGE_SIZE) {
+ seg->bv_offset = bvec->bv_offset % PAGE_SIZE;
+ seg->bv_len = bvec->bv_len;
+ } else {
+ seg->bv_offset = 0;
+ seg->bv_len = total - last_page * PAGE_SIZE;
+ }
+}
+
#endif /* __LINUX_BVEC_ITER_H */
--
2.9.5
[Cluster-devel] [PATCH V14 04/18] block: introduce multi-page bvec helpers
This patch introduces helpers of 'mp_bvec_iter_*' for multi-page bvec
support.
The introduced helpers treate one bvec as real multi-page segment,
which may include more than one pages.
The existed helpers of bvec_iter_* are interfaces for supporting current
bvec iterator which is thought as single-page by drivers, fs, dm and
etc. These introduced helpers will build single-page bvec in flight, so
this way won't break current bio/bvec users, which needn't any change.
Follows some multi-page bvec background:
- bvecs stored in bio->bi_io_vec is always multi-page style
- bvec(struct bio_vec) represents one physically contiguous I/O
buffer, now the buffer may include more than one page after
multi-page bvec is supported, and all these pages represented
by one bvec is physically contiguous. Before multi-page bvec
support, at most one page is included in one bvec, we call it
single-page bvec.
- .bv_page of the bvec points to the 1st page in the multi-page bvec
- .bv_offset of the bvec is the offset of the buffer in the bvec
The effect on the current drivers/filesystem/dm/bcache/...:
- almost everyone supposes that one bvec only includes one single
page, so we keep the sp interface not changed, for example,
bio_for_each_segment() still returns single-page bvec
- bio_for_each_segment_all() will return single-page bvec too
- during iterating, iterator variable(struct bvec_iter) is always
updated in multi-page bvec style, and bvec_iter_advance() is kept
not changed
- returned(copied) single-page bvec is built in flight by bvec
helpers from the stored multi-page bvec
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
include/linux/bvec.h | 30 +++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index ba0ae40e77c9..0ae729b1c9fe 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -23,6 +23,7 @@
#include
#include
#include
+#include
/*
* was unsigned short, but we might as well be ready for > 64kB I/O pages
@@ -50,16 +51,39 @@ struct bvec_iter {
*/
#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
-#define bvec_iter_page(bvec, iter) \
+/* multi-page (mp_bvec) helpers */
+#define mp_bvec_iter_page(bvec, iter) \
(__bvec_iter_bvec((bvec), (iter))->bv_page)
-#define bvec_iter_len(bvec, iter) \
+#define mp_bvec_iter_len(bvec, iter) \
min((iter).bi_size, \
__bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
-#define bvec_iter_offset(bvec, iter) \
+#define mp_bvec_iter_offset(bvec, iter)\
(__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
+#define mp_bvec_iter_page_idx(bvec, iter) \
+ (mp_bvec_iter_offset((bvec), (iter)) / PAGE_SIZE)
+
+#define mp_bvec_iter_bvec(bvec, iter) \
+((struct bio_vec) {\
+ .bv_page= mp_bvec_iter_page((bvec), (iter)),\
+ .bv_len = mp_bvec_iter_len((bvec), (iter)), \
+ .bv_offset = mp_bvec_iter_offset((bvec), (iter)), \
+})
+
+/* For building single-page bvec in flight */
+ #define bvec_iter_offset(bvec, iter) \
+ (mp_bvec_iter_offset((bvec), (iter)) % PAGE_SIZE)
+
+#define bvec_iter_len(bvec, iter) \
+ min_t(unsigned, mp_bvec_iter_len((bvec), (iter)), \
+ PAGE_SIZE - bvec_iter_offset((bvec), (iter)))
+
+#define bvec_iter_page(bvec, iter) \
+ nth_page(mp_bvec_iter_page((bvec), (iter)), \
+mp_bvec_iter_page_idx((bvec), (iter)))
+
#define bvec_iter_bvec(bvec, iter) \
((struct bio_vec) {\
.bv_page= bvec_iter_page((bvec), (iter)), \
--
2.9.5
[Cluster-devel] [PATCH V14 03/18] block: remove bvec_iter_rewind()
Commit 7759eb23fd980 ("block: remove bio_rewind_iter()") removes
bio_rewind_iter(), then no one uses bvec_iter_rewind() any more,
so remove it.
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Signed-off-by: Ming Lei
---
include/linux/bvec.h | 24
1 file changed, 24 deletions(-)
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 02c73c6aa805..ba0ae40e77c9 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -92,30 +92,6 @@ static inline bool bvec_iter_advance(const struct bio_vec
*bv,
return true;
}
-static inline bool bvec_iter_rewind(const struct bio_vec *bv,
-struct bvec_iter *iter,
-unsigned int bytes)
-{
- while (bytes) {
- unsigned len = min(bytes, iter->bi_bvec_done);
-
- if (iter->bi_bvec_done == 0) {
- if (WARN_ONCE(iter->bi_idx == 0,
- "Attempted to rewind iter beyond "
- "bvec's boundaries\n")) {
- return false;
- }
- iter->bi_idx--;
- iter->bi_bvec_done = __bvec_iter_bvec(bv,
*iter)->bv_len;
- continue;
- }
- bytes -= len;
- iter->bi_size += len;
- iter->bi_bvec_done -= len;
- }
- return true;
-}
-
#define for_each_bvec(bvl, bio_vec, iter, start) \
for (iter = (start);\
(iter).bi_size && \
--
2.9.5
[Cluster-devel] [PATCH V14 05/18] block: introduce bio_for_each_mp_bvec() and rq_for_each_mp_bvec()
bio_for_each_mp_bvec() is used for iterating over multi-page bvec for bio
split & merge code.
rq_for_each_mp_bvec() can be used for drivers which may handle the
multi-page bvec directly, so far loop is one perfect use case.
Reviewed-by: Christoph Hellwig
Reviewed-by: Omar Sandoval
Signed-off-by: Ming Lei
---
include/linux/bio.h| 10 ++
include/linux/blkdev.h | 4
2 files changed, 14 insertions(+)
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 72b4f7be2106..730288145568 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -156,6 +156,16 @@ static inline void bio_advance_iter(struct bio *bio,
struct bvec_iter *iter,
#define bio_for_each_segment(bvl, bio, iter) \
__bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
+#define __bio_for_each_mp_bvec(bvl, bio, iter, start) \
+ for (iter = (start);\
+(iter).bi_size && \
+ ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
+bio_advance_iter((bio), &(iter), (bvl).bv_len))
+
+/* iterate over multi-page bvec */
+#define bio_for_each_mp_bvec(bvl, bio, iter) \
+ __bio_for_each_mp_bvec(bvl, bio, iter, (bio)->bi_iter)
+
#define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
static inline unsigned bio_segments(struct bio *bio)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 338604dff7d0..6ebae3ee8f44 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -797,6 +797,10 @@ struct req_iterator {
__rq_for_each_bio(_iter.bio, _rq) \
bio_for_each_segment(bvl, _iter.bio, _iter.iter)
+#define rq_for_each_mp_bvec(bvl, _rq, _iter) \
+ __rq_for_each_bio(_iter.bio, _rq) \
+ bio_for_each_mp_bvec(bvl, _iter.bio, _iter.iter)
+
#define rq_iter_last(bvec, _iter) \
(_iter.bio->bi_next == NULL && \
bio_iter_last(bvec, _iter.iter))
--
2.9.5
[Cluster-devel] [PATCH V14 02/18] block: don't use bio->bi_vcnt to figure out segment number
It is wrong to use bio->bi_vcnt to figure out how many segments
there are in the bio even though CLONED flag isn't set on this bio,
because this bio may be splitted or advanced.
So always use bio_segments() in blk_recount_segments(), and it shouldn't
cause any performance loss now because the physical segment number is figured
out in blk_queue_split() and BIO_SEG_VALID is set meantime since
bdced438acd83ad83a6c ("block: setup bi_phys_segments after splitting").
Reviewed-by: Omar Sandoval
Reviewed-by: Christoph Hellwig
Fixes: 76d8137a3113 ("blk-merge: recaculate segment if it isn't less than max
segments")
Signed-off-by: Ming Lei
---
block/blk-merge.c | 8 +---
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 71e9ac03f621..f85d878f313d 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -367,13 +367,7 @@ void blk_recalc_rq_segments(struct request *rq)
void blk_recount_segments(struct request_queue *q, struct bio *bio)
{
- unsigned short seg_cnt;
-
- /* estimate segment number by bi_vcnt for non-cloned bio */
- if (bio_flagged(bio, BIO_CLONED))
- seg_cnt = bio_segments(bio);
- else
- seg_cnt = bio->bi_vcnt;
+ unsigned short seg_cnt = bio_segments(bio);
if (test_bit(QUEUE_FLAG_NO_SG_MERGE, >queue_flags) &&
(seg_cnt < queue_max_segments(q)))
--
2.9.5
[Cluster-devel] [PATCH V14 00/18] block: support multi-page bvec
Hi, This patchset brings multi-page bvec into block layer: 1) what is multi-page bvec? Multipage bvecs means that one 'struct bio_bvec' can hold multiple pages which are physically contiguous instead of one single page used in linux kernel for long time. 2) why is multi-page bvec introduced? Kent proposed the idea[1] first. As system's RAM becomes much bigger than before, and huge page, transparent huge page and memory compaction are widely used, it is a bit easy now to see physically contiguous pages from fs in I/O. On the other hand, from block layer's view, it isn't necessary to store intermediate pages into bvec, and it is enough to just store the physicallly contiguous 'segment' in each io vector. Also huge pages are being brought to filesystem and swap [2][6], we can do IO on a hugepage each time[3], which requires that one bio can transfer at least one huge page one time. Turns out it isn't flexiable to change BIO_MAX_PAGES simply[3][5]. Multipage bvec can fit in this case very well. As we saw, if CONFIG_THP_SWAP is enabled, BIO_MAX_PAGES can be configured as much bigger, such as 512, which requires at least two 4K pages for holding the bvec table. With multi-page bvec: - Inside block layer, both bio splitting and sg map can become more efficient than before by just traversing the physically contiguous 'segment' instead of each page. - segment handling in block layer can be improved much in future since it should be quite easy to convert multipage bvec into segment easily. For example, we might just store segment in each bvec directly in future. - bio size can be increased and it should improve some high-bandwidth IO case in theory[4]. - there is opportunity in future to improve memory footprint of bvecs. 3) how is multi-page bvec implemented in this patchset? Patch 1 ~ 3 parpares for supporting multi-page bvec. Patches 4 ~ 14 implement multipage bvec in block layer: - put all tricks into bvec/bio/rq iterators, and as far as drivers and fs use these standard iterators, they are happy with multipage bvec - introduce bio_for_each_bvec() to iterate over multipage bvec for splitting bio and mapping sg - keep current bio_for_each_segment*() to itereate over singlepage bvec and make sure current users won't be broken; especailly, convert to this new helper prototype in single patch 21 given it is bascially a mechanism conversion - deal with iomap & xfs's sub-pagesize io vec in patch 13 - enalbe multipage bvec in patch 14 Patch 15 redefines BIO_MAX_PAGES as 256. Patch 16 documents usages of bio iterator helpers. Patch 17~18 kills NO_SG_MERGE. These patches can be found in the following git tree: git: https://github.com/ming1/linux.git v5.0-blk_mp_bvec_v14 Lots of test(blktest, xfstests, ltp io, ...) have been run with this patchset, and not see regression. Thanks Christoph for reviewing the early version and providing very good suggestions, such as: introduce bio_init_with_vec_table(), remove another unnecessary helpers for cleanup and so on. Thanks Chritoph and Omar for reviewing V10/V11/V12, and provides lots of helpful comments. V14: - drop patch(patch 4 in V13) for renaming bvec helpers, as suggested by Jens - use mp_bvec_* as multi-page bvec helper name - fix one build issue, which is caused by missing one converion of bio_for_each_segment_all in fs/gfs2 - fix one 32bit ARCH specific issue caused by segment boundary mask overflow V13: - rebase on v5.0-rc2 - address Omar's comment on patch 1 of V12 by using V11's approach - rename one local vairable in patch 15 as suggested by Christoph V12: - deal with non-cluster by max segment size & segment boundary limit - rename bvec helper's name - revert new change on bvec_iter_advance() in V11 - introduce rq_for_each_bvec() - use simpler check on enalbing multi-page bvec - fix Document change V11: - address most of reviews from Omar and christoph - rename mp_bvec_* as segment_* helpers - remove 'mp' parameter from bvec_iter_advance() and related helpers - cleanup patch on bvec_split_segs() and blk_bio_segment_split(), remove unnecessary checks - simplify bvec_last_segment() - drop bio_pages_all() - introduce dedicated functions/file for handling non-cluser bio for avoiding checking queue cluster before adding page to bio - introduce bio_try_merge_segment() for simplifying iomap/xfs page accounting code - Fix Document change V10: - no any code change, just add more guys and list into patch's CC list, as suggested by Christoph and Dave Chinner V9: - fix regression on iomap's sub-pagesize io vec, covered by patch 13 V8: - remove prepare patches which all are merged to linus tree
[Cluster-devel] [PATCH V14 01/18] btrfs: look at bi_size for repair decisions
From: Christoph Hellwig
bio_readpage_error currently uses bi_vcnt to decide if it is worth
retrying an I/O. But the vector count is mostly an implementation
artifact - it really should figure out if there is more than a
single sector worth retrying. Use bi_size for that and shift by
PAGE_SHIFT. This really should be blocks/sectors, but given that
btrfs doesn't support a sector size different from the PAGE_SIZE
using the page size keeps the changes to a minimum.
Reviewed-by: Omar Sandoval
Reviewed-by: David Sterba
Signed-off-by: Christoph Hellwig
---
fs/btrfs/extent_io.c | 2 +-
include/linux/bio.h | 6 --
2 files changed, 1 insertion(+), 7 deletions(-)
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 52abe4082680..dc8ba3ee515d 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2350,7 +2350,7 @@ static int bio_readpage_error(struct bio *failed_bio, u64
phy_offset,
int read_mode = 0;
blk_status_t status;
int ret;
- unsigned failed_bio_pages = bio_pages_all(failed_bio);
+ unsigned failed_bio_pages = failed_bio->bi_iter.bi_size >> PAGE_SHIFT;
BUG_ON(bio_op(failed_bio) == REQ_OP_WRITE);
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 7380b094dcca..72b4f7be2106 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -263,12 +263,6 @@ static inline void bio_get_last_bvec(struct bio *bio,
struct bio_vec *bv)
bv->bv_len = iter.bi_bvec_done;
}
-static inline unsigned bio_pages_all(struct bio *bio)
-{
- WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
- return bio->bi_vcnt;
-}
-
static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
{
WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
--
2.9.5
