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:
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
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
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
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
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
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(-)
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
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
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
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
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
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
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
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
---
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
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
> >
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?
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
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
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
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
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
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