linux-toradex.git/block/blk-merge.c, branch v4.4.1

Revert "block: Split bios on chunk boundaries"

2016-01-08T16:00:29+00:00

This reverts commit d3805611130af9b911e908af9f67a3f64f4f0914.

If we end up splitting on the first segment, we don't adjust
the sector count. That results in hitting a BUG() with attempting
to split 0 sectors.

As this is just a performance issue and not a regression since
4.3 release, let's just rever this change. That gives us more
time to test a real fix for 4.5, which would be marked for
stable anyway.

block: Split bios on chunk boundaries

2015-12-23T00:19:25+00:00

For h/w that advertise their block storage's underlying chunk size, it's
a big performance win to not submit commands that cross them. This patch
uses that criteria if it is provided. If it is not provided, this patch
uses the max sectors as before.

Signed-off-by: Keith Busch 
Signed-off-by: Jens Axboe

blk-merge: fix computing bio->bi_seg_front_size in case of single segment

2015-11-30T20:02:36+00:00

When bio has only one physical segment, we should set bio's
bi_seg_front_size as the real(final) size of the single segment.

Fixes: 02e707424c2ea(blk-merge: fix blk_bio_segment_split)
Reported-by: Markus Trippelsdorf 
Tested-by: Markus Trippelsdorf 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-merge: warn if figured out segment number is bigger than nr_phys_segments

2015-11-24T03:16:55+00:00

We had seen lots of reports of this kind issue, so add one
warnning in blk-merge, then it can be triggered easily and
avoid to depend on warning/bug from drivers.

Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-merge: fix blk_bio_segment_split

2015-11-24T03:16:53+00:00

Commit bdced438acd83a(block: setup bi_phys_segments after
splitting) introduces function of computing bio->bi_phys_segments
during bio splitting.

Unfortunately both bio->bi_seg_front_size and bio->bi_seg_back_size
arn't computed, so too many physical segments may be obtained
for one request since both the two are used to check if one segment
across two bios can be possible.

This patch fixes the issue by computing the two variables in
blk_bio_segment_split().

Fixes: bdced438acd83a(block: setup bi_phys_segments after splitting)
Reported-by: Michael Ellerman 
Reported-by: Mark Salter 
Tested-by: Laurent Dufour 
Tested-by: Mark Salter 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: fix segment split

2015-11-24T03:16:51+00:00

Inside blk_bio_segment_split(), previous bvec pointer(bvprvp)
always points to the iterator local variable, which is obviously
wrong, so fix it by pointing to the local variable of 'bvprv'.

Fixes: 5014c311baa2b(block: fix bogus compiler warnings in blk-merge.c)
Cc: stable@kernel.org #4.3
Reported-by: Michael Ellerman 
Reported-by: Mark Salter 
Tested-by: Laurent Dufour 
Tested-by: Mark Salter 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: avoid to merge splitted bio

2015-10-21T21:00:51+00:00

The splitted bio has been already too fat to merge, so mark it
as NOMERGE.

Reviewed-by: Jeff Moyer 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: setup bi_phys_segments after splitting

2015-10-21T21:00:50+00:00

The number of bio->bi_phys_segments is always obtained
during bio splitting, so it is natural to setup it
just after bio splitting, then we can avoid to compute
nr_segment again during merge.

Reviewed-by: Jeff Moyer 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: blk-merge: fast-clone bio when splitting rw bios

2015-09-17T15:58:38+00:00

biovecs has become immutable since v3.13, so it isn't necessary
to allocate biovecs for the new cloned bios, then we can save
one extra biovecs allocation/copy, and the allocation is often
not fixed-length and a bit more expensive.

For example, if the 'max_sectors_kb' of null blk's queue is set
as 16(32 sectors) via sysfs just for making more splits, this patch
can increase throught about ~70% in the sequential read test over
null_blk(direct io, bs: 1M).

Cc: Christoph Hellwig 
Cc: Kent Overstreet 
Cc: Ming Lin 
Cc: Dongsu Park 
Signed-off-by: Ming Lei 

This fixes a performance regression introduced by commit 54efd50bfd,
and allows us to take full advantage of the fact that we have immutable
bio_vecs. Hand applied, as it rejected violently with commit
5014c311baa2.

Signed-off-by: Jens Axboe

block: Refuse request/bio merges with gaps in the integrity payload

2015-09-11T15:03:04+00:00

If a driver sets the block queue virtual boundary mask, it means that
it cannot handle gaps so we must not allow those in the integrity
payload as well.

Signed-off-by: Sagi Grimberg 

Fixed up by me to have duplicate integrity merge functions, depending
on whether block integrity is enabled or not. Fixes a compilations
issue with CONFIG_BLK_DEV_INTEGRITY unset.

Signed-off-by: Jens Axboe