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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-04 22:16:35 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-02-04 22:16:35 +0300 |
| commit | 64b28683deba132f301d1cecfc25c32e295f53a1 (patch) | |
| tree | be38a4e77c530fb129339f983a9d307c60312df8 /include/linux/buffer_head.h | |
| parent | d3658c2266012f270da52e3e0365536e394bd3bd (diff) | |
| parent | 1d51877578799bfe0fcfe189d8233c9fccf05931 (diff) | |
| download | linux-64b28683deba132f301d1cecfc25c32e295f53a1.tar.xz | |
Merge tag 'for-linus-20180204' of git://git.kernel.dk/linux-block
Pull more block updates from Jens Axboe:
"Most of this is fixes and not new code/features:
- skd fix from Arnd, fixing a build error dependent on sla allocator
type.
- blk-mq scheduler discard merging fixes, one from me and one from
Keith. This fixes a segment miscalculation for blk-mq-sched, where
we mistakenly think two segments are physically contigious even
though the request isn't carrying real data. Also fixes a bio-to-rq
merge case.
- Don't re-set a bit on the buffer_head flags, if it's already set.
This can cause scalability concerns on bigger machines and
workloads. From Kemi Wang.
- Add BLK_STS_DEV_RESOURCE return value to blk-mq, allowing us to
distuingish between a local (device related) resource starvation
and a global one. The latter might happen without IO being in
flight, so it has to be handled a bit differently. From Ming"
* tag 'for-linus-20180204' of git://git.kernel.dk/linux-block:
block: skd: fix incorrect linux/slab_def.h inclusion
buffer: Avoid setting buffer bits that are already set
blk-mq-sched: Enable merging discard bio into request
blk-mq: fix discard merge with scheduler attached
blk-mq: introduce BLK_STS_DEV_RESOURCE
Diffstat (limited to 'include/linux/buffer_head.h')
| -rw-r--r-- | include/linux/buffer_head.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h index 58a82f58e44e..894e5d125de6 100644 --- a/include/linux/buffer_head.h +++ b/include/linux/buffer_head.h @@ -81,11 +81,14 @@ struct buffer_head { /* * macro tricks to expand the set_buffer_foo(), clear_buffer_foo() * and buffer_foo() functions. + * To avoid reset buffer flags that are already set, because that causes + * a costly cache line transition, check the flag first. */ #define BUFFER_FNS(bit, name) \ static __always_inline void set_buffer_##name(struct buffer_head *bh) \ { \ - set_bit(BH_##bit, &(bh)->b_state); \ + if (!test_bit(BH_##bit, &(bh)->b_state)) \ + set_bit(BH_##bit, &(bh)->b_state); \ } \ static __always_inline void clear_buffer_##name(struct buffer_head *bh) \ { \ |