linux/block
Ming Lei 52cc6eead9 block: blk-merge: fast-clone bio when splitting rw bios
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 <hch@infradead.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Ming Lin <ming.l@ssi.samsung.com>
Cc: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lei <ming.lei@canonical.com>

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
5014c311ba.

Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-17 09:58:38 -06:00
..
partitions Merge branch 'for-3.20/core' of git://git.kernel.dk/linux-block 2015-02-12 14:13:23 -08:00
bio-integrity.c block: Refuse adding appending a gapped integrity page to a bio 2015-09-11 09:03:45 -06:00
bio.c Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block 2015-09-02 13:10:25 -07:00
blk-cgroup.c block: blkg_destroy_all() should clear q->root_blkg and ->root_rl.blkg 2015-09-11 09:03:50 -06:00
blk-core.c block: make generic_make_request handle arbitrarily sized bios 2015-08-13 12:31:33 -06:00
blk-exec.c block: move PM request support to IDE 2015-05-05 13:40:42 -06:00
blk-flush.c blk-mq: fix race between timeout and freeing request 2015-08-15 09:45:21 -06:00
blk-integrity.c block: Refuse request/bio merges with gaps in the integrity payload 2015-09-11 09:03:04 -06:00
blk-ioc.c block: Substitute rcu_access_pointer() for rcu_dereference_raw() 2014-02-18 12:21:26 -08:00
blk-iopoll.c Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-03 12:57:53 -07:00
blk-lib.c block: remove split code in blkdev_issue_{discard,write_same} 2015-08-13 12:31:47 -06:00
blk-map.c block: Copy a user iovec if it includes gaps 2015-09-11 09:03:50 -06:00
blk-merge.c block: blk-merge: fast-clone bio when splitting rw bios 2015-09-17 09:58:38 -06:00
blk-mq-cpu.c blk-mq: add file comments and update copyright notices 2014-05-28 10:15:41 -06:00
blk-mq-cpumap.c sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask() 2015-05-27 15:22:15 +02:00
blk-mq-sysfs.c blk-mq: fix buffer overflow when reading sysfs file of 'pending' 2015-08-15 09:45:19 -06:00
blk-mq-tag.c blk-mq: fix race between timeout and freeing request 2015-08-15 09:45:21 -06:00
blk-mq-tag.h blk-mq: fix race between timeout and freeing request 2015-08-15 09:45:21 -06:00
blk-mq.c blk-mq: fix race between timeout and freeing request 2015-08-15 09:45:21 -06:00
blk-mq.h blk-mq: release mq's kobjects in blk_release_queue() 2015-01-29 08:30:51 -08:00
blk-settings.c Merge branch 'for-4.3/core' of git://git.kernel.dk/linux-block 2015-09-02 13:10:25 -07:00
blk-softirq.c block: fix regression with block enabled tagging 2014-04-09 21:54:06 -06:00
blk-sysfs.c block: make generic_make_request handle arbitrarily sized bios 2015-08-13 12:31:33 -06:00
blk-tag.c block: support different tag allocation policy 2015-01-23 14:15:46 -07:00
blk-throttle.c blkcg: move block/blk-cgroup.h to include/linux/blk-cgroup.h 2015-06-02 08:33:33 -06:00
blk-timeout.c blk-mq: Allow requests to never expire 2015-01-08 08:59:01 -07:00
blk.h blk-mq: fix race between timeout and freeing request 2015-08-15 09:45:21 -06:00
bounce.c block: manipulate bio->bi_flags through helpers 2015-07-29 08:55:20 -06:00
bsg-lib.c bsg: Remove unused function bsg_goose_queue() 2012-12-06 14:33:02 +01:00
bsg.c block: Simplify bsg complete all 2015-02-04 09:57:52 -07:00
cfq-iosched.c Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block 2015-06-25 16:00:17 -07:00
cmdline-parser.c block: remove unrelated header files and export symbol 2014-01-21 20:18:26 -08:00
compat_ioctl.c block, bdi: an active gendisk always has a request_queue associated with it 2014-09-08 10:00:35 -06:00
deadline-iosched.c block: Stop abusing csd.list for fifo_time 2014-02-24 14:46:32 -08:00
elevator.c Merge branch 'for-4.2/writeback' of git://git.kernel.dk/linux-block 2015-06-25 16:00:17 -07:00
genhd.c block: partition: convert percpu ref 2015-07-17 08:41:53 -06:00
ioctl.c block: replace trylock with mutex_lock in blkdev_reread_part() 2015-05-20 09:05:45 -06:00
ioprio.c block: Fix computation of merged request priority 2014-10-31 08:30:43 -06:00
Kconfig block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
Kconfig.iosched blkcg: make CONFIG_BLK_CGROUP bool 2012-03-06 21:27:21 +01:00
Makefile block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00
noop-iosched.c elevator: Fix a race in elevator switching 2013-07-03 13:25:24 +02:00
partition-generic.c block: partition: convert percpu ref 2015-07-17 08:41:53 -06:00
scsi_ioctl.c block: fix bogus EFAULT error from SG_IO ioctl 2015-06-27 11:43:34 -06:00
t10-pi.c block: Add T10 Protection Information functions 2014-09-27 09:14:59 -06:00