linux/include
Jan Kara 34e0a279a9 block: do not reverse request order when flushing plug list
Commit 26fed4ac4e ("block: flush plug based on hardware and software
queue order") changed flushing of plug list to submit requests one
device at a time. However while doing that it also started using
list_add_tail() instead of list_add() used previously thus effectively
submitting requests in reverse order. Also when forming a rq_list with
remaining requests (in case two or more devices are used), we
effectively reverse the ordering of the plug list for each device we
process. Submitting requests in reverse order has negative impact on
performance for rotational disks (when BFQ is not in use). We observe
10-25% regression in random 4k write throughput, as well as ~20%
regression in MariaDB OLTP benchmark on rotational storage on btrfs
filesystem.

Fix the problem by preserving ordering of the plug list when inserting
requests into the queuelist as well as by appending to requeue_list
instead of prepending to it.

Fixes: 26fed4ac4e ("block: flush plug based on hardware and software queue order")
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230313093002.11756-1-jack@suse.cz
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-03-14 09:25:50 -06:00
..
acpi Remove Intel compiler support 2023-03-05 10:49:37 -08:00
asm-generic Driver core changes for 6.3-rc1 2023-02-24 12:58:55 -08:00
clocksource
crypto crypto: api - Use data directly in completion function 2023-02-13 18:35:14 +08:00
drm Driver core changes for 6.3-rc1 2023-02-24 12:58:55 -08:00
dt-bindings ARM: SoC drivers for 6.3 2023-02-27 10:04:49 -08:00
keys
kunit kunit: Expose 'static stub' API to redirect functions 2023-02-08 14:28:17 -07:00
kvm KVM/riscv changes for 6.3 2023-02-15 12:33:28 -05:00
linux block: do not reverse request order when flushing plug list 2023-03-14 09:25:50 -06:00
math-emu
media media updates for v6.3-rc1 2023-02-26 11:47:26 -08:00
memory
misc
net sctp: add a refcnt in sctp_stream_priorities to avoid a nested loop 2023-02-23 12:59:40 -08:00
pcmcia
ras
rdma RDMA/umem: Remove unused 'work' member from struct ib_umem 2023-02-12 20:25:25 +02:00
rv
scsi SCSI misc on 20230303 2023-03-03 14:41:50 -08:00
soc net: mscc: ocelot: un-export unused regmap symbols 2023-02-06 22:33:15 -08:00
sound sound fixes for 6.3-rc1 2023-03-04 10:53:59 -08:00
target
trace f2fs-for-6.3-rc1 2023-02-27 16:18:51 -08:00
uapi SCSI misc on 20230303 2023-03-03 14:41:50 -08:00
ufs SCSI misc on 20230303 2023-03-03 14:41:50 -08:00
vdso
video
xen Driver core changes for 6.3-rc1 2023-02-24 12:58:55 -08:00