linux/include
Mike Christie 7324f47d42 scsi: target: Replace lun_tg_pt_gp_lock with rcu in I/O path
We are only holding the lun_tg_pt_gp_lock in target_alua_state_check() to
make sure tg_pt_gp is not freed from under us while we copy the state,
delay, ID values. We can instead use RCU here to access the tg_pt_gp.

With this patch IOPs can increase up to 10% for jobs like:

  fio  --filename=/dev/sdX  --direct=1 --rw=randrw --bs=4k \
    --ioengine=libaio --iodepth=64  --numjobs=N

when there are multiple sessions (running that fio command to each /dev/sdX
or using multipath and there are over 8 paths), or more than 8 queues for
the loop or vhost with multiple threads case and numjobs > 8.

Link: https://lore.kernel.org/r/20210930020422.92578-5-michael.christie@oracle.com
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2021-10-18 22:38:36 -04:00
..
acpi Merge branches 'pm-cpufreq', 'pm-sleep' and 'pm-em' 2021-09-10 20:26:08 +02:00
asm-generic ARM development updates for 5.15: 2021-09-09 13:25:49 -07:00
clocksource
crypto
drm
dt-bindings linux-watchdog 5.15-rc1 tag 2021-09-07 13:52:46 -07:00
keys
kunit
kvm
linux scsi: ata: Switch to attribute groups 2021-10-16 21:45:52 -04:00
math-emu
media
memory
misc
net
pcmcia
ras
rdma
scsi scsi: core: Remove two host template members that are no longer used 2021-10-16 21:45:59 -04:00
soc
sound
target scsi: target: Replace lun_tg_pt_gp_lock with rcu in I/O path 2021-10-18 22:38:36 -04:00
trace Merge branch 'akpm' (patches from Andrew) 2021-09-08 12:55:35 -07:00
uapi virtio,vdpa,vhost: features, fixes 2021-09-11 14:48:42 -07:00
vdso
video
xen