linux_dsm_epyc7002/include
Hou Tao e6b1a44ecc locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count
The __this_cpu*() accessors are (in general) IRQ-unsafe which, given
that percpu-rwsem is a blocking primitive, should be just fine.

However, file_end_write() is used from IRQ context and will cause
load-store issues on architectures where the per-cpu accessors are not
natively irq-safe.

Fix it by using the IRQ-safe this_cpu_*() for operations on
read_count. This will generate more expensive code on a number of
platforms, which might cause a performance regression for some of the
other percpu-rwsem users.

If any such is reported, we can consider alternative solutions.

Fixes: 70fe2f4815 ("aio: fix freeze protection of aio writes")
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lkml.kernel.org/r/20200915140750.137881-1-houtao1@huawei.com
2020-09-16 16:26:56 +02:00
..
acpi
asm-generic iomap: constify ioreadX() iomem argument (as in generic implementation) 2020-08-14 19:56:57 -07:00
clocksource include/: replace HTTP links with HTTPS ones 2020-08-12 10:57:59 -07:00
crypto mm, treewide: rename kzfree() to kfree_sensitive() 2020-08-07 11:33:22 -07:00
drm Linux 5.9-rc2 2020-08-25 11:00:02 +02:00
dt-bindings Here's some more updates that missed the last pull request because I 2020-08-12 12:19:49 -07:00
keys
kunit
kvm
linux locking/percpu-rwsem: Use this_cpu_{inc,dec}() for read_count 2020-09-16 16:26:56 +02:00
math-emu treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
media media updates for v5.9-rc1 2020-08-07 13:00:53 -07:00
memory
misc
net ipv6: some fixes for ipv6_dev_find() 2020-08-18 15:58:53 -07:00
pcmcia
ras
rdma RDMA 5.9 merge window pull request 2020-08-06 16:43:36 -07:00
scsi
soc include/: replace HTTP links with HTTPS ones 2020-08-12 10:57:59 -07:00
sound
target
trace powerpc fixes for 5.9 #4 2020-08-30 10:56:12 -07:00
uapi Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf 2020-08-21 12:54:50 -07:00
vdso
video
xen xen: branch for v5.9-rc3 2020-08-29 12:44:30 -07:00