linux/include
Peter Zijlstra 43b3f02899 locking/qspinlock/x86: Fix performance regression under unaccelerated VMs
Dave ran into horrible performance on a VM without PARAVIRT_SPINLOCKS
set and Linus noted that the test-and-set implementation was retarded.

One should spin on the variable with a load, not a RMW.

While there, remove 'queued' from the name, as the lock isn't queued
at all, but a simple test-and-set.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Dave Chinner <david@fromorbit.com>
Tested-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <Waiman.Long@hp.com>
Cc: stable@vger.kernel.org # v4.2+
Link: http://lkml.kernel.org/r/20150904152523.GR18673@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-11 07:49:42 +02:00
..
acpi
asm-generic locking/qspinlock/x86: Fix performance regression under unaccelerated VMs 2015-09-11 07:49:42 +02:00
clocksource
crypto
drm
dt-bindings
keys
kvm
linux locking/static_keys: Fix a silly typo 2015-09-08 09:02:17 +02:00
math-emu
media
memory
misc
net net: sched: fix refcount imbalance in actions 2015-07-30 14:20:39 -07:00
pcmcia
ras
rdma
rxrpc
scsi
soc
sound
target iscsi-target: Fix iscsit_start_kthreads failure OOPs 2015-07-24 14:19:43 -07:00
trace
uapi sound fixes for 4.2-rc5 2015-07-31 17:00:25 -07:00
video
xen
Kbuild