locking/qspinlock: Revert to test-and-set on hypervisors
authorPeter Zijlstra (Intel) <peterz@infradead.org>
Fri, 24 Apr 2015 18:56:36 +0000 (14:56 -0400)
committerIngo Molnar <mingo@kernel.org>
Fri, 8 May 2015 10:36:58 +0000 (12:36 +0200)
commit2aa79af64263190eec610422b07f60e99a7d230a
tree423641cd1ae46f066739d62d743f39c7eb58c5c8
parent2c83e8e9492dc823be1d96d4c5ef75d16d3866a0
locking/qspinlock: Revert to test-and-set on hypervisors

When we detect a hypervisor (!paravirt, see qspinlock paravirt support
patches), revert to a simple test-and-set lock to avoid the horrors
of queue preemption.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <paolo.bonzini@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1429901803-29771-8-git-send-email-Waiman.Long@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/x86/include/asm/qspinlock.h
include/asm-generic/qspinlock.h
kernel/locking/qspinlock.c