This is a note to let you know that I've just added the patch titled
locking/qspinlock/x86: Only emit the test-and-set fallback when building guest support
to the 4.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
locking-qspinlock-x86-only-emit-the-test-and-set-fallback-when-building-guest-support.patch
and it can be found in the queue-4.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a6b277857fd2c990bc208ca1958d3f34d26052f7 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Sat, 5 Sep 2015 16:55:05 +0200
Subject: locking/qspinlock/x86: Only emit the test-and-set fallback when building guest support
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
commit a6b277857fd2c990bc208ca1958d3f34d26052f7 upstream.
Only emit the test-and-set fallback for Hypervisors lacking
PARAVIRT_SPINLOCKS support when building for guests.
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h
index 8dde3bdc4a05..eaba08076030 100644
--- a/arch/x86/include/asm/qspinlock.h
+++ b/arch/x86/include/asm/qspinlock.h
@@ -39,8 +39,8 @@ static inline void queued_spin_unlock(struct qspinlock *lock)
}
#endif
+#ifdef CONFIG_PARAVIRT
#define virt_spin_lock virt_spin_lock
-
static inline bool virt_spin_lock(struct qspinlock *lock)
{
if (!static_cpu_has(X86_FEATURE_HYPERVISOR))
@@ -59,6 +59,7 @@ static inline bool virt_spin_lock(struct qspinlock *lock)
return true;
}
+#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>
Patches currently in stable-queue which might be from peterz@xxxxxxxxxxxxx are
queue-4.2/time-fix-timekeeping_freqadjust-s-incorrect-use-of-abs-instead-of-abs64.patch
queue-4.2/perf-x86-intel-fix-constraint-access.patch
queue-4.2/sched-access-local-runqueue-directly-in-single_task_running.patch
queue-4.2/locking-qspinlock-x86-only-emit-the-test-and-set-fallback-when-building-guest-support.patch
queue-4.2/locking-qspinlock-x86-fix-performance-regression-under-unaccelerated-vms.patch
--
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