Merge branch 'linus' into irq/numa

[safe/jmp/linux-2.6] / arch / x86 / Kconfig

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e03485b..b1d3f60 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -492,6 +492,19 @@ config PARAVIRT
          over full virtualization.  However, when run without a hypervisor
          the kernel is theoretically slower and slightly larger.
 
+config PARAVIRT_SPINLOCKS
+       bool "Paravirtualization layer for spinlocks"
+       depends on PARAVIRT && SMP && EXPERIMENTAL
+       ---help---
+         Paravirtualized spinlocks allow a pvops backend to replace the
+         spinlock implementation with something virtualization-friendly
+         (for example, block the virtual CPU rather than spinning).
+
+         Unfortunately the downside is an up to 5% performance hit on
+         native kernels, with various workloads.
+
+         If you are unsure how to answer this question, answer N.
+
 config PARAVIRT_CLOCK
        bool
        default n