Re: [PATCH v8 10/10] pvqspinlock, x86: Enable qspinlock PV support for XEN
From: Waiman Long
Date: Wed Apr 02 2014 - 16:39:19 EST
On 04/02/2014 10:39 AM, Konrad Rzeszutek Wilk wrote:
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index a70fdeb..451e392 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -229,4 +229,4 @@ config ARCH_USE_QUEUE_SPINLOCK
config QUEUE_SPINLOCK
def_bool y if ARCH_USE_QUEUE_SPINLOCK
- depends on SMP&& (!PARAVIRT_SPINLOCKS || !XEN)
+ depends on SMP
If I read this correctly that means you cannot select any more the old
ticketlocks? As in, if you select CONFIG_PARAVIRT on X86 it will automatically
select ARCH_USE_QUEUE_SPINLOCK which will then enable this by default?
Should the 'def_bool' be selectable?
My initial qspinlock patch allows it to be selectable, but there was
comment that doing so would increase the testing matrix and so made it
less desirable. That was why I made it the default for 64-bit code which
are more likely to be used in large machines which benefit the most from
this patch. 32-bit kernel will still use the ticket lock.
-Longman
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