linux-kernel - [PATCH RFC 12/12] x86/pvticketlock: use callee-save for unlock

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Message-Id: <20100717004855.D84F4A3C51@abulafia.goop.org>
Date:	Tue, 13 Jul 2010 17:56:01 -0700
From:	Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Nick Piggin <nickpiggin@...oo.com.au>,
	Peter Zijlstra <peterz@...radead.org>,
	Jan Beulich <JBeulich@...ell.com>, Avi Kivity <avi@...hat.com>,
	Xen-devel <xen-devel@...ts.xensource.com>
Subject: [PATCH RFC 12/12] x86/pvticketlock: use callee-save for unlock_kick as well

The unlock code is typically inlined throughout the kernel, so its useful
to make sure there's minimal register pressure overhead from the presence
of the unlock_tick pvop call.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
---
 arch/x86/include/asm/paravirt.h       |    2 +-
 arch/x86/include/asm/paravirt_types.h |    2 +-
 arch/x86/kernel/paravirt-spinlocks.c  |    2 +-
 arch/x86/xen/spinlock.c               |    3 ++-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index d02c5fe..487f965 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -738,7 +738,7 @@ static inline void __ticket_lock_spinning(struct arch_spinlock *lock, unsigned t
 
 static inline void ____ticket_unlock_kick(struct arch_spinlock *lock, unsigned ticket)
 {
-	PVOP_VCALL2(pv_lock_ops.unlock_kick, lock, ticket);
+	PVOP_VCALLEE2(pv_lock_ops.unlock_kick, lock, ticket);
 }
 
 #endif
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index b8205c4..be6f2a4 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -321,7 +321,7 @@ struct pv_mmu_ops {
 struct arch_spinlock;
 struct pv_lock_ops {
 	struct paravirt_callee_save lock_spinning;
-	void (*unlock_kick)(struct arch_spinlock *lock, unsigned ticket);
+	struct paravirt_callee_save unlock_kick;
 };
 
 /* This contains all the paravirt structures: we get a convenient
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 4251c1d..efad219 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -10,7 +10,7 @@
 struct pv_lock_ops pv_lock_ops = {
 #ifdef CONFIG_SMP
 	.lock_spinning = __PV_IS_CALLEE_SAVE(paravirt_nop),
-	.unlock_kick = paravirt_nop,
+	.unlock_kick = __PV_IS_CALLEE_SAVE(paravirt_nop),
 #endif
 };
 EXPORT_SYMBOL(pv_lock_ops);
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 598e126..d07eff3 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -158,6 +158,7 @@ static void xen_unlock_kick(struct arch_spinlock *lock, unsigned next)
 		}
 	}
 }
+PV_CALLEE_SAVE_REGS_THUNK(xen_unlock_kick);
 
 static irqreturn_t dummy_handler(int irq, void *dev_id)
 {
@@ -194,7 +195,7 @@ void xen_uninit_lock_cpu(int cpu)
 void __init xen_init_spinlocks(void)
 {
 	pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
-	pv_lock_ops.unlock_kick = xen_unlock_kick;
+	pv_lock_ops.unlock_kick = PV_CALLEE_SAVE(xen_unlock_kick);
 }
 
 #ifdef CONFIG_XEN_DEBUG_FS
-- 
1.7.1.1

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