From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: [PATCH 10/14] x86/pvticketlock: use callee-save for lock_spinning Date: Tue, 16 Nov 2010 13:08:41 -0800 Message-ID: <598aba88fd8411b063884264e1521e8e64b3cb15.1289940821.git.jeremy.fitzhardinge__47235.2506164045$1289944572$gmane$org@citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: In-Reply-To: References: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Peter Zijlstra Cc: Xen-devel , Mathieu Desnoyers , Nick Piggin , Srivatsa Vaddagiri , Linux Kernel Mailing List , Jan Beulich , Eric Dumazet , Jeremy Fitzhardinge , Avi Kivity , "H. Peter Anvin" , =?UTF-8?q?Am=C3=A9rico=20Wang?= , Linux Virtualization List-Id: virtualization@lists.linuxfoundation.org From: Jeremy Fitzhardinge Although the lock_spinning calls in the spinlock code are on the uncommon path, their presence can cause the compiler to generate many more register save/restores in the function pre/postamble, which is in the fast path. To avoid this, convert it to using the pvops callee-save calling convention, which defers all the save/restores until the actual function is called, keeping the fastpath clean. Signed-off-by: Jeremy Fitzhardinge --- 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 c864775..6f275ca 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -719,7 +719,7 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx, static inline void __ticket_lock_spinning(struct arch_spinlock *lock, unsigned ticket) { - PVOP_VCALL2(pv_lock_ops.lock_spinning, lock, ticket); + PVOP_VCALLEE2(pv_lock_ops.lock_spinning, lock, ticket); } static inline void ____ticket_unlock_kick(struct arch_spinlock *lock, unsigned ticket) diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 1078474..53f249a 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -315,7 +315,7 @@ struct pv_mmu_ops { struct arch_spinlock; struct pv_lock_ops { - void (*lock_spinning)(struct arch_spinlock *lock, unsigned ticket); + struct paravirt_callee_save lock_spinning; void (*unlock_kick)(struct arch_spinlock *lock, unsigned ticket); }; diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c index c2e010e..4251c1d 100644 --- a/arch/x86/kernel/paravirt-spinlocks.c +++ b/arch/x86/kernel/paravirt-spinlocks.c @@ -9,7 +9,7 @@ struct pv_lock_ops pv_lock_ops = { #ifdef CONFIG_SMP - .lock_spinning = paravirt_nop, + .lock_spinning = __PV_IS_CALLEE_SAVE(paravirt_nop), .unlock_kick = paravirt_nop, #endif }; diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 5feb897..c31c5a3 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -137,6 +137,7 @@ out: w->lock = NULL; spin_time_accum_blocked(start); } +PV_CALLEE_SAVE_REGS_THUNK(xen_lock_spinning); static void xen_unlock_kick(struct arch_spinlock *lock, unsigned next) { @@ -189,7 +190,7 @@ void xen_uninit_lock_cpu(int cpu) void __init xen_init_spinlocks(void) { - pv_lock_ops.lock_spinning = xen_lock_spinning; + pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning); pv_lock_ops.unlock_kick = xen_unlock_kick; } -- 1.7.2.3