Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966267Ab0GQBDN (ORCPT ); Fri, 16 Jul 2010 21:03:13 -0400 Received: from claw.goop.org ([74.207.240.146]:46948 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759576Ab0GQBDH (ORCPT ); Fri, 16 Jul 2010 21:03:07 -0400 Message-Id: <9cbfe46c699d5d09bd989afcb621466292920276.1279328276.git.jeremy.fitzhardinge@citrix.com> In-Reply-To: References: Subject: [PATCH RFC 11/12] x86/pvticketlock: use callee-save for lock_spinning To: Linux Kernel Mailing List Cc: Nick Piggin , Peter Zijlstra , Jan Beulich , Avi Kivity , Xen-devel From: Jeremy Fitzhardinge Date: Fri, 16 Jul 2010 18:03:04 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3068 Lines: 84 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 6370e69..d02c5fe 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -733,7 +733,7 @@ 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 48aed65..b8205c4 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -320,7 +320,7 @@ 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 2f81d5e..598e126 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -140,6 +140,7 @@ 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) { @@ -192,7 +193,7 @@ 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; } -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/