From mboxrd@z Thu Jan 1 00:00:00 1970 From: Raghavendra K T Subject: [PATCH RFC V11 7/18] x86/pvticketlock: Use callee-save for lock_spinning Date: Mon, 22 Jul 2013 11:48:09 +0530 Message-ID: <20130722061809.24737.51002.sendpatchset@codeblue> References: <20130722061631.24737.75508.sendpatchset@codeblue> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130722061631.24737.75508.sendpatchset@codeblue> 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: gleb@redhat.com, mingo@redhat.com, jeremy@goop.org, x86@kernel.org, konrad.wilk@oracle.com, hpa@zytor.com, pbonzini@redhat.com Cc: gregkh@suse.de, kvm@vger.kernel.org, linux-doc@vger.kernel.org, peterz@infradead.org, drjones@redhat.com, virtualization@lists.linux-foundation.org, andi@firstfloor.org, xen-devel@lists.xensource.com, Raghavendra K T , habanero@linux.vnet.ibm.com, riel@redhat.com, stefano.stabellini@eu.citrix.com, ouyang@cs.pitt.edu, avi.kivity@gmail.com, tglx@linutronix.de, chegu_vinod@hp.com, linux-kernel@vger.kernel.org, srivatsa.vaddagiri@gmail.com, attilio.rao@citrix.com, torvalds@linux-foundation.org List-Id: xen-devel@lists.xenproject.org x86/pvticketlock: Use callee-save for lock_spinning 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 Reviewed-by: Konrad Rzeszutek Wilk Tested-by: Attilio Rao Signed-off-by: Raghavendra K T --- 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 040e72d..7131e12c 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -715,7 +715,7 @@ static inline void __set_fixmap(unsigned /* enum fixed_addresses */ idx, static __always_inline void __ticket_lock_spinning(struct arch_spinlock *lock, __ticket_t ticket) { - PVOP_VCALL2(pv_lock_ops.lock_spinning, lock, ticket); + PVOP_VCALLEE2(pv_lock_ops.lock_spinning, lock, ticket); } static __always_inline void ____ticket_unlock_kick(struct arch_spinlock *lock, diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index d5deb6d..350d017 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -330,7 +330,7 @@ struct arch_spinlock; #include struct pv_lock_ops { - void (*lock_spinning)(struct arch_spinlock *lock, __ticket_t ticket); + struct paravirt_callee_save lock_spinning; void (*unlock_kick)(struct arch_spinlock *lock, __ticket_t 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 ec9183b..b41872b 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -173,6 +173,7 @@ out: local_irq_restore(flags); spin_time_accum_blocked(start); } +PV_CALLEE_SAVE_REGS_THUNK(xen_lock_spinning); static void xen_unlock_kick(struct arch_spinlock *lock, __ticket_t next) { @@ -260,7 +261,7 @@ void __init xen_init_spinlocks(void) return; } - 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; }