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Date: Wed, 02 May 2012 15:37:42 +0530 From: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com> To: Jeremy Fitzhardinge <jeremy@...p.org>, Greg Kroah-Hartman <gregkh@...e.de>, Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>, "H. Peter Anvin" <hpa@...or.com>, Avi Kivity <avi@...hat.com>, X86 <x86@...nel.org>, Gleb Natapov <gleb@...hat.com>, Ingo Molnar <mingo@...hat.com>, Marcelo Tosatti <mtosatti@...hat.com> Cc: Attilio Rao <attilio.rao@...rix.com>, Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>, linux-doc@...r.kernel.org, Virtualization <virtualization@...ts.linux-foundation.org>, Xen Devel <xen-devel@...ts.xensource.com>, Linus Torvalds <torvalds@...ux-foundation.org>, KVM <kvm@...r.kernel.org>, Andi Kleen <andi@...stfloor.org>, Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>, Stefano Stabellini <stefano.stabellini@...citrix.com>, Stephan Diestelhorst <stephan.diestelhorst@....com>, LKML <linux-kernel@...r.kernel.org> Subject: [PATCH RFC V8 7/17] x86/pvticketlock: Use callee-save for lock_spinning From: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com> 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 <jeremy.fitzhardinge@...rix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com> Tested-by: Attilio Rao <attilio.rao@...rix.com> Signed-off-by: Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.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 4bcd146..9769096 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -754,7 +754,7 @@ 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 005e24d..5e0c138 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 <asm/spinlock_types.h> 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 c4886dc..c47a8d1 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -171,6 +171,7 @@ 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) { @@ -230,7 +231,7 @@ 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; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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