From 9ca980dce523760ce04a798470d36fd5aa596b78 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 25 May 2011 23:34:12 +0000 Subject: [PATCH] powerpc: Avoid extra indirect function call in sending IPIs On many platforms (including pSeries), smp_ops->message_pass is always smp_muxed_ipi_message_pass. This changes arch/powerpc/kernel/smp.c so that if smp_ops->message_pass is NULL, it calls smp_muxed_ipi_message_pass directly. This means that a platform doesn't need to set both .message_pass and .cause_ipi, only one of them. It is a slight performance improvement in that it gets rid of an indirect function call at the expense of a predictable conditional branch. Signed-off-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/smp.c | 18 ++++++++++++++---- arch/powerpc/platforms/85xx/smp.c | 2 +- arch/powerpc/platforms/iseries/smp.c | 2 +- arch/powerpc/platforms/powermac/smp.c | 2 +- arch/powerpc/platforms/pseries/smp.c | 2 +- arch/powerpc/platforms/wsp/smp.c | 2 +- 6 files changed, 19 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c index 8ebc6700b98d..2975f64cf310 100644 --- a/arch/powerpc/kernel/smp.c +++ b/arch/powerpc/kernel/smp.c @@ -238,15 +238,25 @@ irqreturn_t smp_ipi_demux(void) } #endif /* CONFIG_PPC_SMP_MUXED_IPI */ +static inline void do_message_pass(int cpu, int msg) +{ + if (smp_ops->message_pass) + smp_ops->message_pass(cpu, msg); +#ifdef CONFIG_PPC_SMP_MUXED_IPI + else + smp_muxed_ipi_message_pass(cpu, msg); +#endif +} + void smp_send_reschedule(int cpu) { if (likely(smp_ops)) - smp_ops->message_pass(cpu, PPC_MSG_RESCHEDULE); + do_message_pass(cpu, PPC_MSG_RESCHEDULE); } void arch_send_call_function_single_ipi(int cpu) { - smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); + do_message_pass(cpu, PPC_MSG_CALL_FUNC_SINGLE); } void arch_send_call_function_ipi_mask(const struct cpumask *mask) @@ -254,7 +264,7 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask) unsigned int cpu; for_each_cpu(cpu, mask) - smp_ops->message_pass(cpu, PPC_MSG_CALL_FUNCTION); + do_message_pass(cpu, PPC_MSG_CALL_FUNCTION); } #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC) @@ -268,7 +278,7 @@ void smp_send_debugger_break(void) for_each_online_cpu(cpu) if (cpu != me) - smp_ops->message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); + do_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK); } #endif diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c index d6a93a10c0f5..8eef8d2b4472 100644 --- a/arch/powerpc/platforms/85xx/smp.c +++ b/arch/powerpc/platforms/85xx/smp.c @@ -236,7 +236,7 @@ void __init mpc85xx_smp_init(void) } if (cpu_has_feature(CPU_FTR_DBELL)) { - smp_85xx_ops.message_pass = smp_muxed_ipi_message_pass; + /* .message_pass defaults to smp_muxed_ipi_message_pass */ smp_85xx_ops.cause_ipi = doorbell_cause_ipi; } diff --git a/arch/powerpc/platforms/iseries/smp.c b/arch/powerpc/platforms/iseries/smp.c index e3265adde5d3..2df48c2287bd 100644 --- a/arch/powerpc/platforms/iseries/smp.c +++ b/arch/powerpc/platforms/iseries/smp.c @@ -75,7 +75,7 @@ static void __devinit smp_iSeries_setup_cpu(int nr) } static struct smp_ops_t iSeries_smp_ops = { - .message_pass = smp_muxed_ipi_message_pass, + .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ .cause_ipi = smp_iSeries_cause_ipi, .probe = smp_iSeries_probe, .kick_cpu = smp_iSeries_kick_cpu, diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c index db092d7c4c5b..d15fca322978 100644 --- a/arch/powerpc/platforms/powermac/smp.c +++ b/arch/powerpc/platforms/powermac/smp.c @@ -447,7 +447,7 @@ void __init smp_psurge_give_timebase(void) /* PowerSurge-style Macs */ struct smp_ops_t psurge_smp_ops = { - .message_pass = smp_muxed_ipi_message_pass, + .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ .cause_ipi = smp_psurge_cause_ipi, .probe = smp_psurge_probe, .kick_cpu = smp_psurge_kick_cpu, diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index fbffd7e47ab8..84dafd33edc5 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -207,7 +207,7 @@ static struct smp_ops_t pSeries_mpic_smp_ops = { }; static struct smp_ops_t pSeries_xics_smp_ops = { - .message_pass = smp_muxed_ipi_message_pass, + .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ .cause_ipi = NULL, /* Filled at runtime by xics_smp_probe() */ .probe = xics_smp_probe, .kick_cpu = smp_pSeries_kick_cpu, diff --git a/arch/powerpc/platforms/wsp/smp.c b/arch/powerpc/platforms/wsp/smp.c index 9d20fa9d3710..71bd105f3863 100644 --- a/arch/powerpc/platforms/wsp/smp.c +++ b/arch/powerpc/platforms/wsp/smp.c @@ -75,7 +75,7 @@ static int __init smp_a2_probe(void) } static struct smp_ops_t a2_smp_ops = { - .message_pass = smp_muxed_ipi_message_pass, + .message_pass = NULL, /* Use smp_muxed_ipi_message_pass */ .cause_ipi = doorbell_cause_ipi, .probe = smp_a2_probe, .kick_cpu = smp_a2_kick_cpu, -- 2.11.0