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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 <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Paul Mackerras 2011-05-25 23:34:12 +00:00 committed by Benjamin Herrenschmidt
parent 7ac87abb81
commit 9ca980dce5
6 changed files with 19 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
arch/powerpc/kernel/smp.c
View File

@ -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

2
arch/powerpc/platforms/85xx/smp.c
View File

@ -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;
}

2
arch/powerpc/platforms/iseries/smp.c
View File

@ -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,

2
arch/powerpc/platforms/powermac/smp.c
View File

@ -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,

2
arch/powerpc/platforms/pseries/smp.c
View File

@ -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,

2
arch/powerpc/platforms/wsp/smp.c
View File

@ -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,