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Commit 9ca980dc authored by Paul Mackerras's avatar Paul Mackerras Committed by Benjamin Herrenschmidt
Browse files

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: default avatarPaul Mackerras <paulus@samba.org>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 7ac87abb

arch/powerpc/kernel/smp.c

+14 −4
Original line number Diff line number Diff line
@@ -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

arch/powerpc/platforms/85xx/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

	}

arch/powerpc/platforms/iseries/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/platforms/powermac/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -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,

arch/powerpc/platforms/pseries/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -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,