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Commit 9a371934 authored by Rusty Russell's avatar Rusty Russell Committed by Benjamin Herrenschmidt
Browse files

powerpc: Make sysfs code use smp_call_function_single 



Impact: performance improvement

This fixes 'powerpc: avoid cpumask games in arch/powerpc/kernel/sysfs.c'
which talked about using smp_call_function_single, but actually used
work_on_cpu (an older version of the patch).

Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent c5785f9e

arch/powerpc/kernel/sysfs.c

+6 −25
Original line number Original line Diff line number Diff line
@@ -134,36 +134,16 @@ void ppc_enable_pmcs(void) 
}

}

EXPORT_SYMBOL(ppc_enable_pmcs);

EXPORT_SYMBOL(ppc_enable_pmcs);





#if defined(CONFIG_6xx) || defined(CONFIG_PPC64)

/* XXX convert to rusty's on_one_cpu */

static unsigned long run_on_cpu(unsigned long cpu,

			        unsigned long (*func)(unsigned long),

				unsigned long arg)

{

	cpumask_t old_affinity = current->cpus_allowed;

	unsigned long ret;



	/* should return -EINVAL to userspace */

	if (set_cpus_allowed(current, cpumask_of_cpu(cpu)))

		return 0;



	ret = func(arg);



	set_cpus_allowed(current, old_affinity);



	return ret;

}

#endif





#define SYSFS_PMCSETUP(NAME, ADDRESS) \

#define SYSFS_PMCSETUP(NAME, ADDRESS) \

static unsigned long read_##NAME(unsigned long junk) \

static void read_##NAME(void *val) \

{ \

{ \

	return mfspr(ADDRESS); \

	mtspr(ADDRESS, *(unsigned long *)val);	\

} \

} \

static unsigned long write_##NAME(unsigned long val) \

static unsigned long write_##NAME(unsigned long val) \

{ \

{ \

	ppc_enable_pmcs(); \

	ppc_enable_pmcs(); \

	mtspr(ADDRESS, val); \

	mtspr(ADDRESS, *(unsigned long *)val);	\

	return 0; \

	return 0; \

} \

} \

static ssize_t show_##NAME(struct sys_device *dev, \

static ssize_t show_##NAME(struct sys_device *dev, \
@@ -171,7 +151,8 @@ static ssize_t show_##NAME(struct sys_device *dev, \ 
			char *buf) \

			char *buf) \

{ \

{ \

	struct cpu *cpu = container_of(dev, struct cpu, sysdev); \

	struct cpu *cpu = container_of(dev, struct cpu, sysdev); \

	unsigned long val = run_on_cpu(cpu->sysdev.id, read_##NAME, 0); \

	unsigned long val; \

	smp_call_function_single(cpu->sysdev.id, read_##NAME, &val, 1);	\

	return sprintf(buf, "%lx\n", val); \

	return sprintf(buf, "%lx\n", val); \

} \

} \

static ssize_t __used \

static ssize_t __used \
@@ -183,7 +164,7 @@ static ssize_t __used \ 
	int ret = sscanf(buf, "%lx", &val); \

	int ret = sscanf(buf, "%lx", &val); \

	if (ret != 1) \

	if (ret != 1) \

		return -EINVAL; \

		return -EINVAL; \

	run_on_cpu(cpu->sysdev.id, write_##NAME, val); \

	smp_call_function_single(cpu->sysdev.id, write_##NAME, &val, 1); \

	return count; \

	return count; \

}

}