Commit 7d49b28a authored by Rik van Riel's avatar Rik van Riel Committed by Peter Zijlstra
Browse files

smp,cpumask: introduce on_each_cpu_cond_mask 



Introduce a variant of on_each_cpu_cond that iterates only over the
CPUs in a cpumask, in order to avoid making callbacks for every single
CPU in the system when we only need to test a subset.

Cc: npiggin@gmail.com
Cc: mingo@kernel.org
Cc: will.deacon@arm.com
Cc: songliubraving@fb.com
Cc: kernel-team@fb.com
Cc: hpa@zytor.com
Cc: luto@kernel.org
Signed-off-by: default avatarRik van Riel <riel@surriel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-5-riel@surriel.com
parent c3f7f2c7

include/linux/smp.h

+4 −0
Original line number Diff line number Diff line
@@ -53,6 +53,10 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 
		smp_call_func_t func, void *info, bool wait,

		gfp_t gfp_flags);



void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),

		smp_call_func_t func, void *info, bool wait,

		gfp_t gfp_flags, const struct cpumask *mask);



int smp_call_function_single_async(int cpu, call_single_data_t *csd);



#ifdef CONFIG_SMP

kernel/smp.c

+13 −4
Original line number Diff line number Diff line
@@ -669,9 +669,9 @@ EXPORT_SYMBOL(on_each_cpu_mask); 
 * You must not call this function with disabled interrupts or

 * from a hardware interrupt handler or from a bottom half handler.

 */

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),

			smp_call_func_t func, void *info, bool wait,

			gfp_t gfp_flags)

			gfp_t gfp_flags, const struct cpumask *mask)

{

	cpumask_var_t cpus;

	int cpu, ret;
@@ -680,7 +680,7 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 


	if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {

		preempt_disable();

		for_each_online_cpu(cpu)

		for_each_cpu(cpu, mask)

			if (cond_func(cpu, info))

				__cpumask_set_cpu(cpu, cpus);

		on_each_cpu_mask(cpus, func, info, wait);
@@ -692,7 +692,7 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 
		 * just have to IPI them one by one.

		 */

		preempt_disable();

		for_each_online_cpu(cpu)

		for_each_cpu(cpu, mask)

			if (cond_func(cpu, info)) {

				ret = smp_call_function_single(cpu, func,

								info, wait);
@@ -701,6 +701,15 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 
		preempt_enable();

	}

}

EXPORT_SYMBOL(on_each_cpu_cond_mask);



void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

			smp_call_func_t func, void *info, bool wait,

			gfp_t gfp_flags)

{

	on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags,

				cpu_online_mask);

}

EXPORT_SYMBOL(on_each_cpu_cond);



static void do_nothing(void *unused)

kernel/up.c

+11 −3
Original line number Diff line number Diff line
@@ -68,9 +68,9 @@ EXPORT_SYMBOL(on_each_cpu_mask); 
 * Preemption is disabled here to make sure the cond_func is called under the

 * same condtions in UP and SMP.

 */

void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

void on_each_cpu_cond_mask(bool (*cond_func)(int cpu, void *info),

			   smp_call_func_t func, void *info, bool wait,

		      gfp_t gfp_flags)

			   gfp_t gfp_flags, const struct cpumask *mask)

{

	unsigned long flags;
@@ -82,6 +82,14 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info), 
	}

	preempt_enable();

}

EXPORT_SYMBOL(on_each_cpu_cond_mask);



void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),

		      smp_call_func_t func, void *info, bool wait,

		      gfp_t gfp_flags)

{

	on_each_cpu_cond_mask(cond_func, func, info, wait, gfp_flags, NULL);

}

EXPORT_SYMBOL(on_each_cpu_cond);



int smp_call_on_cpu(unsigned int cpu, int (*func)(void *), void *par, bool phys)

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