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: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Rik van Riel <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Link: http://lkml.kernel.org/r/[email protected]
ambv · Oct 9, 2018 · 7d49b28 · 7d49b28
1 parent c3f7f2c
commit 7d49b28
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Showing 3 changed files with 28 additions and 7 deletions.
diff --git a/include/linux/smp.h b/include/linux/smp.h
@@ -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

diff --git a/kernel/smp.c b/kernel/smp.c
@@ -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)

diff --git a/kernel/up.c b/kernel/up.c
@@ -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),
-		      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)
 {
 	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)