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: Rik van Riel <riel@surriel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180926035844.1420-5-riel@surriel.com
diff --git a/kernel/smp.c b/kernel/smp.c
index a7d4f9f..163c451 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -669,9 +669,9 @@
* 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 @@
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 @@
* 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 @@
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)