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Subject[PATCH 4/7] smp,cpumask: introduce on_each_cpu_cond_mask
Date
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.

Signed-off-by: Rik van Riel <riel@surriel.com>
---
include/linux/smp.h | 4 ++++
kernel/smp.c | 17 +++++++++++++----
kernel/up.c | 14 +++++++++++---
3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/include/linux/smp.h b/include/linux/smp.h
index 9fb239e12b82..a56f08ff3097 100644
--- 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
index 2dbc842dd385..f4cf1b0bb3b8 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -667,9 +667,9 @@ 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;
@@ -678,7 +678,7 @@ 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);
@@ -690,7 +690,7 @@ 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);
@@ -699,6 +699,15 @@ 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
index 42c46bf3e0a5..ff536f9cc8a2 100644
--- 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)
--
2.17.1
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