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smp: Add a smp_cond_func_t argument to smp_call_function_many() 

on_each_cpu_cond_mask() allocates a new CPU mask. The newly allocated
mask is a subset of the provided mask based on the conditional function.

This memory allocation can be avoided by extending smp_call_function_many()
with the conditional function and performing the remote function call based
on the mask and the conditional function.

Rename smp_call_function_many() to smp_call_function_many_cond() and add
the smp_cond_func_t argument. If smp_cond_func_t is provided then it is
used before invoking the function.  Provide smp_call_function_many() with
cond_func set to NULL.  Let on_each_cpu_cond_mask() use
smp_call_function_many_cond().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20200117090137.1205765-3-bigeasy@linutronix.de
This commit is contained in:
Sebastian Andrzej Siewior 2020-01-17 10:01:36 +01:00 committed by Thomas Gleixner
parent 5671d814db
commit 67719ef25e
1 changed files with 36 additions and 41 deletions
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77
kernel/smp.c
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@ -395,22 +395,9 @@ call:
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
/**
* smp_call_function_many(): Run a function on a set of other CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
* If @wait is true, then returns once @func has returned.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. Preemption
* must be disabled when calling this function.
*/
void smp_call_function_many(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
static void smp_call_function_many_cond(const struct cpumask *mask,
smp_call_func_t func, void *info,
bool wait, smp_cond_func_t cond_func)
{
struct call_function_data *cfd;
int cpu, next_cpu, this_cpu = smp_processor_id();
@ -448,7 +435,8 @@ void smp_call_function_many(const struct cpumask *mask,
/* Fastpath: do that cpu by itself. */
if (next_cpu >= nr_cpu_ids) {
smp_call_function_single(cpu, func, info, wait);
if (!cond_func || (cond_func && cond_func(cpu, info)))
smp_call_function_single(cpu, func, info, wait);
return;
}
@ -465,6 +453,9 @@ void smp_call_function_many(const struct cpumask *mask,
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
if (cond_func && !cond_func(cpu, info))
continue;
csd_lock(csd);
if (wait)
csd->flags |= CSD_FLAG_SYNCHRONOUS;
@ -486,6 +477,26 @@ void smp_call_function_many(const struct cpumask *mask,
}
}
}
/**
* smp_call_function_many(): Run a function on a set of other CPUs.
* @mask: The set of cpus to run on (only runs on online subset).
* @func: The function to run. This must be fast and non-blocking.
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
* If @wait is true, then returns once @func has returned.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler. Preemption
* must be disabled when calling this function.
*/
void smp_call_function_many(const struct cpumask *mask,
smp_call_func_t func, void *info, bool wait)
{
smp_call_function_many_cond(mask, func, info, wait, NULL);
}
EXPORT_SYMBOL(smp_call_function_many);
/**
@ -684,33 +695,17 @@ void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, gfp_t gfp_flags,
const struct cpumask *mask)
{
cpumask_var_t cpus;
int cpu, ret;
int cpu = get_cpu();
might_sleep_if(gfpflags_allow_blocking(gfp_flags));
smp_call_function_many_cond(mask, func, info, wait, cond_func);
if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) {
unsigned long flags;
if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
preempt_disable();
for_each_cpu(cpu, mask)
if (cond_func(cpu, info))
__cpumask_set_cpu(cpu, cpus);
on_each_cpu_mask(cpus, func, info, wait);
preempt_enable();
free_cpumask_var(cpus);
} else {
/*
* No free cpumask, bother. No matter, we'll
* just have to IPI them one by one.
*/
preempt_disable();
for_each_cpu(cpu, mask)
if (cond_func(cpu, info)) {
ret = smp_call_function_single(cpu, func,
info, wait);
WARN_ON_ONCE(ret);
}
preempt_enable();
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);