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-rw-r--r--kernel/smp.c156
1 files changed, 88 insertions, 68 deletions
diff --git a/kernel/smp.c b/kernel/smp.c
index aeb0adfa0606..c8a5a1facc1a 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -608,12 +608,28 @@ call:
}
EXPORT_SYMBOL_GPL(smp_call_function_any);
+/*
+ * Flags to be used as scf_flags argument of smp_call_function_many_cond().
+ *
+ * %SCF_WAIT: Wait until function execution is completed
+ * %SCF_RUN_LOCAL: Run also locally if local cpu is set in cpumask
+ */
+#define SCF_WAIT (1U << 0)
+#define SCF_RUN_LOCAL (1U << 1)
+
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)
+ unsigned int scf_flags,
+ smp_cond_func_t cond_func)
{
+ int cpu, last_cpu, this_cpu = smp_processor_id();
struct call_function_data *cfd;
- int cpu, next_cpu, this_cpu = smp_processor_id();
+ bool wait = scf_flags & SCF_WAIT;
+ bool run_remote = false;
+ bool run_local = false;
+ int nr_cpus = 0;
+
+ lockdep_assert_preemption_disabled();
/*
* Can deadlock when called with interrupts disabled.
@@ -621,8 +637,9 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
* send smp call function interrupt to this cpu and as such deadlocks
* can't happen.
*/
- WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
- && !oops_in_progress && !early_boot_irqs_disabled);
+ if (cpu_online(this_cpu) && !oops_in_progress &&
+ !early_boot_irqs_disabled)
+ lockdep_assert_irqs_enabled();
/*
* When @wait we can deadlock when we interrupt between llist_add() and
@@ -632,60 +649,65 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
*/
WARN_ON_ONCE(!in_task());
- /* Try to fastpath. So, what's a CPU they want? Ignoring this one. */
+ /* Check if we need local execution. */
+ if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask))
+ run_local = true;
+
+ /* Check if we need remote execution, i.e., any CPU excluding this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
if (cpu == this_cpu)
cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
+ if (cpu < nr_cpu_ids)
+ run_remote = true;
- /* No online cpus? We're done. */
- if (cpu >= nr_cpu_ids)
- return;
-
- /* Do we have another CPU which isn't us? */
- next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
- if (next_cpu == this_cpu)
- next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);
-
- /* Fastpath: do that cpu by itself. */
- if (next_cpu >= nr_cpu_ids) {
- if (!cond_func || cond_func(cpu, info))
- smp_call_function_single(cpu, func, info, wait);
- return;
- }
-
- cfd = this_cpu_ptr(&cfd_data);
+ if (run_remote) {
+ cfd = this_cpu_ptr(&cfd_data);
+ cpumask_and(cfd->cpumask, mask, cpu_online_mask);
+ __cpumask_clear_cpu(this_cpu, cfd->cpumask);
- cpumask_and(cfd->cpumask, mask, cpu_online_mask);
- __cpumask_clear_cpu(this_cpu, cfd->cpumask);
-
- /* Some callers race with other cpus changing the passed mask */
- if (unlikely(!cpumask_weight(cfd->cpumask)))
- return;
+ cpumask_clear(cfd->cpumask_ipi);
+ for_each_cpu(cpu, cfd->cpumask) {
+ call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
- cpumask_clear(cfd->cpumask_ipi);
- 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;
- if (cond_func && !cond_func(cpu, info))
- continue;
-
- csd_lock(csd);
- if (wait)
- csd->node.u_flags |= CSD_TYPE_SYNC;
- csd->func = func;
- csd->info = info;
+ csd_lock(csd);
+ if (wait)
+ csd->node.u_flags |= CSD_TYPE_SYNC;
+ csd->func = func;
+ csd->info = info;
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
- csd->node.src = smp_processor_id();
- csd->node.dst = cpu;
+ csd->node.src = smp_processor_id();
+ csd->node.dst = cpu;
#endif
- if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu)))
- __cpumask_set_cpu(cpu, cfd->cpumask_ipi);
+ if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
+ __cpumask_set_cpu(cpu, cfd->cpumask_ipi);
+ nr_cpus++;
+ last_cpu = cpu;
+ }
+ }
+
+ /*
+ * Choose the most efficient way to send an IPI. Note that the
+ * number of CPUs might be zero due to concurrent changes to the
+ * provided mask.
+ */
+ if (nr_cpus == 1)
+ arch_send_call_function_single_ipi(last_cpu);
+ else if (likely(nr_cpus > 1))
+ arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
}
- /* Send a message to all CPUs in the map */
- arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+ if (run_local && (!cond_func || cond_func(this_cpu, info))) {
+ unsigned long flags;
- if (wait) {
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
+ }
+
+ if (run_remote && wait) {
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd;
@@ -696,12 +718,14 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
}
/**
- * smp_call_function_many(): Run a function on a set of other CPUs.
+ * smp_call_function_many(): Run a function on a set of 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.
+ * @flags: Bitmask that controls the operation. If %SCF_WAIT is set, wait
+ * (atomically) until function has completed on other CPUs. If
+ * %SCF_RUN_LOCAL is set, the function will also be run locally
+ * if the local CPU is set in the @cpumask.
*
* If @wait is true, then returns once @func has returned.
*
@@ -712,7 +736,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
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);
+ smp_call_function_many_cond(mask, func, info, wait * SCF_WAIT, NULL);
}
EXPORT_SYMBOL(smp_call_function_many);
@@ -860,16 +884,15 @@ EXPORT_SYMBOL(on_each_cpu);
void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
void *info, bool wait)
{
- int cpu = get_cpu();
+ unsigned int scf_flags;
- smp_call_function_many(mask, func, info, wait);
- if (cpumask_test_cpu(cpu, mask)) {
- unsigned long flags;
- local_irq_save(flags);
- func(info);
- local_irq_restore(flags);
- }
- put_cpu();
+ scf_flags = SCF_RUN_LOCAL;
+ if (wait)
+ scf_flags |= SCF_WAIT;
+
+ preempt_disable();
+ smp_call_function_many_cond(mask, func, info, scf_flags, NULL);
+ preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_mask);
@@ -898,17 +921,14 @@ EXPORT_SYMBOL(on_each_cpu_mask);
void on_each_cpu_cond_mask(smp_cond_func_t cond_func, smp_call_func_t func,
void *info, bool wait, const struct cpumask *mask)
{
- int cpu = get_cpu();
+ unsigned int scf_flags = SCF_RUN_LOCAL;
- 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 (wait)
+ scf_flags |= SCF_WAIT;
- local_irq_save(flags);
- func(info);
- local_irq_restore(flags);
- }
- put_cpu();
+ preempt_disable();
+ smp_call_function_many_cond(mask, func, info, scf_flags, cond_func);
+ preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-01 02:25:00 +0000