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Date: Fri, 24 Jan 2020 19:45:22 -0000
From: "tip-bot2 for Sebastian Andrzej Siewior" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Thomas Gleixner <tglx@...utronix.de>,
"Peter Zijlstra (Intel)" <peterz@...radead.org>,
x86 <x86@...nel.org>, LKML <linux-kernel@...r.kernel.org>
Subject: [tip: smp/core] smp: Add a smp_cond_func_t argument to
smp_call_function_many()
The following commit has been merged into the smp/core branch of tip:
Commit-ID: 67719ef25eeb2048b11befa6a757aeb3848b5df1
Gitweb: https://git.kernel.org/tip/67719ef25eeb2048b11befa6a757aeb3848b5df1
Author: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Fri, 17 Jan 2020 10:01:36 +01:00
Committer: Thomas Gleixner <tglx@...utronix.de>
CommitterDate: Fri, 24 Jan 2020 20:40:09 +01:00
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@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Link: https://lore.kernel.org/r/20200117090137.1205765-3-bigeasy@linutronix.de
---
kernel/smp.c | 81 +++++++++++++++++++++++----------------------------
1 file changed, 38 insertions(+), 43 deletions(-)
diff --git a/kernel/smp.c b/kernel/smp.c
index c64044d..e17e634 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -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;
-
- might_sleep_if(gfpflags_allow_blocking(gfp_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();
+ int cpu = get_cpu();
+
+ smp_call_function_many_cond(mask, func, info, wait, cond_func);
+ if (cpumask_test_cpu(cpu, mask) && cond_func(cpu, info)) {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ func(info);
+ local_irq_restore(flags);
}
+ put_cpu();
}
EXPORT_SYMBOL(on_each_cpu_cond_mask);
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