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authorLinus Torvalds <torvalds@linux-foundation.org>2009-12-05 09:49:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-05 09:49:46 -0800
commit9b269d4034c7855ac34f0985cc55ee29bd80e80a (patch)
treeec6c7f54fea5ecfb23eb5ec287732b92924012aa
parent7b626acb8f983eb83b396ab96cc24b18d635d487 (diff)
parent2ea6dec4a22a6f66f6633876212fd4d195cf8277 (diff)
Merge branch 'core-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-ipi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: generic-ipi: Add smp_call_function_any() generic-ipi: Fix misleading smp_call_function*() description
-rw-r--r--include/linux/smp.h11
-rw-r--r--kernel/smp.c56
2 files changed, 58 insertions, 9 deletions
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 39c64bae776d..7a0570e6a596 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -76,6 +76,9 @@ void smp_call_function_many(const struct cpumask *mask,
void __smp_call_function_single(int cpuid, struct call_single_data *data,
int wait);
+int smp_call_function_any(const struct cpumask *mask,
+ void (*func)(void *info), void *info, int wait);
+
/*
* Generic and arch helpers
*/
@@ -137,9 +140,15 @@ static inline void smp_send_reschedule(int cpu) { }
#define smp_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \
(up_smp_call_function(func, info))
-static inline void init_call_single_data(void)
+static inline void init_call_single_data(void) { }
+
+static inline int
+smp_call_function_any(const struct cpumask *mask, void (*func)(void *info),
+ void *info, int wait)
{
+ return smp_call_function_single(0, func, info, wait);
}
+
#endif /* !SMP */
/*
diff --git a/kernel/smp.c b/kernel/smp.c
index c9d1c7835c2f..a8c76069cf50 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -265,9 +265,7 @@ static DEFINE_PER_CPU(struct call_single_data, csd_data);
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait until function has completed on other CPUs.
*
- * Returns 0 on success, else a negative status code. Note that @wait
- * will be implicitly turned on in case of allocation failures, since
- * we fall back to on-stack allocation.
+ * Returns 0 on success, else a negative status code.
*/
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int wait)
@@ -321,6 +319,51 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
}
EXPORT_SYMBOL(smp_call_function_single);
+/*
+ * smp_call_function_any - Run a function on any of the given cpus
+ * @mask: The mask of cpus it can run on.
+ * @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 until function has completed.
+ *
+ * Returns 0 on success, else a negative status code (if no cpus were online).
+ * Note that @wait will be implicitly turned on in case of allocation failures,
+ * since we fall back to on-stack allocation.
+ *
+ * Selection preference:
+ * 1) current cpu if in @mask
+ * 2) any cpu of current node if in @mask
+ * 3) any other online cpu in @mask
+ */
+int smp_call_function_any(const struct cpumask *mask,
+ void (*func)(void *info), void *info, int wait)
+{
+ unsigned int cpu;
+ const struct cpumask *nodemask;
+ int ret;
+
+ /* Try for same CPU (cheapest) */
+ cpu = get_cpu();
+ if (cpumask_test_cpu(cpu, mask))
+ goto call;
+
+ /* Try for same node. */
+ nodemask = cpumask_of_node(cpu);
+ for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
+ cpu = cpumask_next_and(cpu, nodemask, mask)) {
+ if (cpu_online(cpu))
+ goto call;
+ }
+
+ /* Any online will do: smp_call_function_single handles nr_cpu_ids. */
+ cpu = cpumask_any_and(mask, cpu_online_mask);
+call:
+ ret = smp_call_function_single(cpu, func, info, wait);
+ put_cpu();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_function_any);
+
/**
* __smp_call_function_single(): Run a function on another CPU
* @cpu: The CPU to run on.
@@ -355,9 +398,7 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
* @wait: If true, wait (atomically) until function has completed
* on other CPUs.
*
- * If @wait is true, then returns once @func has returned. Note that @wait
- * will be implicitly turned on in case of allocation failures, since
- * we fall back to on-stack allocation.
+ * 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
@@ -443,8 +484,7 @@ EXPORT_SYMBOL(smp_call_function_many);
* Returns 0.
*
* If @wait is true, then returns once @func has returned; otherwise
- * it returns just before the target cpu calls @func. In case of allocation
- * failure, @wait will be implicitly turned on.
+ * it returns just before the target cpu calls @func.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler.