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generic-ipi: Add smp_call_function_any()

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Andrew points out that acpi-cpufreq uses cpumask_any, when it really
would prefer to use the same CPU if possible (to avoid an IPI).  In
general, this seems a good idea to offer.

[ tglx: Documented selection preference and Inlined the UP case to
  	avoid the copy of smp_call_function_single() and the extra
  	EXPORT ]

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Zhao Yakui <yakui.zhao@intel.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: "Zhang, Yanmin" <yanmin_zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Rusty Russell 2009-11-17 14:27:27 -08:00 committed by Thomas Gleixner
parent 72f279b256
commit 2ea6dec4a2
2 changed files with 55 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
include/linux/smp.h
View file

@ -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, void __smp_call_function_single(int cpuid, struct call_single_data *data,
int wait); int wait);
int smp_call_function_any(const struct cpumask *mask,
void (*func)(void *info), void *info, int wait);
/* /*
* Generic and arch helpers * 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_prepare_boot_cpu() do {} while (0)
#define smp_call_function_many(mask, func, info, wait) \ #define smp_call_function_many(mask, func, info, wait) \
(up_smp_call_function(func, info)) (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 */ #endif /* !SMP */
/* /*

45
kernel/smp.c
View file

@ -319,6 +319,51 @@ int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
} }
EXPORT_SYMBOL(smp_call_function_single); 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 * __smp_call_function_single(): Run a function on another CPU
* @cpu: The CPU to run on. * @cpu: The CPU to run on.