cpumask: smp_call_function_many()
Impact: Implementation change to remove cpumask_t from stack.
Actually change smp_call_function_mask() to smp_call_function_many().
We avoid cpumasks on the stack in this version.
(S390 has its own version, but that's going away apparently).
We have to do some dancing to figure out if 0 or 1 other cpus are in
the mask supplied and the online mask without allocating a tmp
cpumask. It's still fairly cheap.
We allocate the cpumask at the end of the call_function_data
structure: if allocation fails we fallback to smp_call_function_single
rather than using the baroque quiescing code (which needs a cpumask on
stack).
(Thanks to Hiroshi Shimamoto for spotting several bugs in previous versions!)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: npiggin@suse.de
Cc: axboe@kernel.dk
diff --git a/include/linux/smp.h b/include/linux/smp.h
index 2f85f3b..b824669 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -67,15 +67,16 @@
* Call a function on all other processors
*/
int smp_call_function(void(*func)(void *info), void *info, int wait);
-/* Deprecated: use smp_call_function_many() which uses a cpumask ptr. */
-int smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info,
- int wait);
+void smp_call_function_many(const struct cpumask *mask,
+ void (*func)(void *info), void *info, bool wait);
-static inline void smp_call_function_many(const struct cpumask *mask,
- void (*func)(void *info), void *info,
- int wait)
+/* Deprecated: Use smp_call_function_many which takes a pointer to the mask. */
+static inline int
+smp_call_function_mask(cpumask_t mask, void(*func)(void *info), void *info,
+ int wait)
{
- smp_call_function_mask(*mask, func, info, wait);
+ smp_call_function_many(&mask, func, info, wait);
+ return 0;
}
int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,