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Add helper macros to iterate over available CPUs in the system.

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CPU_FOREACH(i) iterates over the CPU IDs of all available CPUs.  The
CPU_FIRST() and CPU_NEXT(i) macros can also be used to iterate over
available CPU IDs.  CPU_NEXT(i) wraps around to CPU_FIRST() rather than
returning some sort of terminator.

Requested by:	rwatson
Reviewed by:	attilio
This commit is contained in:
John Baldwin 2010-06-11 15:56:18 +00:00
parent 9124d0d6a3
commit e762f66672
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=209050
1 changed files with 38 additions and 0 deletions
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38
sys/sys/smp.h
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@ -91,6 +91,44 @@ extern cpumask_t all_cpus;
*/
#define CPU_ABSENT(x_cpu) ((all_cpus & (1 << (x_cpu))) == 0)
/*
* Macros to iterate over non-absent CPUs. CPU_FOREACH() takes an
* integer iterator and iterates over the available set of CPUs.
* CPU_FIRST() returns the id of the first non-absent CPU. CPU_NEXT()
* returns the id of the next non-absent CPU. It will wrap back to
* CPU_FIRST() once the end of the list is reached. The iterators are
* currently implemented via inline functions.
*/
#define CPU_FOREACH(i) \
for ((i) = 0; (i) <= mp_maxid; (i)++) \
if (!CPU_ABSENT((i)))
static __inline int
cpu_first(void)
{
int i;
for (i = 0;; i++)
if (!CPU_ABSENT(i))
return (i);
}
static __inline int
cpu_next(int i)
{
for (;;) {
i++;
if (i > mp_maxid)
i = 0;
if (!CPU_ABSENT(i))
return (i);
}
}
#define CPU_FIRST() cpu_first()
#define CPU_NEXT(i) cpu_next((i))
#ifdef SMP
/*
* Machine dependent functions used to initialize MP support.