99d8670525
These APIs take logical cpu number as input
Change cpu_first_thread_in_core() to cpu_first_thread_sibling()
Change cpu_last_thread_in_core() to cpu_last_thread_sibling()
These APIs convert core number (index) to logical cpu/thread numbers
Add cpu_first_thread_of_core(int core)
Changed cpu_thread_to_core() to cpu_core_index_of_thread(int cpu)
The goal is to make 'threads_per_core' accessible to the
pseries_energy module. Instead of making an API to read
threads_per_core, this is a higher level wrapper function to
convert from logical cpu number to core number.
The current APIs cpu_first_thread_in_core() and
cpu_last_thread_in_core() returns logical CPU number while
cpu_thread_to_core() returns core number or index which is
not a logical CPU number. The new APIs are now clearly named to
distinguish 'core number' versus first and last 'logical cpu
number' in that core.
The new APIs cpu_{first,last}_thread_sibling() work on
logical cpu numbers. While cpu_first_thread_of_core() and
cpu_core_index_of_thread() work on core index.
Example usage: (4 threads per core system)
cpu_first_thread_sibling(5) = 4
cpu_last_thread_sibling(5) = 7
cpu_core_index_of_thread(5) = 1
cpu_first_thread_of_core(1) = 4
cpu_core_index_of_thread() is used in cpu_to_drc_index() in the
module and cpu_first_thread_of_core() is used in
drc_index_to_cpu() in the module.
Make API changes to few callers. Export symbols for use in modules.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
90 lines
2.2 KiB
C
90 lines
2.2 KiB
C
#ifndef _ASM_POWERPC_CPUTHREADS_H
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#define _ASM_POWERPC_CPUTHREADS_H
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#include <linux/cpumask.h>
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/*
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* Mapping of threads to cores
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*
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* Note: This implementation is limited to a power of 2 number of
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* threads per core and the same number for each core in the system
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* (though it would work if some processors had less threads as long
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* as the CPU numbers are still allocated, just not brought offline).
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*
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* However, the API allows for a different implementation in the future
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* if needed, as long as you only use the functions and not the variables
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* directly.
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*/
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#ifdef CONFIG_SMP
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extern int threads_per_core;
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extern int threads_shift;
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extern cpumask_t threads_core_mask;
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#else
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#define threads_per_core 1
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#define threads_shift 0
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#define threads_core_mask (CPU_MASK_CPU0)
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#endif
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/* cpu_thread_mask_to_cores - Return a cpumask of one per cores
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* hit by the argument
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*
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* @threads: a cpumask of threads
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*
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* This function returns a cpumask which will have one "cpu" (or thread)
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* bit set for each core that has at least one thread set in the argument.
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*
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* This can typically be used for things like IPI for tlb invalidations
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* since those need to be done only once per core/TLB
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*/
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static inline cpumask_t cpu_thread_mask_to_cores(cpumask_t threads)
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{
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cpumask_t tmp, res;
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int i;
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res = CPU_MASK_NONE;
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for (i = 0; i < NR_CPUS; i += threads_per_core) {
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cpus_shift_left(tmp, threads_core_mask, i);
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if (cpus_intersects(threads, tmp))
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cpu_set(i, res);
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}
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return res;
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}
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static inline int cpu_nr_cores(void)
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{
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return NR_CPUS >> threads_shift;
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}
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static inline cpumask_t cpu_online_cores_map(void)
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{
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return cpu_thread_mask_to_cores(cpu_online_map);
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}
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#ifdef CONFIG_SMP
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int cpu_core_index_of_thread(int cpu);
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int cpu_first_thread_of_core(int core);
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#else
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static inline int cpu_core_index_of_thread(int cpu) { return cpu; }
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static inline int cpu_first_thread_of_core(int core) { return core; }
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#endif
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static inline int cpu_thread_in_core(int cpu)
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{
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return cpu & (threads_per_core - 1);
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}
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static inline int cpu_first_thread_sibling(int cpu)
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{
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return cpu & ~(threads_per_core - 1);
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}
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static inline int cpu_last_thread_sibling(int cpu)
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{
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return cpu | (threads_per_core - 1);
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}
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#endif /* _ASM_POWERPC_CPUTHREADS_H */
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