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e602ffb2fa
Currently, cpu_online_cores_map returns a mask, which for every core with at least one online thread, has the bit for thread 0 of the core set to 1, and the bits for all other threads of the core set to 0. But thread 0 of the core itself may not be online always. In such cases, if the returned mask is used for IPI, then it'll cause IPIs to be skipped on cores where the first thread is offline, because the IPI code refuses to send IPIs to offline threads. Fix this by setting the bit of the first online thread in the core. This is done by fixing this in the underlying function cpu_thread_mask_to_cores. The result has the property that for all cores with online threads, there is one bit set in the returned map. And further, all bits that are set in the returned map correspond to online threads. Signed-off-by: Shreyas B. Prabhu <shreyas@linux.vnet.ibm.com> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> [ Changelog from Michael Ellerman <mpe@ellerman.id.au> ] Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
101 lines
2.5 KiB
C
101 lines
2.5 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 online).
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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_per_subcore;
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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_per_subcore 1
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#define threads_shift 0
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#define threads_core_mask (*get_cpu_mask(0))
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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 online threads
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*
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* This function returns a cpumask which will have one online cpu's
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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(const struct cpumask *threads)
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{
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cpumask_t tmp, res;
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int i, cpu;
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cpumask_clear(&res);
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for (i = 0; i < NR_CPUS; i += threads_per_core) {
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cpumask_shift_left(&tmp, &threads_core_mask, i);
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if (cpumask_intersects(threads, &tmp)) {
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cpu = cpumask_next_and(-1, &tmp, cpu_online_mask);
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if (cpu < nr_cpu_ids)
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cpumask_set_cpu(cpu, &res);
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}
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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_cpu_ids >> 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_mask);
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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_thread_in_subcore(int cpu)
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{
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return cpu & (threads_per_subcore - 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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