libringbuffer/smp.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #ifndef _LIBRINGBUFFER_SMP_H
   8 #define _LIBRINGBUFFER_SMP_H
   9
  10 #include "ust-helper.h"
  11 #include "getcpu.h"
  12
  13 /*
  14  * 4kB of per-cpu data available. Enough to hold the control structures,
  15  * but not ring buffers.
  16  */
  17 #define PER_CPU_MEM_SIZE        4096
  18
  19 LTTNG_HIDDEN
  20 extern int __num_possible_cpus;
  21 LTTNG_HIDDEN
  22 extern void _get_num_possible_cpus(void);
  23
  24 static inline
  25 int num_possible_cpus(void)
  26 {
  27         if (!__num_possible_cpus)
  28                 _get_num_possible_cpus();
  29         return __num_possible_cpus;
  30 }
  31
  32 #define for_each_possible_cpu(cpu)              \
  33         for ((cpu) = 0; (cpu) < num_possible_cpus(); (cpu)++)
  34
  35 #endif /* _LIBRINGBUFFER_SMP_H */