projects / lttng-ust.git / blame
| Commit | Line | Data |
|---|---|---|
| a6352fd4 MD |
1 | #ifndef _LIBRINGBUFFER_SMP_H |
| 2 | #define _LIBRINGBUFFER_SMP_H | |
| 3 | ||
| 4 | /* | |
| 5 | * libringbuffer/smp.h | |
| 6 | * | |
| 7 | * Copyright 2011 (c) - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
| 8 | * | |
| 9 | * Dual LGPL v2.1/GPL v2 license. | |
| 10 | */ | |
| 11 | ||
| 12 | #include <ust/core.h> | |
| 13 | ||
| 14 | /* | |
| 15 | * 4kB of per-cpu data available. Enough to hold the control structures, | |
| 16 | * but not ring buffers. | |
| 17 | */ | |
| 18 | #define PER_CPU_MEM_SIZE 4096 | |
| 19 | ||
| 20 | extern int __num_possible_cpus; | |
| 21 | extern void _get_num_possible_cpus(void); | |
| 22 | ||
| 23 | static inline | |
| 24 | int num_possible_cpus(void) | |
| 25 | { | |
| 26 | if (!__num_possible_cpus) | |
| 27 | _get_num_possible_cpus(); | |
| 28 | return __num_possible_cpus; | |
| 29 | } | |
| 30 | ||
| 31 | /* | |
| 32 | * get_cpu() returns the current CPU number. It may change due to | |
| 33 | * migration, so it is only statistically accurate. | |
| 34 | */ | |
| 35 | #ifndef UST_VALGRIND | |
| 36 | static inline | |
| 37 | int get_cpu(void) | |
| 38 | { | |
| 39 | int cpu; | |
| 40 | ||
| 41 | cpu = sched_getcpu(); | |
| 42 | if (likely(cpu >= 0)) | |
| 43 | return cpu; | |
| 44 | /* | |
| 45 | * If getcpu(2) is not implemented in the Kernel use CPU 0 as fallback. | |
| 46 | */ | |
| 47 | return 0; | |
| 48 | } | |
| 49 | ||
| 50 | #else /* #else #ifndef UST_VALGRIND */ | |
| 51 | static inline | |
| 52 | int get_cpu(void) | |
| 53 | { | |
| 54 | /* | |
| 55 | * Valgrind does not support the sched_getcpu() vsyscall. | |
| 56 | * It causes it to detect a segfault in the program and stop it. | |
| 57 | * So if we want to check libust with valgrind, we have to refrain | |
| 58 | * from using this call. TODO: it would probably be better to return | |
| 59 | * other values too, to better test it. | |
| 60 | */ | |
| 61 | return 0; | |
| 62 | } | |
| 63 | #endif /* #else #ifndef UST_VALGRIND */ | |
| 64 | ||
| 65 | static inline | |
| 66 | void put_cpu(void) | |
| 67 | { | |
| 68 | } | |
| 69 | ||
| 70 | #define for_each_possible_cpu(cpu) \ | |
| 71 | for ((cpu) = 0; (cpu) < num_possible_cpus(); (cpu)++) | |
| 72 | ||
| 73 | #endif /* _LIBRINGBUFFER_SMP_H */ |