diff options
Diffstat (limited to 'include/linux/perf_counter.h')
| -rw-r--r-- | include/linux/perf_counter.h | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index f2b914de3f0..e22ab47a2f4 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -170,22 +170,18 @@ struct perf_counter_mmap_page { * u32 seq; * s64 count; * - * again: - * seq = pc->lock; - * if (unlikely(seq & 1)) { - * cpu_relax(); - * goto again; - * } + * do { + * seq = pc->lock; * - * if (pc->index) { - * count = pmc_read(pc->index - 1); - * count += pc->offset; - * } else - * goto regular_read; + * barrier() + * if (pc->index) { + * count = pmc_read(pc->index - 1); + * count += pc->offset; + * } else + * goto regular_read; * - * barrier(); - * if (pc->lock != seq) - * goto again; + * barrier(); + * } while (pc->lock != seq); * * NOTE: for obvious reason this only works on self-monitoring * processes. |