PERF_MAX_CONTEXTS_PER_STACK   23 kernel/events/callchain.c int sysctl_perf_event_max_contexts_per_stack __read_mostly = PERF_MAX_CONTEXTS_PER_STACK;
PERF_MAX_CONTEXTS_PER_STACK   43 tools/perf/util/util.c int sysctl_perf_event_max_contexts_per_stack = PERF_MAX_CONTEXTS_PER_STACK;