• Arnaldo Carvalho de Melo's avatar
    perf core: Add a 'nr' field to perf_event_callchain_context · 3b1fff08
    Arnaldo Carvalho de Melo authored
    We will use it to count how many addresses are in the entry->ip[] array,
    excluding PERF_CONTEXT_{KERNEL,USER,etc} entries, so that we can really
    return the number of entries specified by the user via the relevant
    sysctl, kernel.perf_event_max_contexts, or via the per event
    perf_event_attr.sample_max_stack knob.
    
    This way we keep the perf_sample->ip_callchain->nr meaning, that is the
    number of entries, be it real addresses or PERF_CONTEXT_ entries, while
    honouring the max_stack knobs, i.e. the end result will be max_stack
    entries if we have at least that many entries in a given stack trace.
    
    Cc: David Ahern <dsahern@gmail.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Namhyung Kim <namhyung@kernel.org>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Link: http://lkml.kernel.org/n/tip-s8teto51tdqvlfhefndtat9r@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    3b1fff08
perf_event.c 1.81 KB