diff options
| author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-05-10 18:08:32 -0300 |
|---|---|---|
| committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-05-16 23:11:51 -0300 |
| commit | 3b1fff08038bd0792b1aa1e9703b2dd0512a3fd0 (patch) | |
| tree | 894e513ec904c0b4249917b64adac9d5bda162b5 /include/linux/perf_event.h | |
| parent | cfbcf468454ab4b20f0b4b62da51920b99fdb19e (diff) | |
perf core: Add a 'nr' field to perf_event_callchain_context
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.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index dbd18246b36e..3803bb1a862b 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -64,6 +64,7 @@ struct perf_callchain_entry { struct perf_callchain_entry_ctx { struct perf_callchain_entry *entry; u32 max_stack; + u32 nr; }; struct perf_raw_record { @@ -1080,9 +1081,10 @@ extern int sysctl_perf_event_max_stack; static inline int perf_callchain_store(struct perf_callchain_entry_ctx *ctx, u64 ip) { - struct perf_callchain_entry *entry = ctx->entry; - if (entry->nr < ctx->max_stack) { + if (ctx->nr < ctx->max_stack) { + struct perf_callchain_entry *entry = ctx->entry; entry->ip[entry->nr++] = ip; + ++ctx->nr; return 0; } else { return -1; /* no more room, stop walking the stack */ |