Re: [PATCH 17/25] perf callchain: Allow for max_stack greater than PERF_MAX_STACK_DEPTH

From: Adrian Hunter
Date: Tue Sep 29 2015 - 04:19:23 EST


On 28/09/15 23:08, Arnaldo Carvalho de Melo wrote:
> Em Fri, Sep 25, 2015 at 04:15:48PM +0300, Adrian Hunter escreveu:
>> Adjust the validation to allow for max_stack greater than
>> PERF_MAX_STACK_DEPTH.
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>> ---
>> tools/perf/util/machine.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
>> index fd1efeafb343..d7bd9a304535 100644
>> --- a/tools/perf/util/machine.c
>> +++ b/tools/perf/util/machine.c
>> @@ -1831,7 +1831,7 @@ static int thread__resolve_callchain_sample(struct thread *thread,
>> }
>>
>> check_calls:
>> - if (chain->nr > PERF_MAX_STACK_DEPTH) {
>> + if (chain->nr > PERF_MAX_STACK_DEPTH && (int)chain->nr > max_stack) {
>
> Both?

Yes.

In the case of a hardware generated callchain, the callchain can be up to
PERF_MAX_STACK_DEPTH but max_stack can be less than PERF_MAX_STACK_DEPTH to
limit the number processed.

In the case of a synthesized callchain, the callchain can be up to max_stack
which might be more than PERF_MAX_STACK_DEPTH.

>
>> pr_warning("corrupted callchain. skipping...\n");
>> return 0;
>> }
>> --
>> 1.9.1
>

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