On 07/14/2014 11:18 PM, Arnaldo Carvalho de Melo wrote:
> Em Mon, Jul 14, 2014 at 01:02:26PM +0300, Adrian Hunter escreveu:
>> Events like sched_switch do not provide a pid (tgid)
>> which can result in threads with an unknown pid. If
>> the pid is later discovered, join the map groups.
>> Note the thread's map groups should be empty because
>> they are populated by MMAP events which do provide the
>> pid and tid.
>>
>> Signed-off-by: Adrian Hunter <adrian.hun...@intel.com>
>> ---
>> tools/perf/util/machine.c | 22 ++++++++++++++++------
>> tools/perf/util/map.c | 14 ++++++++++++++
>> tools/perf/util/map.h | 1 +
>> tools/perf/util/thread.c | 35 +++++++++++++++++++++++++++++++++++
>> tools/perf/util/thread.h | 1 +
>> 5 files changed, 67 insertions(+), 6 deletions(-)
>>
>> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
>> index 5b80877..0fa93c1 100644
>> --- a/tools/perf/util/machine.c
>> +++ b/tools/perf/util/machine.c
>> @@ -272,6 +272,17 @@ void machines__set_id_hdr_size(struct machines
>> *machines, u16 id_hdr_size)
>> return;
>> }
>>
>> +static void machine__update_thread_pid(struct machine *machine,
>> + struct thread *th, pid_t pid)
>> +{
>> + if (pid != th->pid_ && pid != -1 && th->pid_ == -1) {
>> + th->pid_ = pid;
>> + if (thread__join_map_groups(th, machine))
>> + pr_err("Failed to join map groups for %d:%d\n",
>> + th->pid_, th->tid);
>> + }
>> +}
>> +
>
> I think you should combine the above function with
> thread__join_map_groups, and I think that the method belongs to the
> 'machine' class, see below for further comments on this...
>
>> diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
>> index 7a32f44..ca94295 100644
>> --- a/tools/perf/util/thread.c
>> +++ b/tools/perf/util/thread.c
>> @@ -24,6 +24,41 @@ int thread__init_map_groups(struct thread *thread, struct
>> machine *machine)
>> return thread->mg ? 0 : -1;
>> }
>>
>> +int thread__join_map_groups(struct thread *thread, struct machine *machine)
>> +{
>> + struct thread *leader;
>> + pid_t pid = thread->pid_;
>> +
>> + if (pid == thread->tid)
>> + return 0;
>> +
>> + leader = machine__findnew_thread(machine, pid, pid);
>> + if (!leader)
>> + return -ENOMEM;
>> +
>> + if (!leader->mg)
>> + leader->mg = map_groups__new();
>> +
>> + if (!leader->mg)
>> + return -ENOMEM;
>> +
>> + if (thread->mg) {
>> + /*
>> + * Maps are created from MMAP events which provide the pid and
>> + * tid. Consequently there never should be any maps on a thread
>> + * with an unknown pid. Just print an error if there are.
>> + */
>> + if (!map_groups__empty(thread->mg))
>> + pr_err("Discarding thread maps for %d:%d\n",
>> + thread->pid_, thread->tid);
>
> Because there is nothing in this function (thread__join_map_groups),
> checking if it is operating on a thread that has an unknown pid.
>
> So, please consider merging this and its sole caller,
> machine__update_thread_pid, so that the test is in the same function as
> the assumption that it is operating on a thread with an unknown pid.
You have it in your tree now. Do you want another patch
to do that?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
