Re: [PATCH v5 4/8] perf record: Introduce rec->overwrite_evlist for overwritable events

["Wangnan (F)" <wangnan0@huawei.com>]

On 2016/5/25 13:03, Wang Nan wrote:
> Create an auxiliary evlist for overwritable events.
>
> Before mmap, build this evlist and set 'overwrite' and 'backward'
> attribute. Since perf_evlist__mmap_ex() only maps events when
> evsel->overwrite matches evlist's corresponding attributes, with
> these two evlists an event goes to either rec->evlist or
> rec->overwrite_evlist.
>
> Signed-off-by: Wang Nan <wangnan0@huawei.com>
> Cc: He Kuang <hekuang@huawei.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Zefan Li <lizefan@huawei.com>
> Cc: pi3orama@163.com
> ---
>   tools/perf/builtin-record.c | 138 ++++++++++++++++++++++++++++++++++++--------
>   1 file changed, 114 insertions(+), 24 deletions(-)
>

[SNIP]

> @@ -941,7 +1026,10 @@ static int __cmd_record(struct record *rec, int argc, const char **argv)
>   				err = 0;
>   			waking++;
>   
> -			if (perf_evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP) == 0)
> +			active_evts = perf_evlist__filter_pollfd(rec->evlist, POLLERR | POLLHUP);
> +			active_evts += perf_evlist__filter_pollfd(rec->overwrite_evlist, POLLERR | POLLHUP);

Sorry, before calling filter here should check if rec->overwrite_evlist 
is not NULL.
I'll resend this patch with this problem fixed soon.