perf record: Fix way of handling non-perf-event pollfds

perf record __cmd_record() does not poll evlist pollfds. Instead it polls
thread_data[0].pollfd. That happens whether or not threads are being used.

perf record duplicates evlist mmap pollfds as needed for separate threads.
The non-perf-event represented by evlist->ctl_fd has to handled separately,
which is done explicitly, duplicating it into the thread_data[0] pollfds.
That approach neglects any other non-perf-event file descriptors. Currently
there is also done_fd which needs the same handling.

Add a new generalized approach.

Add fdarray_flag__non_perf_event to identify the file descriptors that
need the special handling. For those cases, also keep a mapping of the
evlist pollfd index and thread pollfd index, so that the evlist revents
can be updated.

Although this patch adds the new handling, it does not take it into use.
There is no functional change, but it is the precursor to a fix, so is
marked as a fix.

Fixes: 415ccb58f68a6beb ("perf record: Introduce thread specific data array")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220824072814.16422-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 3 insertions, 2 deletions

diff --git a/tools/lib/api/fd/array.h b/tools/lib/api/fd/array.h
index 60ad197c8ee9..5c01f7b05dfb 100644
--- a/tools/lib/api/fd/array.h
+++ b/tools/lib/api/fd/array.h
@@ -31,8 +31,9 @@ struct fdarray {
 };
 
 enum fdarray_flags {
-	fdarray_flag__default	    = 0x00000000,
-	fdarray_flag__nonfilterable = 0x00000001
+	fdarray_flag__default		= 0x00000000,
+	fdarray_flag__nonfilterable	= 0x00000001,
+	fdarray_flag__non_perf_event	= 0x00000002,
 };
 
 void fdarray__init(struct fdarray *fda, int nr_autogrow);