perf trace: Let the perf_evlist__mmap autosize the number of pages to…

… use

So that normal users can run 'trace', we were using a hardcoded 1024
pages value that was more than the default /proc/sys/kernel/perf_event_mlock_kb
setting.

Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Don Zickus <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

tools/perf/builtin-trace.c

@@ -2485,7 +2485,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused)
 			.user_freq     = UINT_MAX,
 			.user_interval = ULLONG_MAX,
 			.no_buffering  = true,
-			.mmap_pages    = 1024,
+			.mmap_pages    = UINT_MAX,
 		},
 		.output = stdout,
 		.show_comm = true,