[PATCH] perf top: Fix annoying fallback message on older kernel

[kan.liang@intel.com]

From: Kan Liang <Kan.liang@intel.com>

On older (v4.4) kernels, the annoying fallback message can be observed
in 'perf top'.

The 'perf top' has been changed to overwrite mode since
'commit ebebbf082357 ("perf top: Switch default mode to overwrite mode")'
For the older kernels which don't have overwrite mode support, the 'perf
top' will fall back to non-overwrite mode and print out the fallback
message by ui__warning, which needs user's input to close.

The fallback message is not critical message for end users. Turning it
to debug message which is printed when running with -vv.

Fixes: ebebbf082357 ("perf top: Switch default mode to overwrite mode")
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Kan Liang <Kan.liang@intel.com>
---
 tools/perf/builtin-top.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b7c823b..35ac016 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -991,7 +991,7 @@ static int perf_top_overwrite_fallback(struct perf_top *top,
 	evlist__for_each_entry(evlist, counter)
 		counter->attr.write_backward = false;
 	opts->overwrite = false;
-	ui__warning("fall back to non-overwrite mode\n");
+	pr_debug2("fall back to non-overwrite mode\n");
 	return 1;
 }
 
-- 
2.7.4