linux-kernel - [PATCH V3 01/25] perf tools: Amend mmap ref counting for the AUX area mmap

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Message-Id: <1429903807-20559-2-git-send-email-adrian.hunter@intel.com>
Date:	Fri, 24 Apr 2015 22:29:43 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	linux-kernel@...r.kernel.org, David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Jiri Olsa <jolsa@...hat.com>,
	Namhyung Kim <namhyung@...il.com>,
	Stephane Eranian <eranian@...gle.com>
Subject: [PATCH V3 01/25] perf tools: Amend mmap ref counting for the AUX area mmap

Reference counting of the mmap buffer does not work
correctly when there is an AUX area mmap also.

In snapshot mode it is not easy to know if the AUX area
mmap buffer contains usefull information. Equally the
evlist does not know if the recording is in sanpshot
mode anyway.

Consequently, for now just assume the AUX area mmap
always has data, which will just cause the mmap buffer
to remain mmapped for the duration of the recording.

Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
---
 tools/perf/util/evlist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 0ec8c3b..7ec1bf9 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -695,7 +695,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
 
 static bool perf_mmap__empty(struct perf_mmap *md)
 {
-	return perf_mmap__read_head(md) == md->prev;
+	return perf_mmap__read_head(md) == md->prev && !md->auxtrace_mmap.base;
 }
 
 static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
-- 
1.9.1

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