2019-10-07 12:55:07

by Jiri Olsa

[permalink] [raw]
Subject: [PATCH 11/36] libperf: Add perf_mmap__read_done() function

Move perf_mmap__read_init() from tools/perf to libperf and export it in
the perf/mmap.h header.

Signed-off-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/arch/x86/tests/perf-time-to-tsc.c | 2 +-
tools/perf/builtin-kvm.c | 2 +-
tools/perf/builtin-top.c | 2 +-
tools/perf/builtin-trace.c | 2 +-
tools/perf/lib/include/perf/mmap.h | 1 +
tools/perf/lib/libperf.map | 1 +
tools/perf/lib/mmap.c | 17 +++++++++++++++++
tools/perf/tests/backward-ring-buffer.c | 2 +-
tools/perf/tests/bpf.c | 2 +-
tools/perf/tests/code-reading.c | 2 +-
tools/perf/tests/keep-tracking.c | 2 +-
tools/perf/tests/mmap-basic.c | 2 +-
tools/perf/tests/openat-syscall-tp-fields.c | 2 +-
tools/perf/tests/perf-record.c | 2 +-
tools/perf/tests/sw-clock.c | 2 +-
tools/perf/tests/switch-tracking.c | 2 +-
tools/perf/tests/task-exit.c | 2 +-
tools/perf/util/evlist.c | 2 +-
tools/perf/util/mmap.c | 17 -----------------
tools/perf/util/mmap.h | 1 -
20 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/tools/perf/arch/x86/tests/perf-time-to-tsc.c b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
index 6a0c3ff78e01..c90d925f7ae6 100644
--- a/tools/perf/arch/x86/tests/perf-time-to-tsc.c
+++ b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
@@ -142,7 +142,7 @@ int test__perf_time_to_tsc(struct test *test __maybe_unused, int subtest __maybe
next_event:
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (!comm1_time || !comm2_time)
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index b6a8078dd446..4c087a8c9fed 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -794,7 +794,7 @@ static s64 perf_kvm__mmap_read_idx(struct perf_kvm_stat *kvm, int idx,
break;
}

- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
return n;
}

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 4a4bb7b20c39..1a54069ccd9c 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -894,7 +894,7 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
}
}

- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

static void perf_top__mmap_read(struct perf_top *top)
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 49a0799ccf81..5fc3051a0938 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3471,7 +3471,7 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
draining = true;
}
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (trace->nr_events == before) {
diff --git a/tools/perf/lib/include/perf/mmap.h b/tools/perf/lib/include/perf/mmap.h
index 646e9052b003..4f946e7f724b 100644
--- a/tools/perf/lib/include/perf/mmap.h
+++ b/tools/perf/lib/include/perf/mmap.h
@@ -8,5 +8,6 @@ struct perf_mmap;

LIBPERF_API void perf_mmap__consume(struct perf_mmap *map);
LIBPERF_API int perf_mmap__read_init(struct perf_mmap *map);
+LIBPERF_API void perf_mmap__read_done(struct perf_mmap *map);

#endif /* __LIBPERF_MMAP_H */
diff --git a/tools/perf/lib/libperf.map b/tools/perf/lib/libperf.map
index bc3fbb213a3e..7e3ea2e9c917 100644
--- a/tools/perf/lib/libperf.map
+++ b/tools/perf/lib/libperf.map
@@ -42,6 +42,7 @@ LIBPERF_0.0.1 {
perf_evlist__poll;
perf_mmap__consume;
perf_mmap__read_init;
+ perf_mmap__read_done;
local:
*;
};
diff --git a/tools/perf/lib/mmap.c b/tools/perf/lib/mmap.c
index 0e78c365ed90..7d39289a4a22 100644
--- a/tools/perf/lib/mmap.c
+++ b/tools/perf/lib/mmap.c
@@ -174,3 +174,20 @@ int perf_mmap__read_init(struct perf_mmap *map)

return __perf_mmap__read_init(map);
}
+
+/*
+ * Mandatory for overwrite mode
+ * The direction of overwrite mode is backward.
+ * The last perf_mmap__read() will set tail to map->core.prev.
+ * Need to correct the map->core.prev to head which is the end of next read.
+ */
+void perf_mmap__read_done(struct perf_mmap *map)
+{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return;
+
+ map->prev = perf_mmap__read_head(map);
+}
diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index ff3a986983ab..13e67cd213bd 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -54,7 +54,7 @@ static int count_samples(struct evlist *evlist, int *sample_count,
return TEST_FAIL;
}
}
- perf_mmap__read_done(map);
+ perf_mmap__read_done(&map->core);
}
return TEST_OK;
}
diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index 73d26c63d624..fd45529e29c1 100644
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -194,7 +194,7 @@ static int do_test(struct bpf_object *obj, int (*func)(void),
if (type == PERF_RECORD_SAMPLE)
count ++;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (count != expect) {
diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index cf992e0b27ff..9947cda29bad 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -435,7 +435,7 @@ static int process_events(struct machine *machine, struct evlist *evlist,
if (ret < 0)
return ret;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}
return 0;
}
diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
index e85da7e77269..e950907f6f57 100644
--- a/tools/perf/tests/keep-tracking.c
+++ b/tools/perf/tests/keep-tracking.c
@@ -49,7 +49,7 @@ static int find_comm(struct evlist *evlist, const char *comm)
found += 1;
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}
return found;
}
diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 77f42f0ac15d..bb15d405a42c 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -142,7 +142,7 @@ int test__basic_mmap(struct test *test __maybe_unused, int subtest __maybe_unuse
nr_events[evsel->idx]++;
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
err = 0;
diff --git a/tools/perf/tests/openat-syscall-tp-fields.c b/tools/perf/tests/openat-syscall-tp-fields.c
index d6a563120d93..c95eb1bbf396 100644
--- a/tools/perf/tests/openat-syscall-tp-fields.c
+++ b/tools/perf/tests/openat-syscall-tp-fields.c
@@ -124,7 +124,7 @@ int test__syscall_openat_tp_fields(struct test *test __maybe_unused, int subtest

goto out_ok;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (nr_events == before)
diff --git a/tools/perf/tests/perf-record.c b/tools/perf/tests/perf-record.c
index 2587cb8b2c0f..92a53be3b32b 100644
--- a/tools/perf/tests/perf-record.c
+++ b/tools/perf/tests/perf-record.c
@@ -279,7 +279,7 @@ int test__PERF_RECORD(struct test *test __maybe_unused, int subtest __maybe_unus

perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

/*
diff --git a/tools/perf/tests/sw-clock.c b/tools/perf/tests/sw-clock.c
index 808669507c30..ace20921ad55 100644
--- a/tools/perf/tests/sw-clock.c
+++ b/tools/perf/tests/sw-clock.c
@@ -120,7 +120,7 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
next_event:
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
if ((u64) nr_samples == total_periods) {
diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
index bedfdec34972..8400fb17c170 100644
--- a/tools/perf/tests/switch-tracking.c
+++ b/tools/perf/tests/switch-tracking.c
@@ -280,7 +280,7 @@ static int process_events(struct evlist *evlist,
if (ret < 0)
goto out_free_nodes;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

events_array = calloc(cnt, sizeof(struct event_node));
diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c
index 035d42375d4b..c6a13948821c 100644
--- a/tools/perf/tests/task-exit.c
+++ b/tools/perf/tests/task-exit.c
@@ -127,7 +127,7 @@ int test__task_exit(struct test *test __maybe_unused, int subtest __maybe_unused

perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
if (!exited || !nr_exit) {
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 67fe34672224..830dc91994bc 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1753,7 +1753,7 @@ static void *perf_evlist__poll_thread(void *arg)
perf_mmap__consume(&map->core);
got_data = true;
}
- perf_mmap__read_done(map);
+ perf_mmap__read_done(&map->core);
}

if (draining && !got_data)
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 59379118c2f1..2dedef9b06fd 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -405,20 +405,3 @@ int perf_mmap__push(struct mmap *md, void *to,
out:
return rc;
}
-
-/*
- * Mandatory for overwrite mode
- * The direction of overwrite mode is backward.
- * The last perf_mmap__read() will set tail to map->core.prev.
- * Need to correct the map->core.prev to head which is the end of next read.
- */
-void perf_mmap__read_done(struct mmap *map)
-{
- /*
- * Check if event was unmapped due to a POLLHUP/POLLERR.
- */
- if (!refcount_read(&map->core.refcnt))
- return;
-
- map->core.prev = perf_mmap__read_head(&map->core);
-}
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index 6d818ef51f05..0b15702be1a5 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -54,5 +54,4 @@ int perf_mmap__push(struct mmap *md, void *to,

size_t mmap__mmap_len(struct mmap *map);

-void perf_mmap__read_done(struct mmap *map);
#endif /*__PERF_MMAP_H */
--
2.21.0


Subject: [tip: perf/core] libperf: Adopt perf_mmap__read_done() from tools/perf

The following commit has been merged into the perf/core branch of tip:

Commit-ID: 32fdc2ca7e2ae8ae5d0ff660ca7783acd8ee6396
Gitweb: https://git.kernel.org/tip/32fdc2ca7e2ae8ae5d0ff660ca7783acd8ee6396
Author: Jiri Olsa <[email protected]>
AuthorDate: Mon, 07 Oct 2019 14:53:19 +02:00
Committer: Arnaldo Carvalho de Melo <[email protected]>
CommitterDate: Thu, 10 Oct 2019 11:45:32 -03:00

libperf: Adopt perf_mmap__read_done() from tools/perf

Move perf_mmap__read_init() from tools/perf to libperf and export it in
the perf/mmap.h header.

Signed-off-by: Jiri Olsa <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Michael Petlan <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
---
tools/perf/arch/x86/tests/perf-time-to-tsc.c | 2 +-
tools/perf/builtin-kvm.c | 2 +-
tools/perf/builtin-top.c | 2 +-
tools/perf/builtin-trace.c | 2 +-
tools/perf/lib/include/perf/mmap.h | 1 +
tools/perf/lib/libperf.map | 1 +
tools/perf/lib/mmap.c | 17 +++++++++++++++++
tools/perf/tests/backward-ring-buffer.c | 2 +-
tools/perf/tests/bpf.c | 2 +-
tools/perf/tests/code-reading.c | 2 +-
tools/perf/tests/keep-tracking.c | 2 +-
tools/perf/tests/mmap-basic.c | 2 +-
tools/perf/tests/openat-syscall-tp-fields.c | 2 +-
tools/perf/tests/perf-record.c | 2 +-
tools/perf/tests/sw-clock.c | 2 +-
tools/perf/tests/switch-tracking.c | 2 +-
tools/perf/tests/task-exit.c | 2 +-
tools/perf/util/evlist.c | 2 +-
tools/perf/util/mmap.c | 17 -----------------
tools/perf/util/mmap.h | 1 -
20 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/tools/perf/arch/x86/tests/perf-time-to-tsc.c b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
index 6a0c3ff..c90d925 100644
--- a/tools/perf/arch/x86/tests/perf-time-to-tsc.c
+++ b/tools/perf/arch/x86/tests/perf-time-to-tsc.c
@@ -142,7 +142,7 @@ int test__perf_time_to_tsc(struct test *test __maybe_unused, int subtest __maybe
next_event:
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (!comm1_time || !comm2_time)
diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index b6a8078..4c087a8 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -794,7 +794,7 @@ static s64 perf_kvm__mmap_read_idx(struct perf_kvm_stat *kvm, int idx,
break;
}

- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
return n;
}

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 4a4bb7b..1a54069 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -894,7 +894,7 @@ static void perf_top__mmap_read_idx(struct perf_top *top, int idx)
}
}

- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

static void perf_top__mmap_read(struct perf_top *top)
diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index cd69d68..2311628 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -3821,7 +3821,7 @@ again:
draining = true;
}
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (trace->nr_events == before) {
diff --git a/tools/perf/lib/include/perf/mmap.h b/tools/perf/lib/include/perf/mmap.h
index 646e905..4f946e7 100644
--- a/tools/perf/lib/include/perf/mmap.h
+++ b/tools/perf/lib/include/perf/mmap.h
@@ -8,5 +8,6 @@ struct perf_mmap;

LIBPERF_API void perf_mmap__consume(struct perf_mmap *map);
LIBPERF_API int perf_mmap__read_init(struct perf_mmap *map);
+LIBPERF_API void perf_mmap__read_done(struct perf_mmap *map);

#endif /* __LIBPERF_MMAP_H */
diff --git a/tools/perf/lib/libperf.map b/tools/perf/lib/libperf.map
index bc3fbb2..7e3ea2e 100644
--- a/tools/perf/lib/libperf.map
+++ b/tools/perf/lib/libperf.map
@@ -42,6 +42,7 @@ LIBPERF_0.0.1 {
perf_evlist__poll;
perf_mmap__consume;
perf_mmap__read_init;
+ perf_mmap__read_done;
local:
*;
};
diff --git a/tools/perf/lib/mmap.c b/tools/perf/lib/mmap.c
index fdbc6c5..97297cb 100644
--- a/tools/perf/lib/mmap.c
+++ b/tools/perf/lib/mmap.c
@@ -175,3 +175,20 @@ int perf_mmap__read_init(struct perf_mmap *map)

return __perf_mmap__read_init(map);
}
+
+/*
+ * Mandatory for overwrite mode
+ * The direction of overwrite mode is backward.
+ * The last perf_mmap__read() will set tail to map->core.prev.
+ * Need to correct the map->core.prev to head which is the end of next read.
+ */
+void perf_mmap__read_done(struct perf_mmap *map)
+{
+ /*
+ * Check if event was unmapped due to a POLLHUP/POLLERR.
+ */
+ if (!refcount_read(&map->refcnt))
+ return;
+
+ map->prev = perf_mmap__read_head(map);
+}
diff --git a/tools/perf/tests/backward-ring-buffer.c b/tools/perf/tests/backward-ring-buffer.c
index ff3a986..13e67cd 100644
--- a/tools/perf/tests/backward-ring-buffer.c
+++ b/tools/perf/tests/backward-ring-buffer.c
@@ -54,7 +54,7 @@ static int count_samples(struct evlist *evlist, int *sample_count,
return TEST_FAIL;
}
}
- perf_mmap__read_done(map);
+ perf_mmap__read_done(&map->core);
}
return TEST_OK;
}
diff --git a/tools/perf/tests/bpf.c b/tools/perf/tests/bpf.c
index 73d26c6..fd45529 100644
--- a/tools/perf/tests/bpf.c
+++ b/tools/perf/tests/bpf.c
@@ -194,7 +194,7 @@ static int do_test(struct bpf_object *obj, int (*func)(void),
if (type == PERF_RECORD_SAMPLE)
count ++;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (count != expect) {
diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index cf992e0..9947cda 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -435,7 +435,7 @@ static int process_events(struct machine *machine, struct evlist *evlist,
if (ret < 0)
return ret;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}
return 0;
}
diff --git a/tools/perf/tests/keep-tracking.c b/tools/perf/tests/keep-tracking.c
index e85da7e..e950907 100644
--- a/tools/perf/tests/keep-tracking.c
+++ b/tools/perf/tests/keep-tracking.c
@@ -49,7 +49,7 @@ static int find_comm(struct evlist *evlist, const char *comm)
found += 1;
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}
return found;
}
diff --git a/tools/perf/tests/mmap-basic.c b/tools/perf/tests/mmap-basic.c
index 77f42f0..bb15d40 100644
--- a/tools/perf/tests/mmap-basic.c
+++ b/tools/perf/tests/mmap-basic.c
@@ -142,7 +142,7 @@ int test__basic_mmap(struct test *test __maybe_unused, int subtest __maybe_unuse
nr_events[evsel->idx]++;
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
err = 0;
diff --git a/tools/perf/tests/openat-syscall-tp-fields.c b/tools/perf/tests/openat-syscall-tp-fields.c
index d6a5631..c95eb1b 100644
--- a/tools/perf/tests/openat-syscall-tp-fields.c
+++ b/tools/perf/tests/openat-syscall-tp-fields.c
@@ -124,7 +124,7 @@ int test__syscall_openat_tp_fields(struct test *test __maybe_unused, int subtest

goto out_ok;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

if (nr_events == before)
diff --git a/tools/perf/tests/perf-record.c b/tools/perf/tests/perf-record.c
index 2587cb8..92a53be 100644
--- a/tools/perf/tests/perf-record.c
+++ b/tools/perf/tests/perf-record.c
@@ -279,7 +279,7 @@ int test__PERF_RECORD(struct test *test __maybe_unused, int subtest __maybe_unus

perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

/*
diff --git a/tools/perf/tests/sw-clock.c b/tools/perf/tests/sw-clock.c
index 8086695..ace2092 100644
--- a/tools/perf/tests/sw-clock.c
+++ b/tools/perf/tests/sw-clock.c
@@ -120,7 +120,7 @@ static int __test__sw_clock_freq(enum perf_sw_ids clock_id)
next_event:
perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
if ((u64) nr_samples == total_periods) {
diff --git a/tools/perf/tests/switch-tracking.c b/tools/perf/tests/switch-tracking.c
index bedfdec..8400fb1 100644
--- a/tools/perf/tests/switch-tracking.c
+++ b/tools/perf/tests/switch-tracking.c
@@ -280,7 +280,7 @@ static int process_events(struct evlist *evlist,
if (ret < 0)
goto out_free_nodes;
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);
}

events_array = calloc(cnt, sizeof(struct event_node));
diff --git a/tools/perf/tests/task-exit.c b/tools/perf/tests/task-exit.c
index 035d423..c6a1394 100644
--- a/tools/perf/tests/task-exit.c
+++ b/tools/perf/tests/task-exit.c
@@ -127,7 +127,7 @@ retry:

perf_mmap__consume(&md->core);
}
- perf_mmap__read_done(md);
+ perf_mmap__read_done(&md->core);

out_init:
if (!exited || !nr_exit) {
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index d9a4a4b..6e070ee 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1822,7 +1822,7 @@ static void *perf_evlist__poll_thread(void *arg)
perf_mmap__consume(&map->core);
got_data = true;
}
- perf_mmap__read_done(map);
+ perf_mmap__read_done(&map->core);
}

if (draining && !got_data)
diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 5937911..2dedef9 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -405,20 +405,3 @@ int perf_mmap__push(struct mmap *md, void *to,
out:
return rc;
}
-
-/*
- * Mandatory for overwrite mode
- * The direction of overwrite mode is backward.
- * The last perf_mmap__read() will set tail to map->core.prev.
- * Need to correct the map->core.prev to head which is the end of next read.
- */
-void perf_mmap__read_done(struct mmap *map)
-{
- /*
- * Check if event was unmapped due to a POLLHUP/POLLERR.
- */
- if (!refcount_read(&map->core.refcnt))
- return;
-
- map->core.prev = perf_mmap__read_head(&map->core);
-}
diff --git a/tools/perf/util/mmap.h b/tools/perf/util/mmap.h
index 6d818ef..0b15702 100644
--- a/tools/perf/util/mmap.h
+++ b/tools/perf/util/mmap.h
@@ -54,5 +54,4 @@ int perf_mmap__push(struct mmap *md, void *to,

size_t mmap__mmap_len(struct mmap *map);

-void perf_mmap__read_done(struct mmap *map);
#endif /*__PERF_MMAP_H */