[tip:perf/core] perf tools: Fix dso__data_read_offset() file opening

From: tip-bot for Namhyung Kim
Date: Wed May 27 2015 - 12:49:05 EST


Commit-ID: 71ff824a60a7b0d9d0746e6e237fe4735077e5b4
Gitweb: http://git.kernel.org/tip/71ff824a60a7b0d9d0746e6e237fe4735077e5b4
Author: Namhyung Kim <namhyung@xxxxxxxxxx>
AuthorDate: Thu, 21 May 2015 01:03:39 +0900
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Wed, 27 May 2015 12:21:44 -0300

perf tools: Fix dso__data_read_offset() file opening

When dso__data_read_offset/addr() is called without prior dso__data_fd()
(or other functions which call it internally), it failed to open dso in
data_file_size() since its binary type was not identified.

However calling dso__data_fd() in dso__data_read_offset() will hurt
performance as it grabs a global lock everytime. So factor out the loop
on the binary type in dso__data_fd(), and call it from both.

Reported-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1432137821-10853-1-git-send-email-namhyung@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/dso.c | 59 ++++++++++++++++++++++++++++-----------------------
1 file changed, 32 insertions(+), 27 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 1b96c8d..516e0c2 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -440,15 +440,7 @@ void dso__data_close(struct dso *dso)
pthread_mutex_unlock(&dso__data_open_lock);
}

-/**
- * dso__data_fd - Get dso's data file descriptor
- * @dso: dso object
- * @machine: machine object
- *
- * External interface to find dso's file, open it and
- * returns file descriptor.
- */
-int dso__data_fd(struct dso *dso, struct machine *machine)
+static void try_to_open_dso(struct dso *dso, struct machine *machine)
{
enum dso_binary_type binary_type_data[] = {
DSO_BINARY_TYPE__BUILD_ID_CACHE,
@@ -457,13 +449,8 @@ int dso__data_fd(struct dso *dso, struct machine *machine)
};
int i = 0;

- if (dso->data.status == DSO_DATA_STATUS_ERROR)
- return -1;
-
- pthread_mutex_lock(&dso__data_open_lock);
-
if (dso->data.fd >= 0)
- goto out;
+ return;

if (dso->binary_type != DSO_BINARY_TYPE__NOT_FOUND) {
dso->data.fd = open_dso(dso, machine);
@@ -483,8 +470,25 @@ out:
dso->data.status = DSO_DATA_STATUS_OK;
else
dso->data.status = DSO_DATA_STATUS_ERROR;
+}
+
+/**
+ * dso__data_fd - Get dso's data file descriptor
+ * @dso: dso object
+ * @machine: machine object
+ *
+ * External interface to find dso's file, open it and
+ * returns file descriptor.
+ */
+int dso__data_fd(struct dso *dso, struct machine *machine)
+{
+ if (dso->data.status == DSO_DATA_STATUS_ERROR)
+ return -1;

+ pthread_mutex_lock(&dso__data_open_lock);
+ try_to_open_dso(dso, machine);
pthread_mutex_unlock(&dso__data_open_lock);
+
return dso->data.fd;
}

@@ -609,13 +613,12 @@ dso_cache__read(struct dso *dso, struct machine *machine,
* dso->data.fd might be closed if other thread opened another
* file (dso) due to open file limit (RLIMIT_NOFILE).
*/
+ try_to_open_dso(dso, machine);
+
if (dso->data.fd < 0) {
- dso->data.fd = open_dso(dso, machine);
- if (dso->data.fd < 0) {
- ret = -errno;
- dso->data.status = DSO_DATA_STATUS_ERROR;
- break;
- }
+ ret = -errno;
+ dso->data.status = DSO_DATA_STATUS_ERROR;
+ break;
}

cache_offset = offset & DSO__DATA_CACHE_MASK;
@@ -702,19 +705,21 @@ static int data_file_size(struct dso *dso, struct machine *machine)
if (dso->data.file_size)
return 0;

+ if (dso->data.status == DSO_DATA_STATUS_ERROR)
+ return -1;
+
pthread_mutex_lock(&dso__data_open_lock);

/*
* dso->data.fd might be closed if other thread opened another
* file (dso) due to open file limit (RLIMIT_NOFILE).
*/
+ try_to_open_dso(dso, machine);
+
if (dso->data.fd < 0) {
- dso->data.fd = open_dso(dso, machine);
- if (dso->data.fd < 0) {
- ret = -errno;
- dso->data.status = DSO_DATA_STATUS_ERROR;
- goto out;
- }
+ ret = -errno;
+ dso->data.status = DSO_DATA_STATUS_ERROR;
+ goto out;
}

if (fstat(dso->data.fd, &st) < 0) {
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/