[PATCH 75/86] perf header: Add a buffer to struct feat_fd

Arnaldo Carvalho de Melo
2017-07-19T14:37:28Z

From: David Carrillo-Cisneros <davidcc@google.com>

Extend struct feat_fd to use a temporal buffer in pipe-mode, instead of
perf.data's file descriptor.

The header features build_id and aux_trace already have logic to print
in file-mode that heavily rely on lseek the file. For now, leave such
features inactive in pipe-mode and print a warning if their functions
are called in pipe-mode.

Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Acked-by: David Ahern <dsahern@gmail.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Simon Que <sque@chromium.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170718042549.145161-13-davidcc@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/header.c | 75 ++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 70 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index d5359e3384e3..5e6d4d29a7a3 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -62,6 +62,7 @@ struct perf_file_attr {
struct feat_fd {
struct perf_header *ph;
int fd;
+ void *buf; /* Either buf != NULL or fd >= 0 */
ssize_t offset;
size_t size;
};
@@ -81,19 +82,52 @@ bool perf_header__has_feat(const struct perf_header *header, int feat)
return test_bit(feat, header->adds_features);
}

-/* Return: 0 if succeded, -ERR if failed. */
-int do_write(struct feat_fd *ff, const void *buf, size_t size)
+static int __do_write_fd(struct feat_fd *ff, const void *buf, size_t size)
{
- ssize_t ret;
+ ssize_t ret = writen(ff->fd, buf, size);

- ret = writen(ff->fd, buf, size);
if (ret != (ssize_t)size)
return ret < 0 ? (int)ret : -1;
+ return 0;
+}
+
+static int __do_write_buf(struct feat_fd *ff, const void *buf, size_t size)
+{
+ /* struct perf_event_header::size is u16 */
+ const size_t max_size = 0xffff - sizeof(struct perf_event_header);
+ size_t new_size = ff->size;
+ void *addr;
+
+ if (size + ff->offset > max_size)
+ return -E2BIG;
+
+ while (size > (new_size - ff->offset))
+ new_size <<= 1;
+ new_size = min(max_size, new_size);
+
+ if (ff->size < new_size) {
+ addr = realloc(ff->buf, new_size);
+ if (!addr)
+ return -ENOMEM;
+ ff->buf = addr;
+ ff->size = new_size;
+ }
+
+ memcpy(ff->buf + ff->offset, buf, size);
+ ff->offset += size;

return 0;
}

/* Return: 0 if succeded, -ERR if failed. */
+int do_write(struct feat_fd *ff, const void *buf, size_t size)
+{
+ if (!ff->buf)
+ return __do_write_fd(ff, buf, size);
+ return __do_write_buf(ff, buf, size);
+}
+
+/* Return: 0 if succeded, -ERR if failed. */
int write_padded(struct feat_fd *ff, const void *bf,
size_t count, size_t count_aligned)
{
@@ -126,7 +160,7 @@ static int do_write_string(struct feat_fd *ff, const char *str)
return write_padded(ff, str, olen, len);
}

-static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+static int __do_read_fd(struct feat_fd *ff, void *addr, ssize_t size)
{
ssize_t ret = readn(ff->fd, addr, size);

@@ -135,6 +169,25 @@ static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
return 0;
}

+static int __do_read_buf(struct feat_fd *ff, void *addr, ssize_t size)
+{
+ if (size > (ssize_t)ff->size - ff->offset)
+ return -1;
+
+ memcpy(addr, ff->buf + ff->offset, size);
+ ff->offset += size;
+
+ return 0;
+
+}
+
+static int __do_read(struct feat_fd *ff, void *addr, ssize_t size)
+{
+ if (!ff->buf)
+ return __do_read_fd(ff, addr, size);
+ return __do_read_buf(ff, addr, size);
+}
+
static int do_read_u32(struct feat_fd *ff, u32 *addr)
{
int ret;
@@ -189,6 +242,9 @@ static char *do_read_string(struct feat_fd *ff)
static int write_tracing_data(struct feat_fd *ff,
struct perf_evlist *evlist)
{
+ if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+ return -1;
+
return read_tracing_data(ff->fd, &evlist->entries);
}

@@ -203,6 +259,9 @@ static int write_build_id(struct feat_fd *ff,
if (!perf_session__read_build_ids(session, true))
return -1;

+ if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+ return -1;
+
err = perf_session__write_buildid_table(session, ff);
if (err < 0) {
pr_debug("failed to write buildid table\n");
@@ -912,6 +971,9 @@ static int write_auxtrace(struct feat_fd *ff,
struct perf_session *session;
int err;

+ if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+ return -1;
+
session = container_of(ff->ph, struct perf_session, header);

err = auxtrace_index__write(ff->fd, &session->auxtrace_index);
@@ -2197,6 +2259,9 @@ static int do_write_feat(struct feat_fd *ff, int type,
if (!feat_ops[type].write)
return -1;

+ if (WARN(ff->buf, "Error: calling %s in pipe-mode.\n", __func__))
+ return -1;
+
(*p)->offset = lseek(ff->fd, 0, SEEK_CUR);

err = feat_ops[type].write(ff, evlist);
--
2.9.4