2022-04-22 17:16:21

by [email protected]

[permalink] [raw]
Subject: [PATCH 2/7] libperf: Introduce perf_{evsel, evlist}__open_opt with extensible struct opts

Introduce perf_{evsel, evlist}__open_opt with extensible structure opts.
The mechanism of the extensible structure opts imitates
tools/lib/bpf/libbpf.h. Currently, only open_flags is supported for the
opts structure.

Signed-off-by: Shunsuke Nakamura <[email protected]>
---
tools/lib/perf/Documentation/libperf.txt | 10 ++++++
tools/lib/perf/evlist.c | 20 +++++++++++
tools/lib/perf/evsel.c | 25 +++++++++++++-
tools/lib/perf/include/perf/evlist.h | 3 ++
tools/lib/perf/include/perf/evsel.h | 22 ++++++++++++
tools/lib/perf/internal.h | 44 ++++++++++++++++++++++++
tools/lib/perf/libperf.map | 2 ++
7 files changed, 125 insertions(+), 1 deletion(-)

diff --git a/tools/lib/perf/Documentation/libperf.txt b/tools/lib/perf/Documentation/libperf.txt
index a8f1a237931b..6ca91ca94e01 100644
--- a/tools/lib/perf/Documentation/libperf.txt
+++ b/tools/lib/perf/Documentation/libperf.txt
@@ -132,6 +132,16 @@ SYNOPSIS
};
};

+ struct perf_evsel_open_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+
+ unsigned long open_flags; /* perf_event_open flags */
+ };
+ #define perf_evsel_open_opts__last_field open_flags
+
+ #define LIBPERF_OPTS(TYPE, NAME, ...)
+
struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
void perf_evsel__delete(struct perf_evsel *evsel);
int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
diff --git a/tools/lib/perf/evlist.c b/tools/lib/perf/evlist.c
index a09315538a30..bf9343acb799 100644
--- a/tools/lib/perf/evlist.c
+++ b/tools/lib/perf/evlist.c
@@ -665,3 +665,23 @@ void perf_evlist__set_leader(struct perf_evlist *evlist)
__perf_evlist__set_leader(&evlist->entries, first);
}
}
+
+int perf_evlist__open_opts(struct perf_evlist *evlist,
+ struct perf_evsel_open_opts *opts)
+{
+ struct perf_evsel *evsel;
+ int err;
+
+ perf_evlist__for_each_entry(evlist, evsel) {
+ err = perf_evsel__open_opts(evsel, evsel->cpus,
+ evsel->threads, opts);
+ if (err < 0)
+ goto out_err;
+ }
+
+ return 0;
+
+out_err:
+ perf_evlist__close(evlist);
+ return err;
+}
diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
index 210ea7c06ce8..00c0cea43b52 100644
--- a/tools/lib/perf/evsel.c
+++ b/tools/lib/perf/evsel.c
@@ -16,8 +16,12 @@
#include <internal/lib.h>
#include <linux/string.h>
#include <sys/ioctl.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/types.h>
#include <sys/mman.h>
#include <asm/bug.h>
+#include "internal.h"

void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
int idx)
@@ -26,6 +30,7 @@ void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
evsel->attr = *attr;
evsel->idx = idx;
evsel->leader = evsel;
+ evsel->open_flags = 0;
}

struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr)
@@ -158,7 +163,7 @@ int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,

fd = sys_perf_event_open(&evsel->attr,
threads->map[thread].pid,
- cpu, group_fd, 0);
+ cpu, group_fd, evsel->open_flags);

if (fd < 0)
return -errno;
@@ -454,3 +459,21 @@ void perf_counts_values__scale(struct perf_counts_values *count,
if (pscaled)
*pscaled = scaled;
}
+
+int perf_evsel__open_opts(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
+ struct perf_thread_map *threads,
+ struct perf_evsel_open_opts *opts)
+{
+ int err = 0;
+
+ if (!OPTS_VALID(opts, perf_evsel_open_opts)) {
+ err = -EINVAL;
+ return err;
+ }
+
+ evsel->open_flags = OPTS_GET(opts, open_flags, 0);
+
+ err = perf_evsel__open(evsel, cpus, threads);
+
+ return err;
+}
diff --git a/tools/lib/perf/include/perf/evlist.h b/tools/lib/perf/include/perf/evlist.h
index 9ca399d49bb4..6eff1e9b3481 100644
--- a/tools/lib/perf/include/perf/evlist.h
+++ b/tools/lib/perf/include/perf/evlist.h
@@ -9,6 +9,7 @@ struct perf_evlist;
struct perf_evsel;
struct perf_cpu_map;
struct perf_thread_map;
+struct perf_evsel_open_opts;

LIBPERF_API void perf_evlist__add(struct perf_evlist *evlist,
struct perf_evsel *evsel);
@@ -47,4 +48,6 @@ LIBPERF_API struct perf_mmap *perf_evlist__next_mmap(struct perf_evlist *evlist,
(pos) = perf_evlist__next_mmap((evlist), (pos), overwrite))

LIBPERF_API void perf_evlist__set_leader(struct perf_evlist *evlist);
+LIBPERF_API int perf_evlist__open_opts(struct perf_evlist *evlist,
+ struct perf_evsel_open_opts *opts);
#endif /* __LIBPERF_EVLIST_H */
diff --git a/tools/lib/perf/include/perf/evsel.h b/tools/lib/perf/include/perf/evsel.h
index 2a9516b42d15..1140df4d2578 100644
--- a/tools/lib/perf/include/perf/evsel.h
+++ b/tools/lib/perf/include/perf/evsel.h
@@ -5,6 +5,7 @@
#include <stdint.h>
#include <perf/core.h>
#include <stdbool.h>
+#include <signal.h>
#include <linux/types.h>

struct perf_evsel;
@@ -23,6 +24,23 @@ struct perf_counts_values {
};
};

+struct perf_evsel_open_opts {
+ /* size of this struct, for forward/backward compatibility */
+ size_t sz;
+
+ unsigned long open_flags; /* perf_event_open flags */
+};
+#define perf_evsel_open_opts__last_field open_flags
+
+#define LIBPERF_OPTS(TYPE, NAME, ...) \
+ struct TYPE NAME = ({ \
+ memset(&NAME, 0, sizeof(struct TYPE)); \
+ (struct TYPE) { \
+ .sz = sizeof(struct TYPE), \
+ __VA_ARGS__ \
+ }; \
+ })
+
LIBPERF_API struct perf_evsel *perf_evsel__new(struct perf_event_attr *attr);
LIBPERF_API void perf_evsel__delete(struct perf_evsel *evsel);
LIBPERF_API int perf_evsel__open(struct perf_evsel *evsel, struct perf_cpu_map *cpus,
@@ -43,5 +61,9 @@ LIBPERF_API struct perf_thread_map *perf_evsel__threads(struct perf_evsel *evsel
LIBPERF_API struct perf_event_attr *perf_evsel__attr(struct perf_evsel *evsel);
LIBPERF_API void perf_counts_values__scale(struct perf_counts_values *count,
bool scale, __s8 *pscaled);
+LIBPERF_API int perf_evsel__open_opts(struct perf_evsel *evsel,
+ struct perf_cpu_map *cpus,
+ struct perf_thread_map *threads,
+ struct perf_evsel_open_opts *opts);

#endif /* __LIBPERF_EVSEL_H */
diff --git a/tools/lib/perf/internal.h b/tools/lib/perf/internal.h
index 2c27e158de6b..4b91a087ed62 100644
--- a/tools/lib/perf/internal.h
+++ b/tools/lib/perf/internal.h
@@ -20,4 +20,48 @@ do { \
#define pr_debug2(fmt, ...) __pr(LIBPERF_DEBUG2, fmt, ##__VA_ARGS__)
#define pr_debug3(fmt, ...) __pr(LIBPERF_DEBUG3, fmt, ##__VA_ARGS__)

+static inline bool libperf_is_mem_zeroed(const char *p, ssize_t len)
+{
+ while (len > 0) {
+ if (*p)
+ return false;
+ p++;
+ len--;
+ }
+ return true;
+}
+
+static inline bool libperf_validate_opts(const char *opts,
+ size_t opts_sz, size_t user_sz,
+ const char *type_name)
+{
+ if (user_sz < sizeof(size_t)) {
+ pr_warning("%s size (%zu) is too small\n", type_name, user_sz);
+ return false;
+ }
+ if (!libperf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {
+ pr_warning("%s has non-zero extra bytes\n", type_name);
+ return false;
+ }
+ return true;
+}
+
+#define offsetofend(TYPE, FIELD) \
+ (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
+
+#define OPTS_VALID(opts, type) \
+ (!(opts) || libperf_validate_opts((const char *)opts, \
+ offsetofend(struct type, \
+ type##__last_field), \
+ (opts)->sz, #type))
+#define OPTS_HAS(opts, field) \
+ ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
+#define OPTS_GET(opts, field, fallback_value) \
+ (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)
+#define OPTS_SET(opts, field, value) \
+ do { \
+ if (OPTS_HAS(opts, field)) \
+ (opts)->field = value; \
+ } while (0)
+
#endif /* __LIBPERF_INTERNAL_H */
diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
index 190b56ae923a..eeeb3075e092 100644
--- a/tools/lib/perf/libperf.map
+++ b/tools/lib/perf/libperf.map
@@ -25,6 +25,7 @@ LIBPERF_0.0.1 {
perf_evsel__enable;
perf_evsel__disable;
perf_evsel__open;
+ perf_evsel__open_opts;
perf_evsel__close;
perf_evsel__mmap;
perf_evsel__munmap;
@@ -36,6 +37,7 @@ LIBPERF_0.0.1 {
perf_evlist__new;
perf_evlist__delete;
perf_evlist__open;
+ perf_evlist__open_opts;
perf_evlist__close;
perf_evlist__enable;
perf_evlist__disable;
--
2.25.1


2022-05-21 13:30:20

by Namhyung Kim

[permalink] [raw]
Subject: Re: [PATCH 2/7] libperf: Introduce perf_{evsel, evlist}__open_opt with extensible struct opts

Hello,

On Fri, Apr 22, 2022 at 2:44 AM Shunsuke Nakamura
<[email protected]> wrote:
>
> Introduce perf_{evsel, evlist}__open_opt with extensible structure opts.
> The mechanism of the extensible structure opts imitates
> tools/lib/bpf/libbpf.h. Currently, only open_flags is supported for the
> opts structure.
>
> Signed-off-by: Shunsuke Nakamura <[email protected]>
> ---
[SNIP]
> diff --git a/tools/lib/perf/evsel.c b/tools/lib/perf/evsel.c
> index 210ea7c06ce8..00c0cea43b52 100644
> --- a/tools/lib/perf/evsel.c
> +++ b/tools/lib/perf/evsel.c
> @@ -16,8 +16,12 @@
> #include <internal/lib.h>
> #include <linux/string.h>
> #include <sys/ioctl.h>
> +#include <signal.h>
> +#include <fcntl.h>
> +#include <sys/types.h>
> #include <sys/mman.h>
> #include <asm/bug.h>
> +#include "internal.h"
>
> void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
> int idx)
> @@ -26,6 +30,7 @@ void perf_evsel__init(struct perf_evsel *evsel, struct perf_event_attr *attr,
> evsel->attr = *attr;
> evsel->idx = idx;
> evsel->leader = evsel;
> + evsel->open_flags = 0;

In general, you don't need to reset it to zero as it's allocated with
zalloc().

> }
>
[SNIP]
> diff --git a/tools/lib/perf/internal.h b/tools/lib/perf/internal.h
> index 2c27e158de6b..4b91a087ed62 100644
> --- a/tools/lib/perf/internal.h
> +++ b/tools/lib/perf/internal.h
> @@ -20,4 +20,48 @@ do { \
> #define pr_debug2(fmt, ...) __pr(LIBPERF_DEBUG2, fmt, ##__VA_ARGS__)
> #define pr_debug3(fmt, ...) __pr(LIBPERF_DEBUG3, fmt, ##__VA_ARGS__)
>
> +static inline bool libperf_is_mem_zeroed(const char *p, ssize_t len)
> +{
> + while (len > 0) {
> + if (*p)
> + return false;
> + p++;
> + len--;
> + }
> + return true;
> +}
> +
> +static inline bool libperf_validate_opts(const char *opts,
> + size_t opts_sz, size_t user_sz,
> + const char *type_name)
> +{
> + if (user_sz < sizeof(size_t)) {
> + pr_warning("%s size (%zu) is too small\n", type_name, user_sz);
> + return false;
> + }
> + if (!libperf_is_mem_zeroed(opts + opts_sz, (ssize_t)user_sz - opts_sz)) {

I don't think the cast is necessary since it'll be promoted again
to size_t due to opts_sz. Instead, we can check if user_sz is
greater than opts_sz explicitly and call the function.

> + pr_warning("%s has non-zero extra bytes\n", type_name);
> + return false;
> + }
> + return true;
> +}
> +
> +#define offsetofend(TYPE, FIELD) \
> + (offsetof(TYPE, FIELD) + sizeof(((TYPE *)0)->FIELD))
> +
> +#define OPTS_VALID(opts, type) \
> + (!(opts) || libperf_validate_opts((const char *)opts, \
> + offsetofend(struct type, \
> + type##__last_field), \
> + (opts)->sz, #type))
> +#define OPTS_HAS(opts, field) \
> + ((opts) && opts->sz >= offsetofend(typeof(*(opts)), field))
> +#define OPTS_GET(opts, field, fallback_value) \
> + (OPTS_HAS(opts, field) ? (opts)->field : fallback_value)

It'd be nice if you add a blank line between the macros.

Thanks,
Namhyung


> +#define OPTS_SET(opts, field, value) \
> + do { \
> + if (OPTS_HAS(opts, field)) \
> + (opts)->field = value; \
> + } while (0)
> +
> #endif /* __LIBPERF_INTERNAL_H */
> diff --git a/tools/lib/perf/libperf.map b/tools/lib/perf/libperf.map
> index 190b56ae923a..eeeb3075e092 100644
> --- a/tools/lib/perf/libperf.map
> +++ b/tools/lib/perf/libperf.map
> @@ -25,6 +25,7 @@ LIBPERF_0.0.1 {
> perf_evsel__enable;
> perf_evsel__disable;
> perf_evsel__open;
> + perf_evsel__open_opts;
> perf_evsel__close;
> perf_evsel__mmap;
> perf_evsel__munmap;
> @@ -36,6 +37,7 @@ LIBPERF_0.0.1 {
> perf_evlist__new;
> perf_evlist__delete;
> perf_evlist__open;
> + perf_evlist__open_opts;
> perf_evlist__close;
> perf_evlist__enable;
> perf_evlist__disable;
> --
> 2.25.1
>