* [PATCH v6 bpf-next 1/3] bpf: add a new API libbpf_num_possible_cpus()
2019-06-11 0:56 [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Hechao Li
@ 2019-06-11 0:56 ` Hechao Li
2019-06-11 0:56 ` [PATCH v6 bpf-next 2/3] selftests/bpf: remove bpf_util.h from BPF C progs Hechao Li
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Hechao Li @ 2019-06-11 0:56 UTC (permalink / raw)
To: bpf; +Cc: netdev, daniel, ast, kernel-team, Hechao Li
Adding a new API libbpf_num_possible_cpus() that helps user with
per-CPU map operations.
Signed-off-by: Hechao Li <hechaol@fb.com>
---
tools/lib/bpf/libbpf.c | 57 ++++++++++++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 16 +++++++++++
tools/lib/bpf/libbpf.map | 1 +
3 files changed, 74 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index ba89d9727137..dd8b2cd5d3a7 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -3827,3 +3827,60 @@ void bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear)
desc->array_offset, addr);
}
}
+
+int libbpf_num_possible_cpus(void)
+{
+ static const char *fcpu = "/sys/devices/system/cpu/possible";
+ int len = 0, n = 0, il = 0, ir = 0;
+ unsigned int start = 0, end = 0;
+ static int cpus;
+ char buf[128];
+ int error = 0;
+ int fd = -1;
+
+ if (cpus > 0)
+ return cpus;
+
+ fd = open(fcpu, O_RDONLY);
+ if (fd < 0) {
+ error = errno;
+ pr_warning("Failed to open file %s: %s\n",
+ fcpu, strerror(error));
+ return -error;
+ }
+ len = read(fd, buf, sizeof(buf));
+ close(fd);
+ if (len <= 0) {
+ error = len ? errno : EINVAL;
+ pr_warning("Failed to read # of possible cpus from %s: %s\n",
+ fcpu, strerror(error));
+ return -error;
+ }
+ if (len == sizeof(buf)) {
+ pr_warning("File %s size overflow\n", fcpu);
+ return -EOVERFLOW;
+ }
+ buf[len] = '\0';
+
+ for (ir = 0, cpus = 0; ir <= len; ir++) {
+ /* Each sub string separated by ',' has format \d+-\d+ or \d+ */
+ if (buf[ir] == ',' || buf[ir] == '\0') {
+ buf[ir] = '\0';
+ n = sscanf(&buf[il], "%u-%u", &start, &end);
+ if (n <= 0) {
+ pr_warning("Failed to get # CPUs from %s\n",
+ &buf[il]);
+ return -EINVAL;
+ } else if (n == 1) {
+ end = start;
+ }
+ cpus += end - start + 1;
+ il = ir + 1;
+ }
+ }
+ if (cpus <= 0) {
+ pr_warning("Invalid #CPUs %d from %s\n", cpus, fcpu);
+ return -EINVAL;
+ }
+ return cpus;
+}
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 1af0d48178c8..2e594a0fa961 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -454,6 +454,22 @@ bpf_program__bpil_addr_to_offs(struct bpf_prog_info_linear *info_linear);
LIBBPF_API void
bpf_program__bpil_offs_to_addr(struct bpf_prog_info_linear *info_linear);
+/*
+ * A helper function to get the number of possible CPUs before looking up
+ * per-CPU maps. Negative errno is returned on failure.
+ *
+ * Example usage:
+ *
+ * int ncpus = libbpf_num_possible_cpus();
+ * if (ncpus < 0) {
+ * // error handling
+ * }
+ * long values[ncpus];
+ * bpf_map_lookup_elem(per_cpu_map_fd, key, values);
+ *
+ */
+LIBBPF_API int libbpf_num_possible_cpus(void);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 46dcda89df21..2c6d835620d2 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -172,4 +172,5 @@ LIBBPF_0.0.4 {
btf_dump__new;
btf__parse_elf;
bpf_object__load_xattr;
+ libbpf_num_possible_cpus;
} LIBBPF_0.0.3;
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v6 bpf-next 2/3] selftests/bpf: remove bpf_util.h from BPF C progs
2019-06-11 0:56 [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Hechao Li
2019-06-11 0:56 ` [PATCH v6 bpf-next 1/3] bpf: add " Hechao Li
@ 2019-06-11 0:56 ` Hechao Li
2019-06-11 0:56 ` [PATCH v6 bpf-next 3/3] bpf: use libbpf_num_possible_cpus internally Hechao Li
2019-06-11 8:54 ` [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Daniel Borkmann
3 siblings, 0 replies; 5+ messages in thread
From: Hechao Li @ 2019-06-11 0:56 UTC (permalink / raw)
To: bpf; +Cc: netdev, daniel, ast, kernel-team, Hechao Li
Though currently there is no problem including bpf_util.h in kernel
space BPF C programs, in next patch in this stack, I will reuse
libbpf_num_possible_cpus() in bpf_util.h thus include libbpf.h in it,
which will cause BPF C programs compile error. Therefore I will first
remove bpf_util.h from all test BPF programs.
This can also make it clear that bpf_util.h is a user-space utility
while bpf_helpers.h is a kernel space utility.
Signed-off-by: Hechao Li <hechaol@fb.com>
---
tools/testing/selftests/bpf/bpf_endian.h | 1 +
tools/testing/selftests/bpf/progs/sockmap_parse_prog.c | 1 -
tools/testing/selftests/bpf/progs/sockmap_tcp_msg_prog.c | 2 +-
tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c | 1 -
tools/testing/selftests/bpf/progs/test_sysctl_prog.c | 5 ++++-
5 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/bpf_endian.h b/tools/testing/selftests/bpf/bpf_endian.h
index b25595ea4a78..05f036df8a4c 100644
--- a/tools/testing/selftests/bpf/bpf_endian.h
+++ b/tools/testing/selftests/bpf/bpf_endian.h
@@ -2,6 +2,7 @@
#ifndef __BPF_ENDIAN__
#define __BPF_ENDIAN__
+#include <linux/stddef.h>
#include <linux/swab.h>
/* LLVM's BPF target selects the endianness of the CPU
diff --git a/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c b/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c
index ed3e4a551c57..9390e0244259 100644
--- a/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c
+++ b/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c
@@ -1,6 +1,5 @@
#include <linux/bpf.h>
#include "bpf_helpers.h"
-#include "bpf_util.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
diff --git a/tools/testing/selftests/bpf/progs/sockmap_tcp_msg_prog.c b/tools/testing/selftests/bpf/progs/sockmap_tcp_msg_prog.c
index 65fbfdb6cd3a..e80484d98a1a 100644
--- a/tools/testing/selftests/bpf/progs/sockmap_tcp_msg_prog.c
+++ b/tools/testing/selftests/bpf/progs/sockmap_tcp_msg_prog.c
@@ -1,6 +1,6 @@
#include <linux/bpf.h>
+
#include "bpf_helpers.h"
-#include "bpf_util.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
diff --git a/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c b/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c
index bdc22be46f2e..d85c874ef25e 100644
--- a/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c
+++ b/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c
@@ -1,6 +1,5 @@
#include <linux/bpf.h>
#include "bpf_helpers.h"
-#include "bpf_util.h"
#include "bpf_endian.h"
int _version SEC("version") = 1;
diff --git a/tools/testing/selftests/bpf/progs/test_sysctl_prog.c b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
index a295cad805d7..5cbbff416998 100644
--- a/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
+++ b/tools/testing/selftests/bpf/progs/test_sysctl_prog.c
@@ -8,7 +8,6 @@
#include <linux/bpf.h>
#include "bpf_helpers.h"
-#include "bpf_util.h"
/* Max supported length of a string with unsigned long in base 10 (pow2 - 1). */
#define MAX_ULONG_STR_LEN 0xF
@@ -16,6 +15,10 @@
/* Max supported length of sysctl value string (pow2). */
#define MAX_VALUE_STR_LEN 0x40
+#ifndef ARRAY_SIZE
+#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
+#endif
+
static __always_inline int is_tcp_mem(struct bpf_sysctl *ctx)
{
char tcp_mem_name[] = "net/ipv4/tcp_mem";
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* [PATCH v6 bpf-next 3/3] bpf: use libbpf_num_possible_cpus internally
2019-06-11 0:56 [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Hechao Li
2019-06-11 0:56 ` [PATCH v6 bpf-next 1/3] bpf: add " Hechao Li
2019-06-11 0:56 ` [PATCH v6 bpf-next 2/3] selftests/bpf: remove bpf_util.h from BPF C progs Hechao Li
@ 2019-06-11 0:56 ` Hechao Li
2019-06-11 8:54 ` [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Daniel Borkmann
3 siblings, 0 replies; 5+ messages in thread
From: Hechao Li @ 2019-06-11 0:56 UTC (permalink / raw)
To: bpf; +Cc: netdev, daniel, ast, kernel-team, Hechao Li
Use the newly added bpf_num_possible_cpus() in bpftool and selftests
and remove duplicate implementations.
Signed-off-by: Hechao Li <hechaol@fb.com>
---
tools/bpf/bpftool/common.c | 53 +++-----------------------
tools/testing/selftests/bpf/bpf_util.h | 37 +++---------------
2 files changed, 10 insertions(+), 80 deletions(-)
diff --git a/tools/bpf/bpftool/common.c b/tools/bpf/bpftool/common.c
index f7261fad45c1..5215e0870bcb 100644
--- a/tools/bpf/bpftool/common.c
+++ b/tools/bpf/bpftool/common.c
@@ -21,6 +21,7 @@
#include <sys/vfs.h>
#include <bpf.h>
+#include <libbpf.h> /* libbpf_num_possible_cpus */
#include "main.h"
@@ -439,57 +440,13 @@ unsigned int get_page_size(void)
unsigned int get_possible_cpus(void)
{
- static unsigned int result;
- char buf[128];
- long int n;
- char *ptr;
- int fd;
-
- if (result)
- return result;
-
- fd = open("/sys/devices/system/cpu/possible", O_RDONLY);
- if (fd < 0) {
- p_err("can't open sysfs possible cpus");
- exit(-1);
- }
-
- n = read(fd, buf, sizeof(buf));
- if (n < 2) {
- p_err("can't read sysfs possible cpus");
- exit(-1);
- }
- close(fd);
+ int cpus = libbpf_num_possible_cpus();
- if (n == sizeof(buf)) {
- p_err("read sysfs possible cpus overflow");
+ if (cpus < 0) {
+ p_err("Can't get # of possible cpus: %s", strerror(-cpus));
exit(-1);
}
-
- ptr = buf;
- n = 0;
- while (*ptr && *ptr != '\n') {
- unsigned int a, b;
-
- if (sscanf(ptr, "%u-%u", &a, &b) == 2) {
- n += b - a + 1;
-
- ptr = strchr(ptr, '-') + 1;
- } else if (sscanf(ptr, "%u", &a) == 1) {
- n++;
- } else {
- assert(0);
- }
-
- while (isdigit(*ptr))
- ptr++;
- if (*ptr == ',')
- ptr++;
- }
-
- result = n;
-
- return result;
+ return cpus;
}
static char *
diff --git a/tools/testing/selftests/bpf/bpf_util.h b/tools/testing/selftests/bpf/bpf_util.h
index a29206ebbd13..ec219f84e041 100644
--- a/tools/testing/selftests/bpf/bpf_util.h
+++ b/tools/testing/selftests/bpf/bpf_util.h
@@ -6,44 +6,17 @@
#include <stdlib.h>
#include <string.h>
#include <errno.h>
+#include <libbpf.h> /* libbpf_num_possible_cpus */
static inline unsigned int bpf_num_possible_cpus(void)
{
- static const char *fcpu = "/sys/devices/system/cpu/possible";
- unsigned int start, end, possible_cpus = 0;
- char buff[128];
- FILE *fp;
- int len, n, i, j = 0;
+ int possible_cpus = libbpf_num_possible_cpus();
- fp = fopen(fcpu, "r");
- if (!fp) {
- printf("Failed to open %s: '%s'!\n", fcpu, strerror(errno));
+ if (possible_cpus < 0) {
+ printf("Failed to get # of possible cpus: '%s'!\n",
+ strerror(-possible_cpus));
exit(1);
}
-
- if (!fgets(buff, sizeof(buff), fp)) {
- printf("Failed to read %s!\n", fcpu);
- exit(1);
- }
-
- len = strlen(buff);
- for (i = 0; i <= len; i++) {
- if (buff[i] == ',' || buff[i] == '\0') {
- buff[i] = '\0';
- n = sscanf(&buff[j], "%u-%u", &start, &end);
- if (n <= 0) {
- printf("Failed to retrieve # possible CPUs!\n");
- exit(1);
- } else if (n == 1) {
- end = start;
- }
- possible_cpus += end - start + 1;
- j = i + 1;
- }
- }
-
- fclose(fp);
-
return possible_cpus;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus()
2019-06-11 0:56 [PATCH v6 bpf-next 0/3] Add a new API libbpf_num_possible_cpus() Hechao Li
` (2 preceding siblings ...)
2019-06-11 0:56 ` [PATCH v6 bpf-next 3/3] bpf: use libbpf_num_possible_cpus internally Hechao Li
@ 2019-06-11 8:54 ` Daniel Borkmann
3 siblings, 0 replies; 5+ messages in thread
From: Daniel Borkmann @ 2019-06-11 8:54 UTC (permalink / raw)
To: Hechao Li, bpf; +Cc: netdev, ast, kernel-team
On 06/11/2019 02:56 AM, Hechao Li wrote:
> Getting number of possible CPUs is commonly used for per-CPU BPF maps
> and perf_event_maps. Add a new API libbpf_num_possible_cpus() that
> helps user with per-CPU related operations and remove duplicate
> implementations in bpftool and selftests.
>
> v2: Save errno before calling pr_warning in case it is changed.
> v3: Make sure libbpf_num_possible_cpus never returns 0 so that user only
> has to check if ret value < 0.
> v4: Fix error code when reading 0 bytes from possible CPU file.
> v5: Fix selftests compliation issue.
> v6: Split commit to reuse libbpf_num_possible_cpus() into two commits:
> One commit to remove bpf_util.h from test BPF C programs.
> One commit to reuse libbpf_num_possible_cpus() in bpftools
> and bpf_util.h.
>
>
> Hechao Li (3):
> bpf: add a new API libbpf_num_possible_cpus()
> selftests/bpf: remove bpf_util.h from BPF C progs
> bpf: use libbpf_num_possible_cpus internally
>
> tools/bpf/bpftool/common.c | 53 ++---------------
> tools/lib/bpf/libbpf.c | 57 +++++++++++++++++++
> tools/lib/bpf/libbpf.h | 16 ++++++
> tools/lib/bpf/libbpf.map | 1 +
> tools/testing/selftests/bpf/bpf_endian.h | 1 +
> tools/testing/selftests/bpf/bpf_util.h | 37 ++----------
> .../selftests/bpf/progs/sockmap_parse_prog.c | 1 -
> .../bpf/progs/sockmap_tcp_msg_prog.c | 2 +-
> .../bpf/progs/sockmap_verdict_prog.c | 1 -
> .../selftests/bpf/progs/test_sysctl_prog.c | 5 +-
> 10 files changed, 90 insertions(+), 84 deletions(-)
>
Applied, thanks!
^ permalink raw reply [flat|nested] 5+ messages in thread