[PATCH 5.7 118/265] samples/bpf: xdp_redirect_cpu: Set MAX_CPUS according to NR_CPUS

Sasha Levin
2020-06-29T21:50:44Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit 6a09815428547657f3ffd2f5c31ac2a191e7fdf3 ]

xdp_redirect_cpu is currently failing in bpf_prog_load_xattr()
allocating cpu_map map if CONFIG_NR_CPUS is less than 64 since
cpu_map_alloc() requires max_entries to be less than NR_CPUS.
Set cpu_map max_entries according to NR_CPUS in xdp_redirect_cpu_kern.c
and get currently running cpus in xdp_redirect_cpu_user.c

Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/374472755001c260158c4e4b22f193bdd3c56fb7.1589300442.git.lorenzo@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
samples/bpf/xdp_redirect_cpu_kern.c | 2 +-
samples/bpf/xdp_redirect_cpu_user.c | 29 ++++++++++++++++-------------
2 files changed, 17 insertions(+), 14 deletions(-)

diff --git a/samples/bpf/xdp_redirect_cpu_kern.c b/samples/bpf/xdp_redirect_cpu_kern.c
index 313a8fe6d125c..2baf8db1f7e70 100644
--- a/samples/bpf/xdp_redirect_cpu_kern.c
+++ b/samples/bpf/xdp_redirect_cpu_kern.c
@@ -15,7 +15,7 @@
#include <bpf/bpf_helpers.h>
#include "hash_func01.h"

-#define MAX_CPUS 64 /* WARNING - sync with _user.c */
+#define MAX_CPUS NR_CPUS

/* Special map type that can XDP_REDIRECT frames to another CPU */
struct {
diff --git a/samples/bpf/xdp_redirect_cpu_user.c b/samples/bpf/xdp_redirect_cpu_user.c
index 15bdf047a2221..9b8f21abeac47 100644
--- a/samples/bpf/xdp_redirect_cpu_user.c
+++ b/samples/bpf/xdp_redirect_cpu_user.c
@@ -13,6 +13,7 @@ static const char *__doc__ =
#include <unistd.h>
#include <locale.h>
#include <sys/resource.h>
+#include <sys/sysinfo.h>
#include <getopt.h>
#include <net/if.h>
#include <time.h>
@@ -24,8 +25,6 @@ static const char *__doc__ =
#include <arpa/inet.h>
#include <linux/if_link.h>

-#define MAX_CPUS 64 /* WARNING - sync with _kern.c */
-
/* How many xdp_progs are defined in _kern.c */
#define MAX_PROG 6

@@ -40,6 +39,7 @@ static char *ifname;
static __u32 prog_id;

static __u32 xdp_flags = XDP_FLAGS_UPDATE_IF_NOEXIST;
+static int n_cpus;
static int cpu_map_fd;
static int rx_cnt_map_fd;
static int redirect_err_cnt_map_fd;
@@ -170,7 +170,7 @@ struct stats_record {
struct record redir_err;
struct record kthread;
struct record exception;
- struct record enq[MAX_CPUS];
+ struct record enq[];
};

static bool map_collect_percpu(int fd, __u32 key, struct record *rec)
@@ -225,10 +225,11 @@ static struct datarec *alloc_record_per_cpu(void)
static struct stats_record *alloc_stats_record(void)
{
struct stats_record *rec;
- int i;
+ int i, size;

- rec = malloc(sizeof(*rec));
- memset(rec, 0, sizeof(*rec));
+ size = sizeof(*rec) + n_cpus * sizeof(struct record);
+ rec = malloc(size);
+ memset(rec, 0, size);
if (!rec) {
fprintf(stderr, "Mem alloc error\n");
exit(EXIT_FAIL_MEM);
@@ -237,7 +238,7 @@ static struct stats_record *alloc_stats_record(void)
rec->redir_err.cpu = alloc_record_per_cpu();
rec->kthread.cpu = alloc_record_per_cpu();
rec->exception.cpu = alloc_record_per_cpu();
- for (i = 0; i < MAX_CPUS; i++)
+ for (i = 0; i < n_cpus; i++)
rec->enq[i].cpu = alloc_record_per_cpu();

return rec;
@@ -247,7 +248,7 @@ static void free_stats_record(struct stats_record *r)
{
int i;

- for (i = 0; i < MAX_CPUS; i++)
+ for (i = 0; i < n_cpus; i++)
free(r->enq[i].cpu);
free(r->exception.cpu);
free(r->kthread.cpu);
@@ -350,7 +351,7 @@ static void stats_print(struct stats_record *stats_rec,
}

/* cpumap enqueue stats */
- for (to_cpu = 0; to_cpu < MAX_CPUS; to_cpu++) {
+ for (to_cpu = 0; to_cpu < n_cpus; to_cpu++) {
char *fmt = "%-15s %3d:%-3d %'-14.0f %'-11.0f %'-10.2f %s\n";
char *fm2 = "%-15s %3s:%-3d %'-14.0f %'-11.0f %'-10.2f %s\n";
char *errstr = "";
@@ -475,7 +476,7 @@ static void stats_collect(struct stats_record *rec)
map_collect_percpu(fd, 1, &rec->redir_err);

fd = cpumap_enqueue_cnt_map_fd;
- for (i = 0; i < MAX_CPUS; i++)
+ for (i = 0; i < n_cpus; i++)
map_collect_percpu(fd, i, &rec->enq[i]);

fd = cpumap_kthread_cnt_map_fd;
@@ -549,10 +550,10 @@ static int create_cpu_entry(__u32 cpu, __u32 queue_size,
*/
static void mark_cpus_unavailable(void)
{
- __u32 invalid_cpu = MAX_CPUS;
+ __u32 invalid_cpu = n_cpus;
int ret, i;

- for (i = 0; i < MAX_CPUS; i++) {
+ for (i = 0; i < n_cpus; i++) {
ret = bpf_map_update_elem(cpus_available_map_fd, &i,
&invalid_cpu, 0);
if (ret) {
@@ -688,6 +689,8 @@ int main(int argc, char **argv)
int prog_fd;
__u32 qsize;

+ n_cpus = get_nprocs_conf();
+
/* Notice: choosing he queue size is very important with the
* ixgbe driver, because it's driver page recycling trick is
* dependend on pages being returned quickly. The number of
@@ -757,7 +760,7 @@ int main(int argc, char **argv)
case 'c':
/* Add multiple CPUs */
add_cpu = strtoul(optarg, NULL, 0);
- if (add_cpu >= MAX_CPUS) {
+ if (add_cpu >= n_cpus) {
fprintf(stderr,
"--cpu nr too large for cpumap err(%d):%s\n",
errno, strerror(errno));
--
2.25.1