On 5/12/20 3:51 AM, Lorenzo Bianconi wrote:
On 5/11/20 1:24 PM, Lorenzo Bianconi wrote:
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@xxxxxxxxxx>
---
samples/bpf/xdp_redirect_cpu_kern.c | 2 +-
samples/bpf/xdp_redirect_cpu_user.c | 29 ++++++++++++++++-------------
2 files changed, 17 insertions(+), 14 deletions(-)
[...]
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();
get_nprocs() gets the number of available cpus, not including offline cpus.
But gaps may exist in cpus, e.g., get_nprocs() returns 4, and cpus are
0-1,4-5. map updates will miss cpus 4-5. And in this situation,
map_update will fail on offline cpus.
This sample test does not need to deal with complication of
cpu offlining, I think. Maybe we can get
n_cpus = get_nprocs();
n_cpus_conf = get_nprocs_conf();
if (n_cpus != n_cpus_conf) {
/* message that some cpus are offline and not supported. */
return error
}
Hi Yonghong,
thanks for pointing this out. Why not just use:
n_cpus = get_nprocs_conf()
and let the user pick the right cpu id with 'c' option (since it is mandatory)?
Not aware of 'c' option. Yes, get_nprocs_conf() directly works too.
Regards,
Lorenzo
+
/* 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));
