Re: [dpdk-dev] [PATCH] mem: fix allocation failure on non-NUMA kernel

[Nicolas Dichtel <nicolas.dichtel@6wind.com>]

Le 05/08/2020 à 14:26, Nick Connolly a écrit :
> Running dpdk-helloworld on Linux with lib numa present,
> but no kernel support for NUMA (CONFIG_NUMA=n) causes
> ret_service_init() to fail with EAL: error allocating
> rte services array.
> 
> alloc_seg() calls get_mempolicy to verify that the allocation
> has happened on the correct socket, but receives ENOSYS from
> the kernel and fails the allocation.
> 
> The allocated socket should only be verified if check_numa() is true.
> 
> Fixes: 2a96c88be83e ("mem: ease init in a docker container")
I'm wondering if the bug existed before this commit.

Before this commit, it was:
       move_pages(getpid(), 1, &addr, NULL, &cur_socket_id, 0);
       if (cur_socket_id != socket_id) {
               /* error */

Isn't it possible to hit this error case if CONFIG_NUMA is unset in the kernel?

[snip]
> +	if (check_numa()) {
> +		ret = get_mempolicy(&cur_socket_id, NULL, 0, addr,
> +					MPOL_F_NODE | MPOL_F_ADDR);
> +		if (ret < 0) {
> +			RTE_LOG(DEBUG, EAL, "%s(): get_mempolicy: %s\n",
> +				__func__, strerror(errno));
> +			goto mapped;
> +		} else if (cur_socket_id != socket_id) {
> +			RTE_LOG(DEBUG, EAL,
> +					"%s(): allocation happened on wrong socket (wanted %d, got %d)\n",
> +				__func__, socket_id, cur_socket_id);
> +			goto mapped;
> +		}
> +	} else {
> +		if (rte_socket_count() > 1)
> +			RTE_LOG(DEBUG, EAL, "%s(): not checking socket for allocation (wanted %d)\n",
> +					__func__, socket_id);
nit: maybe an higher log level like WARNING?


Regards,
Nicolas