Re: [LTP] [PATCH] numa_helper: fix compatibility with older libnuma

[Caspar Zhang <caspar@casparzhang.com>]

On 07/12/2012 10:09 PM, Jan Stancek wrote:
> numa_helper relied on functions that do not exist
> in old libnuma (<1), which caused that it couldn't be
> compiled on old distros, for example RHEL 5.3.
>
> Old libnuma and kernel also do not support MPOL_F_MEMS_ALLOWED,
> in which case it will assume that any node with memory > 0 can
> be used.
>
> This patch adds compatibility for older versions, I tested it with:
> numactl-0.9.8-7.el5
> numactl-2.0.3-9.el6
> numactl-2.0.7-6.el7
>
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>   testcases/kernel/syscalls/numa/lib/Makefile      |    2 +-
>   testcases/kernel/syscalls/numa/lib/numa_helper.c |   52 +++++++++++++++++-----
>   2 files changed, 41 insertions(+), 13 deletions(-)
>
> diff --git a/testcases/kernel/syscalls/numa/lib/Makefile b/testcases/kernel/syscalls/numa/lib/Makefile
> index d4a6f41..ba2fb48 100644
> --- a/testcases/kernel/syscalls/numa/lib/Makefile
> +++ b/testcases/kernel/syscalls/numa/lib/Makefile
> @@ -20,7 +20,7 @@ top_srcdir		?= ../../../../..
>
>   include $(top_srcdir)/include/mk/env_pre.mk
>
> -CPPFLAGS		+= -I../../../include
> +CPPFLAGS		+= -I../../../include $(NUMA_CPPFLAGS)
>   LIB			:= libnuma_helper.a
>
>   include $(top_srcdir)/include/mk/lib.mk
> diff --git a/testcases/kernel/syscalls/numa/lib/numa_helper.c b/testcases/kernel/syscalls/numa/lib/numa_helper.c
> index 855ee2c..20b06ca 100644
> --- a/testcases/kernel/syscalls/numa/lib/numa_helper.c
> +++ b/testcases/kernel/syscalls/numa/lib/numa_helper.c
> @@ -53,46 +53,74 @@ int get_allowed_nodes_arr(int *num_allowed_nodes, int **allowed_nodes)
>   {
>   #if HAVE_NUMA_H
>   	int i;
> -	struct bitmask *allowed_nodemask = NULL;
> +	nodemask_t *allowed_nodemask = NULL;
> +	unsigned long max_node;
> +
> +#if !defined(LIBNUMA_API_VERSION) || LIBNUMA_API_VERSION < 2
> +	max_node = NUMA_NUM_NODES;
> +	/*
> +	 * NUMA_NUM_NODES is not reliable, libnuma >=2 is looking
> +	 * at /proc/self/status to figure out correct number.
> +	 * If buffer is not large enough get_mempolicy will fail with EINVAL.
> +	 */
> +	if (max_node < 1024)
> +		max_node = 1024;
> +#else
> +	max_node = numa_max_possible_node() + 1;
>   #endif
> +#endif /* HAVE_NUMA_H */
> +
>   	*num_allowed_nodes = 0;
>   	if (allowed_nodes)
>   		*allowed_nodes = NULL;
>
> -#if HAVE_NUMA_H && HAVE_MPOL_CONSTANTS
> -	if ((allowed_nodemask = numa_allocate_nodemask()) == NULL)
> +#if HAVE_NUMA_H
> +	if ((allowed_nodemask = malloc(max_node/8+1)) == NULL)

Better not use assignment in if condition, you need use:

allowed_nodemask = malloc(max_node/8+1);
if (allowed_nodemask == NULL)
     ....

Else checkpatch.pl will complain.

Rest looks good to me.

Thanks,
Caspar

>   		return -1;
> +	nodemask_zero(allowed_nodemask);
>
>   	if (allowed_nodes) {
> -		*allowed_nodes = malloc(sizeof(int)*allowed_nodemask->size);
> -		if (*allowed_nodes == NULL)
> +		*allowed_nodes = malloc(sizeof(int)*max_node);
> +		if (*allowed_nodes == NULL) {
> +			free(allowed_nodemask);
>   			return -1;
> +		}
>   	}
>
> +#if MPOL_F_MEMS_ALLOWED
>   	/*
>   	 * avoid numa_get_mems_allowed(), because of bug in getpol()
>   	 * utility function in older versions:
>   	 * http://www.spinics.net/lists/linux-numa/msg00849.html
>   	 */
> -	if (syscall(__NR_get_mempolicy, NULL, allowed_nodemask->maskp,
> -		allowed_nodemask->size, 0, MPOL_F_MEMS_ALLOWED) < 0) {
> -		numa_bitmask_free(allowed_nodemask);
> +	if (syscall(__NR_get_mempolicy, NULL, allowed_nodemask->n,
> +		max_node, 0, MPOL_F_MEMS_ALLOWED) < 0) {
> +		free(allowed_nodemask);
>   		if (allowed_nodes) {
>   			free(*allowed_nodes);
>   			*allowed_nodes = NULL;
>   		}
>   		return -2;
>   	}
> +#else
> +	/*
> +	 * old libnuma/kernel don't have MPOL_F_MEMS_ALLOWED, so let's assume
> +	 * that we can use any node with memory > 0
> +	 */
> +	for (i = 0; i < max_node; i++)
> +		if (numa_node_size64(i, NULL) > 0)
> +			nodemask_set(allowed_nodemask, i);
>
> -	for (i = 0; i <	allowed_nodemask->size; i++) {
> -		if (numa_bitmask_isbitset(allowed_nodemask, i)) {
> +#endif /* MPOL_F_MEMS_ALLOWED */
> +	for (i = 0; i < max_node; i++) {
> +		if (nodemask_isset(allowed_nodemask, i)) {
>   			if (allowed_nodes)
>   				(*allowed_nodes)[*num_allowed_nodes] = i;
>   			(*num_allowed_nodes)++;
>   		}
>   	}
> -	numa_bitmask_free(allowed_nodemask);
> -#endif
> +	free(allowed_nodemask);
> +#endif /* HAVE_NUMA_H */
>   	return 0;
>   }
>
>



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