Re: [PATCH] selftest/vm: Fix ksm selftest to run with different NUMA topologies

[Tyler Hicks <tyhicks@linux.microsoft.com>]

On 2021-09-13 18:00:40, Aneesh Kumar K.V wrote:
> Platforms can have non-contiguous NUMA nodes like below
> 
>  #numactl  -H
> available: 2 nodes (0,8)
> .....
> node distances:
> node   0   8
>   0:  10  40
>   8:  40  10
> 
>  #numactl  -H
> available: 1 nodes (1)
> ....
> node distances:
> node   1
>   1:  10
> 
> Hence update the test to not assume the presence of Node 0 and 1
> and also use numa_num_configured_nodes() instead of numa_max_node
> for finding whether to skip the test.
> 

I think this should be added:

 Fixes: 82e717ad3501 ("selftests: vm: add KSM merging across nodes test")

The rest looks good to me:

 Reviewed-by: Tyler Hicks <tyhicks@linux.microsoft.com>

Tyler

> Cc: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
> Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
> Cc: Tyler Hicks <tyhicks@linux.microsoft.com>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Shuah Khan <shuah@kernel.org>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
>  tools/testing/selftests/vm/ksm_tests.c | 32 +++++++++++++++++++++++---
>  1 file changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c
> index b61dcdb44c5b..5bdfc5fe4d57 100644
> --- a/tools/testing/selftests/vm/ksm_tests.c
> +++ b/tools/testing/selftests/vm/ksm_tests.c
> @@ -354,12 +354,37 @@ static int check_ksm_zero_page_merge(int mapping, int prot, long page_count, int
>  	return KSFT_FAIL;
>  }
>  
> +static unsigned long get_next_mem_node(unsigned long node)
> +{
> +
> +	long node_size;
> +	unsigned long i;
> +	unsigned long max_node = numa_max_node();
> +	/*
> +	 * start from node and find the next memory node
> +	 */
> +restart:
> +	for (i = node + 1; i <= max_node; i++) {
> +		node_size = numa_node_size(i, NULL);
> +		if (node_size > 0)
> +			return i;
> +	}
> +	node = -1;
> +	goto restart;
> +}
> +
> +static unsigned long get_first_mem_node(void)
> +{
> +	return get_next_mem_node(-1);
> +}
> +
>  static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_across_nodes,
>  				size_t page_size)
>  {
>  	void *numa1_map_ptr, *numa2_map_ptr;
>  	struct timespec start_time;
>  	int page_count = 2;
> +	unsigned long first_node;
>  
>  	if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) {
>  		perror("clock_gettime");
> @@ -370,7 +395,7 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
>  		perror("NUMA support not enabled");
>  		return KSFT_SKIP;
>  	}
> -	if (numa_max_node() < 1) {
> +	if (numa_num_configured_nodes() <= 1) {
>  		printf("At least 2 NUMA nodes must be available\n");
>  		return KSFT_SKIP;
>  	}
> @@ -378,8 +403,9 @@ static int check_ksm_numa_merge(int mapping, int prot, int timeout, bool merge_a
>  		return KSFT_FAIL;
>  
>  	/* allocate 2 pages in 2 different NUMA nodes and fill them with the same data */
> -	numa1_map_ptr = numa_alloc_onnode(page_size, 0);
> -	numa2_map_ptr = numa_alloc_onnode(page_size, 1);
> +	first_node = get_first_mem_node();
> +	numa1_map_ptr = numa_alloc_onnode(page_size, first_node);
> +	numa2_map_ptr = numa_alloc_onnode(page_size, get_next_mem_node(first_node));
>  	if (!numa1_map_ptr || !numa2_map_ptr) {
>  		perror("numa_alloc_onnode");
>  		return KSFT_FAIL;
> -- 
> 2.31.1
>