[PATCH] drm/mm: add ig_frag selftest

[Christian König]

Am 28.05.20 um 15:05 schrieb Nirmoy Das:
> This patch introduces fragmentation in the address range
> and measures time taken by 10k insertions for each modes.
>
> ig_frag() will fail if one of the mode takes more than 1 sec.
>
> Output:
> <snip>
> [   37.326723] drm_mm: igt_sanitycheck - ok!
> [   37.326727] igt_debug 0x0000000000000000-0x0000000000000200: 512: free
> [   37.326728] igt_debug 0x0000000000000200-0x0000000000000600: 1024: used
> [   37.326728] igt_debug 0x0000000000000600-0x0000000000000a00: 1024: free
> [   37.326729] igt_debug 0x0000000000000a00-0x0000000000000e00: 1024: used
> [   37.326730] igt_debug 0x0000000000000e00-0x0000000000001000: 512: free
> [   37.326730] igt_debug total: 4096, used 2048 free 2048
> [   56.040064] drm_mm: best fragmented insert took 504 msecs
> [   56.082184] drm_mm: bottom-up fragmented insert took 40 msecs
> [   56.102255] drm_mm: top-down fragmented insert took 20 msecs
> [   56.107177] drm_mm: evict fragmented insert took 4 msecs
> <snip>
>
> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>

Off hand that looks like it should work, but I'm really not an expert 
for the drm_mm code.

Feel free to add an Acked-by: Christian König 
<christian.koenig at amd.com>, but I would consider doing what Chris said 
as well.

Christian.

> ---
>   drivers/gpu/drm/selftests/drm_mm_selftests.h |  1 +
>   drivers/gpu/drm/selftests/test-drm_mm.c      | 59 ++++++++++++++++++++
>   2 files changed, 60 insertions(+)
>
> diff --git a/drivers/gpu/drm/selftests/drm_mm_selftests.h b/drivers/gpu/drm/selftests/drm_mm_selftests.h
> index 6b943ea1c57d..8c87c964176b 100644
> --- a/drivers/gpu/drm/selftests/drm_mm_selftests.h
> +++ b/drivers/gpu/drm/selftests/drm_mm_selftests.h
> @@ -14,6 +14,7 @@ selftest(insert, igt_insert)
>   selftest(replace, igt_replace)
>   selftest(insert_range, igt_insert_range)
>   selftest(align, igt_align)
> +selftest(frag, igt_frag)
>   selftest(align32, igt_align32)
>   selftest(align64, igt_align64)
>   selftest(evict, igt_evict)
> diff --git a/drivers/gpu/drm/selftests/test-drm_mm.c b/drivers/gpu/drm/selftests/test-drm_mm.c
> index 9aabe82dcd3a..4c08ca86bb86 100644
> --- a/drivers/gpu/drm/selftests/test-drm_mm.c
> +++ b/drivers/gpu/drm/selftests/test-drm_mm.c
> @@ -1033,6 +1033,65 @@ static int igt_insert_range(void *ignored)
>   	return 0;
>   }
>   
> +static int igt_frag(void *ignored)
> +{
> +	const struct insert_mode *mode;
> +	struct drm_mm mm;
> +	struct drm_mm_node *nodes, *node, *next;
> +	unsigned int size = 4096, align = 8192;
> +	unsigned long start, timeout = 1000;
> +	const unsigned int max_count = 10000;
> +	unsigned int i;
> +	int ret = -EINVAL;
> +
> +	/* For each of the possible insertion modes, we pass an size, alignment
> +	 * value that is known to introduce fragmentation and check that it
> +	 * doesn't take more than 1 sec.
> +	 */
> +
> +	nodes = vzalloc(array_size(max_count, sizeof(*nodes)));
> +	if (!nodes)
> +		goto err;
> +
> +	drm_mm_init(&mm, 1, U64_MAX - 2);
> +
> +	for (mode = insert_modes; mode->name; mode++) {
> +		start = jiffies;
> +
> +		for (i = 0; i < max_count; i++) {
> +			if (jiffies_to_msecs(jiffies - start) >= timeout) {
> +				pr_err("%s fragmented insert took more than %lu msecs\n",
> +				       mode->name, timeout);
> +				goto out;
> +			}
> +
> +			if (!expect_insert(&mm, &nodes[i],
> +					   size, align, i, mode)) {
> +				pr_err("%s insert failed with alignment=%d",
> +				       mode->name, align);
> +				goto out;
> +			}
> +		}
> +
> +		pr_info("%s fragmented insert took %d msecs\n",
> +			mode->name, jiffies_to_msecs(jiffies - start));
> +		drm_mm_for_each_node_safe(node, next, &mm)
> +			drm_mm_remove_node(node);
> +		DRM_MM_BUG_ON(!drm_mm_clean(&mm));
> +
> +		cond_resched();
> +	}
> +
> +	ret = 0;
> +out:
> +	drm_mm_for_each_node_safe(node, next, &mm)
> +		drm_mm_remove_node(node);
> +	drm_mm_takedown(&mm);
> +	vfree(nodes);
> +err:
> +	return ret;
> +}
> +
>   static int igt_align(void *ignored)
>   {
>   	const struct insert_mode *mode;