[PATCH 2/2] drm/tests/drm_buddy: add alloc_contiguous test

[Matthew Auld]

On 13/02/2024 13:52, Arunpravin Paneer Selvam wrote:
> Sanity check DRM_BUDDY_CONTIGUOUS_ALLOCATION.
> 
> References: https://gitlab.freedesktop.org/drm/amd/-/issues/3097
> Signed-off-by: Matthew Auld <matthew.auld at intel.com>
> Reviewed-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>

It looks like you changed the patch authorship here.

> Cc: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> Cc: Limonciello <mario.limonciello at amd.com>
> Cc: Christian König <christian.koenig at amd.com>
> Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam at amd.com>
> ---
>   drivers/gpu/drm/tests/drm_buddy_test.c | 89 ++++++++++++++++++++++++++
>   1 file changed, 89 insertions(+)
> 
> diff --git a/drivers/gpu/drm/tests/drm_buddy_test.c b/drivers/gpu/drm/tests/drm_buddy_test.c
> index ea2af6bd9abe..fee6bec757d1 100644
> --- a/drivers/gpu/drm/tests/drm_buddy_test.c
> +++ b/drivers/gpu/drm/tests/drm_buddy_test.c
> @@ -8,6 +8,7 @@
>   
>   #include <linux/prime_numbers.h>
>   #include <linux/sched/signal.h>
> +#include <linux/sizes.h>
>   
>   #include <drm/drm_buddy.h>
>   
> @@ -18,6 +19,93 @@ static inline u64 get_size(int order, u64 chunk_size)
>   	return (1 << order) * chunk_size;
>   }
>   
> +static void drm_test_buddy_alloc_contiguous(struct kunit *test)
> +{
> +	u64 mm_size, ps = SZ_4K, i, n_pages, total;
> +	struct drm_buddy_block *block;
> +	struct drm_buddy mm;
> +	LIST_HEAD(left);
> +	LIST_HEAD(middle);
> +	LIST_HEAD(right);
> +	LIST_HEAD(allocated);
> +
> +	mm_size = 16 * 3 * SZ_4K;
> +
> +	KUNIT_EXPECT_FALSE(test, drm_buddy_init(&mm, mm_size, ps));
> +
> +	/*
> +	 * Idea is to fragment the address space by alternating block
> +	 * allocations between three different lists; one for left, middle and
> +	 * right. We can then free a list to simulate fragmentation. In
> +	 * particular we want to exercise the DRM_BUDDY_CONTIGUOUS_ALLOCATION,
> +	 * including the try_harder path.
> +	 */
> +
> +	i = 0;
> +	n_pages = mm_size / ps;
> +	do {
> +		struct list_head *list;
> +		int slot = i % 3;
> +
> +		if (slot == 0)
> +			list = &left;
> +		else if (slot == 1)
> +			list = &middle;
> +		else
> +			list = &right;
> +		KUNIT_ASSERT_FALSE_MSG(test,
> +				       drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							      ps, ps, list, 0),
> +				       "buddy_alloc hit an error size=%d\n",
> +				       ps);
> +	} while (++i < n_pages);
> +
> +	KUNIT_ASSERT_TRUE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							   3 * ps, ps, &allocated,
> +							   DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc didn't error size=%d\n", 3 * ps);
> +
> +	drm_buddy_free_list(&mm, &middle);
> +	KUNIT_ASSERT_TRUE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							   3 * ps, ps, &allocated,
> +							   DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc didn't error size=%llu\n", 3 * ps);
> +	KUNIT_ASSERT_TRUE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							   2 * ps, ps, &allocated,
> +							   DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc didn't error size=%llu\n", 2 * ps);
> +
> +	drm_buddy_free_list(&mm, &right);
> +	KUNIT_ASSERT_TRUE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							   3 * ps, ps, &allocated,
> +							   DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc didn't error size=%llu\n", 3 * ps);
> +	/*
> +	 * At this point we should have enough contiguous space for 2 blocks,
> +	 * however they are never buddies (since we freed middle and right) so
> +	 * will require the try_harder logic to find them.
> +	 */
> +	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							    2 * ps, ps, &allocated,
> +							    DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc hit an error size=%d\n", 2 * ps);
> +
> +	drm_buddy_free_list(&mm, &left);
> +	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
> +							    3 * ps, ps, &allocated,
> +							    DRM_BUDDY_CONTIGUOUS_ALLOCATION),
> +			       "buddy_alloc hit an error size=%d\n", 3 * ps);
> +
> +	total = 0;
> +	list_for_each_entry(block, &allocated, link)
> +		total += drm_buddy_block_size(&mm, block);
> +
> +	KUNIT_ASSERT_EQ(test, total, ps * 2 + ps * 3);
> +
> +	drm_buddy_free_list(&mm, &allocated);
> +	drm_buddy_fini(&mm);
> +}
> +
>   static void drm_test_buddy_alloc_pathological(struct kunit *test)
>   {
>   	u64 mm_size, size, start = 0;
> @@ -280,6 +368,7 @@ static struct kunit_case drm_buddy_tests[] = {
>   	KUNIT_CASE(drm_test_buddy_alloc_optimistic),
>   	KUNIT_CASE(drm_test_buddy_alloc_pessimistic),
>   	KUNIT_CASE(drm_test_buddy_alloc_pathological),
> +	KUNIT_CASE(drm_test_buddy_alloc_contiguous),
>   	{}
>   };
>