Re: [PATCH v6] drm/tests/gpu_buddy: add a new test case for buffer clearance during resume

On Tue, 21 Jul 2026, Arunpravin Paneer Selvam <[email protected]> wrote:
> Add a new unit test case for buffer clearance issue during
> resume.
>
> Using a non-power-of-two mm size, allocate alternating blocks of
> 4KiB in an even sequence and free them as cleared. All alternate
> blocks should be marked as dirty and the split blocks should be
> merged back to their original size when the blocks clear reset
> function is called.
>
> Signed-off-by: Arunpravin Paneer Selvam <[email protected]>
> Reviewed-by: Matthew Auld <[email protected]>
> ---
> v6: Standalone repost of patch 3/3 from series 151686; the other two
>     patches are already applied. Rebased onto the gpu_buddy rename
>     (drm_buddy_test.c -> gpu_buddy_test.c, drm_buddy_* -> gpu_buddy_*)
>     and updated the subject accordingly. No functional change; kept
>     Matthew's Reviewed-by as the port is mechanical.
>
>  drivers/gpu/tests/gpu_buddy_test.c | 41 ++++++++++++++++++++++++++++++
>  1 file changed, 41 insertions(+)
>
> diff --git a/drivers/gpu/tests/gpu_buddy_test.c b/drivers/gpu/tests/gpu_buddy_test.c
> index 7df5c2ae83bb..89698563c61b 100644
> --- a/drivers/gpu/tests/gpu_buddy_test.c
> +++ b/drivers/gpu/tests/gpu_buddy_test.c
> @@ -1002,6 +1002,47 @@ static void gpu_test_buddy_alloc_clear(struct kunit *test)
>  				"buddy_alloc hit an error size=%lu\n", ps);
>  	gpu_buddy_free_list(&mm, &allocated, GPU_BUDDY_CLEARED);
>  	gpu_buddy_fini(&mm);
> +
> +	/*
> +	 * Using a non-power-of-two mm size, allocate alternating blocks of 4KiB in an
> +	 * even sequence and free them as cleared. All blocks should be marked as
> +	 * dirty and the split blocks should be merged back to their original
> +	 * size when the blocks clear reset function is called.
> +	 */
> +	KUNIT_EXPECT_FALSE(test, gpu_buddy_init(&mm, mm_size, ps));
> +	KUNIT_EXPECT_EQ(test, mm.max_order, max_order);
> +
> +	i = 0;
> +	n_pages = mm_size / ps;
> +	do {
> +		if (i % 2 == 0)
> +			KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_alloc_blocks(&mm, 0, mm_size,
> +									    ps, ps, &allocated, 0),
> +					"buddy_alloc hit an error size=%lu\n", ps);
> +	} while (++i < n_pages);

Please prefer a for loop over do-while or while. This is so much more
obvious:

	for (i = 0; i < n_pages; i++)

> +
> +	gpu_buddy_free_list(&mm, &allocated, GPU_BUDDY_CLEARED);
> +	gpu_buddy_reset_clear(&mm, false);
> +	KUNIT_EXPECT_EQ(test, mm.clear_avail, 0);
> +
> +	/*
> +	 * Using a non-power-of-two mm size, allocate alternating blocks of 4KiB in an
> +	 * odd sequence and free them as cleared. All blocks should be marked as
> +	 * cleared and the split blocks should be merged back to their original
> +	 * size when the blocks clear reset function is called.
> +	 */
> +	i = 0;
> +	do {
> +		if (i % 2 != 0)
> +			KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_alloc_blocks(&mm, 0, mm_size,
> +									    ps, ps, &allocated, 0),
> +					"buddy_alloc hit an error size=%lu\n", ps);
> +	} while (++i < n_pages);
> +
> +	gpu_buddy_free_list(&mm, &allocated, GPU_BUDDY_CLEARED);
> +	gpu_buddy_reset_clear(&mm, true);
> +	KUNIT_EXPECT_EQ(test, mm.clear_avail, mm_size);
> +	gpu_buddy_fini(&mm);
>  }
>  
>  static void gpu_test_buddy_alloc_contiguous(struct kunit *test)

-- 
Jani Nikula, Intel