Re: [PATCH v2 2/2] gpu/tests/buddy: Add range-bias pruning and free-order tracking tests

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] gpu/tests/buddy: 64-bit division in gpu_test_buddy_range_bias_pruning()
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commit c218b91af95d861d31913d5c9b3ba0681e319523
Author: Sanjay Yadav <sanjay.kumar.yadav@intel.com>

gpu/tests/buddy: Add range-bias pruning and free-order tracking tests

This commit adds KUnit tests in drivers/gpu/tests/gpu_buddy_test.c to verify
range-bias subtree pruning and subtree_max_free_order tracking across block
allocation, splitting, coalescing, and trimming operations.

> diff --git a/drivers/gpu/tests/gpu_buddy_test.c b/drivers/gpu/tests/gpu_buddy_test.c
> index b75d32ca6ca0a..4c7e823d57892 100644
> --- a/drivers/gpu/tests/gpu_buddy_test.c
> +++ b/drivers/gpu/tests/gpu_buddy_test.c
> @@ -1586,6 +1586,311 @@ static void gpu_test_buddy_addr_to_block(struct kunit *test)
>  	gpu_buddy_fini(&mm);
>  }
>  
[ ... ]
> +static void gpu_test_buddy_range_bias_pruning(struct kunit *test)
> +{
> +	const u64 mm_size = SZ_512M, range_end = SZ_128M, chunk = SZ_4K;
> +	const unsigned int nr = range_end / chunk, window = 1024;
> +	const u64 holes[] = { 0, range_end / 2 + 3 * chunk };
> +	struct gpu_buddy_block *block, *hidden;
> +	u64 first_ns = 0, last_ns = 0;
> +	unsigned int i, misplaced = 0;
> +	LIST_HEAD(allocated);
> +	struct gpu_buddy mm;
> +	LIST_HEAD(tmp);
> +	int err;
[ ... ]
> +	for (i = 0; i < nr; i++) {
> +		ktime_t start = ktime_get();
> +		u64 elapsed;
> +
> +		err = gpu_buddy_alloc_blocks(&mm, 0, range_end, chunk, chunk,
> +					     &allocated, GPU_BUDDY_RANGE_ALLOCATION);
> +		elapsed = ktime_to_ns(ktime_sub(ktime_get(), start));
> +		KUNIT_ASSERT_EQ_MSG(test, err, 0, "range alloc %u failed\n", i);
> +
> +		if (i < window)
> +			first_ns += elapsed;
> +		else if (i >= nr - window)
> +			last_ns += elapsed;
> +
> +		block = list_last_entry(&allocated, struct gpu_buddy_block, link);
> +		if (gpu_buddy_block_offset(block) != range_end - (u64)(i + 1) * chunk)
> +			misplaced++;
> +	}
> +
> +	kunit_info(test, "first %u range allocs: %llu us, last %u: %llu us\n",
> +		   window, first_ns / NSEC_PER_USEC, window, last_ns / NSEC_PER_USEC);

[Severity: Low]
In gpu_test_buddy_range_bias_pruning() in drivers/gpu/tests/gpu_buddy_test.c,
first_ns and last_ns are u64 variables that accumulate runtime nanosecond
durations. On 32-bit architectures with CONFIG_GPU_BUDDY_KUNIT_TEST enabled,
won't dividing them directly with the / operator by NSEC_PER_USEC emit calls
to __udivdi3 or __aeabi_uldivmod and cause a link failure?

Should this use div_u64() (or ktime_to_us()) instead?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/cover.1792599420.git.sanjay.kumar.yadav@intel.com?part=2