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

["Yadav, Sanjay Kumar" <sanjay.kumar.yadav@intel.com>]

On 21-10-2026 22:54, sashiko-bot@kernel.org wrote:
> 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()
> --
>
> 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?
Yes, this matches the kernel test robot’s __aeabi_uldivmod failure on 
32-bit ARM.
I reproduced it locally on 32bit compiler and confirmed that replacing 
the direct u64 divisions with div_u64() fixes the issue.
>
> [ ... ]
>