Re: [PATCH v5 2/2] selftests/mm: add PAGEMAP_SCAN test for THP PMD holes

["David Hildenbrand (Arm)" <david@kernel.org>]

On 7/16/26 15:03, Kiryl Shutsemau wrote:
> On Thu, Jul 16, 2026 at 01:25:22PM +0200, David Hildenbrand (Arm) wrote:
>>
>>> +	/* Fast path: category_mask == return_mask == PAGE_IS_WRITTEN. */
>>> +	ret = pagemap_ioctl(mem, hpage_size, regions, ARRAY_SIZE(regions), 0, 0,
>>> +			    PAGE_IS_WRITTEN, 0, 0, PAGE_IS_WRITTEN);
>>> +	for (i = 0; ret > 0 && i < ret; i++)
>>> +		fast += LEN(regions[i]);
>>> +
>>> +	/* Generic path: same query expressed via category_anyof_mask. */
>>> +	ret = pagemap_ioctl(mem, hpage_size, regions, ARRAY_SIZE(regions), 0, 0,
>>> +			    0, PAGE_IS_WRITTEN, 0, PAGE_IS_WRITTEN);
>>> +	for (i = 0; ret > 0 && i < ret; i++)
>>> +		slow += LEN(regions[i]);
>>> +
>>> +	ksft_test_result(fast == npages && slow == npages,
>>> +			 "%s pmd-hole reported written by both paths (%ld, %ld of %d)\n",
>>> +			 __func__, fast, slow, npages);
>>> +out:
>>> +	wp_free(mem, hpage_size);
>>> +	munmap(area, 2 * hpage_size);
>>> +}
>>
>> Sorry if I wasn't clear. I think unpopulated_thp_scan_test() can actually reuse
>> bits of unpopulated_scan_test().
> 
> Ah. Make sense.
> 
> Here's my take on this. Looks good?

Yes, thanks!

-- 
Cheers,

David