Re: [PATCH RESEND 6/9] selftests/mm: mremap_test: replace random data with deterministic pattern

[Sarthak Sharma]

On 10/1/26 5:30 PM, David Hildenbrand (Arm) wrote:
> On 9/24/26 07:00, Sarthak Sharma wrote:
>> mremap_test uses a random data stream to detect corruption after remap
>> operations. This requires seed handling and byte by byte validation,
>> which is inefficient.
>>
>> Replace it with a deterministic pattern where every word in a page
>> contains its one-based page index. Use memcpy() and memcmp() to
>> initialize and validate the mappings. Remove the pattern seed and
>> its command line option. Also update the comment diagrams to
>> reflect the new deterministic pattern.
>>
>> Suggested-by: David Hildenbrand (Arm) <david@xxxxxxxxxx>
>> Signed-off-by: Sarthak Sharma <sarthak.sharma@xxxxxxx>
>> ---
> 
> How will this patch change with the change in threshold handling? Does it make
> sense to reshuffle the patches?

>From an intermediate patch POV, both ways of doing should be identical:

a) Remove threshold first, then remove randomization:
	i) Adjust random buffer size according to what the test requires
	   and implement the start, mid end pages checking
	ii) Replace rand approach with fixed pattern

b) Remove randomization first, then remove threshold:
	i) Adjust fixed pattern size according to threshold
	ii) Implement the new logic of start, mid and end pages checking
	    and adjust pattern size

But if we plan to remove perf and timing infrastructure before (which I
plan to do in v2), yes removing threshold first would be neater, since
it will keep both the removal patches together. Please let me know if I
am missing something.