Re: [RFC Patch 0/5] Make anon_vma operations testable

[David Hildenbrand <david@redhat.com>]

On 31.05.25 01:23, Wei Yang wrote:
> On Fri, May 30, 2025 at 04:39:21PM +0200, David Hildenbrand wrote:
> [...]
>>>
>>> Here you mean for all anon/shmem/pagecache pages, we could have two category
>>> tests:
>>>
>>>     * migrate and write different data from on process, verify each process see
>>>       new data
>>>     * trigger pageout from one process, verify each process has it pageout
>>>       (/proc/self/pagemap)
>>>
>>> While one of these category is enough, right? Just like KSM below, migrate or
>>> pageout.
>>
>> Both cases will trigger different code paths: for example, migration will
>> trigger restoring of migration entries, which is a different rmap operation
>> not triggered by pageout/pagein :)
>>
>> Pageout is probably easier to implement: but we couldn't test hugetlb. With
>> migration we probably could also test hugetlb rmap code (yet another case we
>> should probably cover).
>>
> 
> Oh, the pageout/pagein here is the madvise(MADV_PAGEOUT) one you mention in
> your previous reply?

Yes, migration (via move_pages(), but requiring two NUMA nodes) vs. 
pageout (via madvise(MADV_PAGEOUT) which would require a similar "force" 
way of succeeding on shared pages).

-- 
Cheers,

David / dhildenb