On 12.06.25 17:46, Zi Yan wrote:
On 11 Jun 2025, at 23:54, Baolin Wang wrote:
When running the khugepaged selftest for shmem (./khugepaged all:shmem),
I encountered the following test failures:
"
Run test: collapse_full (khugepaged:shmem)
Collapse multiple fully populated PTE table.... Fail
...
Run test: collapse_single_pte_entry (khugepaged:shmem)
Collapse PTE table with single PTE entry present.... Fail
...
Run test: collapse_full_of_compound (khugepaged:shmem)
Allocate huge page... OK
Split huge page leaving single PTE page table full of compound pages... OK
Collapse PTE table full of compound pages.... Fail
"
The reason for the failure is that, it will set MADV_NOHUGEPAGE to prevent
khugepaged from continuing to scan shmem VMA after khugepaged finishes
scanning in the wait_for_scan() function. Moreover, shmem requires a refault
to establish PMD mappings.
However, after commit 2b0f922323cc, PMD mappings are prevented if the VMA is
Can you add the title of the commit? It is easier to understand the context.
2b0f922323cc ("mm: don't install PMD mappings when THPs are disabled by the
hw/process/vma")
Probably checkpatch.pl would point out the same :)
--
Cheers,
David / dhildenb
