Re: [PATCH 6.6.y] mm: huge_memory: add vma_thp_disabled() and thp_disabled_by_hw()

Hi David,

On Tue, Oct 22, 2024 at 11:07:55AM +0200, David Hildenbrand wrote:

diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9aea11b1477c..dfd6577225d8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -78,19 +78,8 @@ bool hugepage_vma_check(struct vm_area_struct *vma, unsigned long vm_flags, if (!vma->vm_mm) /* vdso */ return false;

• /*

• * Explicitly disabled through madvise or prctl, or some
  

• * architectures may disable THP for some mappings, for
  

• * example, s390 kvm.
  

• * */
  

• if ((vm_flags & VM_NOHUGEPAGE) ||

•    test_bit(MMF_DISABLE_THP, &vma->vm_mm->flags))
  

• return false;
  

• /*

• * If the hardware/firmware marked hugepage support disabled.
  

• */
  

• if (transparent_hugepage_flags & (1 << TRANSPARENT_HUGEPAGE_UNSUPPORTED))

• return false;
  

• if (thp_disabled_by_hw() || vma_thp_disabled(vma, vm_flags))

• return 0;
  

Shouldn't this return false for consistency with the rest of the function?

/* khugepaged doesn't collapse DAX vma, but page fault is fine. */ if (vma_is_dax(vma)) -- 2.46.1

Petr