On Wed, Oct 27, 2021 at 1:50 PM Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote:
>
> On Wed, Oct 27, 2021 at 12:52:21PM -0700, Yang Shi wrote:
> > +++ b/mm/khugepaged.c
> > @@ -445,22 +445,25 @@ static bool hugepage_vma_check(struct vm_area_struct *vma,
> > if (!transhuge_vma_enabled(vma, vm_flags))
> > return false;
> >
> > - /* Enabled via shmem mount options or sysfs settings. */
> > - if (shmem_file(vma->vm_file) && shmem_huge_enabled(vma)) {
> > + if (vma->vm_file)
> > return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
> > HPAGE_PMD_NR);
> > - }
> > +
> > + /* Enabled via shmem mount options or sysfs settings. */
> > + if (shmem_file(vma->vm_file))
> > + return shmem_huge_enabled(vma);
>
> This doesn't make sense to me. if vma->vm_file, we already returned,
> so this is dead code.
Yes, Song mentioned the same thing. Fixed by an incremental patch.
>
> > /* THP settings require madvise. */
> > if (!(vm_flags & VM_HUGEPAGE) && !khugepaged_always())
> > return false;
> >
> > - /* Read-only file mappings need to be aligned for THP to work. */
> > + /* Only regular file is valid */
> > if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && vma->vm_file &&
> > - !inode_is_open_for_write(vma->vm_file->f_inode) &&
> > (vm_flags & VM_EXEC)) {
> > - return IS_ALIGNED((vma->vm_start >> PAGE_SHIFT) - vma->vm_pgoff,
> > - HPAGE_PMD_NR);
> > + struct inode *inode = vma->vm_file->f_inode;
> > +
> > + return !inode_is_open_for_write(inode) &&
> > + S_ISREG(inode->i_mode);
> > }
> >
> > if (!vma->anon_vma || vma->vm_ops)
> > --
> > 2.26.2
> >
