On Tuesday, 2 March 2021 3:10:49 AM AEDT Jason Gunthorpe wrote:

quoted

+       while (page_vma_mapped_walk(&pvmw)) {
+               /*
+                * If the page is mlock()d, we cannot swap it out.
+                * If it's recently referenced (perhaps page_referenced
+                * skipped over this mm) then we should reactivate it.
+                */
+               if (vma->vm_flags & VM_LOCKED) {

And since we write the data without holding the PTLs this looks
pointless, unless there is some other VM_LOCKED manipulation

Thanks. I couldn't find any other manipulation of VM_LOCKED whilst holding the 
PTL so I'll remove this redundant check.

 - Alistair