On Fri, Aug 22, 2014 at 12:51:47AM +0300, Kirill A. Shutemov wrote: > > > One thing: there could be (I haven't checked) complications on > > > vma_merge(): since vm_flags are identical it assumes that it can reuse > > > vma->vm_page_prot of expanded vma. But VM_SOFTDIRTY is excluded from > > > vm_flags compatibility check. What should we do with vm_page_prot there? > > > > Since the merged VMA will have VM_SOFTDIRTY set, it's OK that it's vm_page_prot > > won't be setup for write notifications. For the purpose of process migration, > > you'll just get some false positives, which is tolerable. > > Right. But should we disable writenotify back to avoid exessive wp-faults > if it was enabled due to soft-dirty (the case when expanded vma is > soft-dirty)? Ah, I understand now. I've got a patch in the works that disables the write faults when a VMA is merged. I'll send a series with all of the changes tomorrow. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>