On 10/28/22 12:13, Peter Xu wrote:
On Fri, Oct 28, 2022 at 08:23:25AM -0700, Mike Kravetz wrote:
On 10/26/22 21:12, Peter Xu wrote:
On Wed, Oct 26, 2022 at 04:54:01PM -0700, Mike Kravetz wrote:
On 10/26/22 17:42, Peter Xu wrote:
diff --git a/mm/madvise.c b/mm/madvise.c index c7105ec6d08c..d8b4d7e56939 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -790,7 +790,10 @@ static int madvise_free_single_vma(struct vm_area_struct *vma, static long madvise_dontneed_single_vma(struct vm_area_struct *vma, unsigned long start, unsigned long end) {
- zap_page_range(vma, start, end - start);
- if (!is_vm_hugetlb_page(vma))
zap_page_range(vma, start, end - start);- else
clear_hugetlb_page_range(vma, start, end);With the new ZAP_FLAG_UNMAP flag, clear_hugetlb_page_range() can be dropped completely? As zap_page_range() won't be with ZAP_FLAG_UNMAP so we can identify things?
IIUC that's the major reason why I thought the zap flag could be helpful..
Argh. I went to drop clear_hugetlb_page_range() but there is one issue. In zap_page_range() the MMU_NOTIFY_CLEAR notifier is certainly called. However, we really need to have a 'adjust_range_if_pmd_sharing_possible' call in there because the 'range' may be part of a shared pmd. :(
I think we need to either have a separate routine like clear_hugetlb_page_range that sets up the appropriate range, or special case hugetlb in zap_page_range. What do you think? I think clear_hugetlb_page_range is the least bad of the two options.