On 22.11.23 17:29, Ryan Roberts wrote:
In preparation for supporting anonymous small-sized THP, improve
folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
passed to it. In this case, all contained pages are accounted using the
order-0 folio (or base page) scheme.
Reviewed-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Reviewed-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
---
mm/rmap.c | 28 ++++++++++++++++++++--------
1 file changed, 20 insertions(+), 8 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 49e4d86a4f70..b086dc957b0c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1305,32 +1305,44 @@ void page_add_anon_rmap(struct page *page, struct vm_area_struct *vma,
* This means the inc-and-test can be bypassed.
* The folio does not have to be locked.
*
- * If the folio is large, it is accounted as a THP. As the folio
+ * If the folio is pmd-mappable, it is accounted as a THP. As the folio
* is new, it's assumed to be mapped exclusively by a single process.
*/
void folio_add_new_anon_rmap(struct folio *folio, struct vm_area_struct *vma,
unsigned long address)
{
- int nr;
+ int nr = folio_nr_pages(folio);
- VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma);
+ VM_BUG_ON_VMA(address < vma->vm_start ||
+ address + (nr << PAGE_SHIFT) > vma->vm_end, vma);
__folio_set_swapbacked(folio);
+ __folio_set_anon(folio, vma, address, true);
Likely the changed order doesn't matter.
LGTM
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Cheers,
David / dhildenb
