mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios

A large folio which is smaller than a PMD does not need to do the extra
work in try_to_unmap() of trying to split a PMD entry.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2020-08-15 19:28:51 -04:00
parent 820c4e2e6f
commit 343b288834

View File

@ -1765,7 +1765,8 @@ retry:
enum ttu_flags flags = TTU_BATCH_FLUSH;
bool was_swapbacked = PageSwapBacked(page);
if (unlikely(PageTransHuge(page)))
if (PageTransHuge(page) &&
thp_order(page) >= HPAGE_PMD_ORDER)
flags |= TTU_SPLIT_HUGE_PMD;
try_to_unmap(folio, flags);