Shared dirty pages do not need to be flushed under page table lock
for the fullmm case, because there will be no subsequent access
through the TLBs.
---
mm/memory.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 1161ed3f1d0b..490689909186 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1322,8 +1322,18 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
if (!PageAnon(page)) {
if (pte_dirty(ptent)) {
- force_flush = 1;
- locked_flush = 1;
+ /*
+ * Page must be flushed from TLBs
+ * before releasing PTL to synchronize
+ * with page_mkclean and avoid another
+ * thread writing to the page through
+ * the old TLB after it was marked
+ * clean.
+ */
+ if (!tlb->fullmm) {
+ force_flush = 1;
+ locked_flush = 1;
+ }
set_page_dirty(page);
}
if (pte_young(ptent) &&
--
2.17.0
