parisc,metag: Do not hardcode maximum userspace stack size

[deliverable/linux.git] / mm / rmap.c

diff --git a/mm/rmap.c b/mm/rmap.c
index 8fc049f9a5a6c5d511ac7a5ac0dd41c698ed99a3..9c3e77396d1a118edb8f2de7d16ff835ed214f0a 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1165,6 +1165,16 @@ int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
                }
                set_pte_at(mm, address, pte,
                           swp_entry_to_pte(make_hwpoison_entry(page)));
+       } else if (pte_unused(pteval)) {
+               /*
+                * The guest indicated that the page content is of no
+                * interest anymore. Simply discard the pte, vmscan
+                * will take care of the rest.
+                */
+               if (PageAnon(page))
+                       dec_mm_counter(mm, MM_ANONPAGES);
+               else
+                       dec_mm_counter(mm, MM_FILEPAGES);
        } else if (PageAnon(page)) {
                swp_entry_t entry = { .val = page_private(page) };
                pte_t swp_pte;
@@ -1322,9 +1332,19 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
                BUG_ON(!page || PageAnon(page));
 
                if (locked_vma) {
-                       mlock_vma_page(page);   /* no-op if already mlocked */
-                       if (page == check_page)
+                       if (page == check_page) {
+                               /* we know we have check_page locked */
+                               mlock_vma_page(page);
                                ret = SWAP_MLOCK;
+                       } else if (trylock_page(page)) {
+                               /*
+                                * If we can lock the page, perform mlock.
+                                * Otherwise leave the page alone, it will be
+                                * eventually encountered again later.
+                                */
+                               mlock_vma_page(page);
+                               unlock_page(page);
+                       }
                        continue;       /* don't unmap */
                }