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-rw-r--r--mm/vmscan.c95
1 files changed, 52 insertions, 43 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 1638814c7848..6fbf707c0ce2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -536,7 +536,9 @@ static inline int is_page_cache_freeable(struct page *page)
* that isolated the page, the page cache radix tree and
* optional buffer heads at page->private.
*/
- return page_count(page) - page_has_private(page) == 2;
+ int radix_pins = PageTransHuge(page) && PageSwapCache(page) ?
+ HPAGE_PMD_NR : 1;
+ return page_count(page) - page_has_private(page) == 1 + radix_pins;
}
static int may_write_to_inode(struct inode *inode, struct scan_control *sc)
@@ -666,6 +668,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
bool reclaimed)
{
unsigned long flags;
+ int refcount;
BUG_ON(!PageLocked(page));
BUG_ON(mapping != page_mapping(page));
@@ -696,11 +699,15 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
* Note that if SetPageDirty is always performed via set_page_dirty,
* and thus under tree_lock, then this ordering is not required.
*/
- if (!page_ref_freeze(page, 2))
+ if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
+ refcount = 1 + HPAGE_PMD_NR;
+ else
+ refcount = 2;
+ if (!page_ref_freeze(page, refcount))
goto cannot_free;
/* note: atomic_cmpxchg in page_freeze_refs provides the smp_rmb */
if (unlikely(PageDirty(page))) {
- page_ref_unfreeze(page, 2);
+ page_ref_unfreeze(page, refcount);
goto cannot_free;
}
@@ -1122,58 +1129,56 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* Try to allocate it some swap space here.
* Lazyfree page could be freed directly
*/
- if (PageAnon(page) && PageSwapBacked(page) &&
- !PageSwapCache(page)) {
- if (!(sc->gfp_mask & __GFP_IO))
- goto keep_locked;
- if (PageTransHuge(page)) {
- /* cannot split THP, skip it */
- if (!can_split_huge_page(page, NULL))
- goto activate_locked;
- /*
- * Split pages without a PMD map right
- * away. Chances are some or all of the
- * tail pages can be freed without IO.
- */
- if (!compound_mapcount(page) &&
- split_huge_page_to_list(page, page_list))
- goto activate_locked;
- }
- if (!add_to_swap(page)) {
- if (!PageTransHuge(page))
- goto activate_locked;
- /* Split THP and swap individual base pages */
- if (split_huge_page_to_list(page, page_list))
- goto activate_locked;
- if (!add_to_swap(page))
- goto activate_locked;
- }
-
- /* XXX: We don't support THP writes */
- if (PageTransHuge(page) &&
- split_huge_page_to_list(page, page_list)) {
- delete_from_swap_cache(page);
- goto activate_locked;
- }
+ if (PageAnon(page) && PageSwapBacked(page)) {
+ if (!PageSwapCache(page)) {
+ if (!(sc->gfp_mask & __GFP_IO))
+ goto keep_locked;
+ if (PageTransHuge(page)) {
+ /* cannot split THP, skip it */
+ if (!can_split_huge_page(page, NULL))
+ goto activate_locked;
+ /*
+ * Split pages without a PMD map right
+ * away. Chances are some or all of the
+ * tail pages can be freed without IO.
+ */
+ if (!compound_mapcount(page) &&
+ split_huge_page_to_list(page,
+ page_list))
+ goto activate_locked;
+ }
+ if (!add_to_swap(page)) {
+ if (!PageTransHuge(page))
+ goto activate_locked;
+ /* Fallback to swap normal pages */
+ if (split_huge_page_to_list(page,
+ page_list))
+ goto activate_locked;
+ if (!add_to_swap(page))
+ goto activate_locked;
+ }
- may_enter_fs = 1;
+ may_enter_fs = 1;
- /* Adding to swap updated mapping */
- mapping = page_mapping(page);
+ /* Adding to swap updated mapping */
+ mapping = page_mapping(page);
+ }
} else if (unlikely(PageTransHuge(page))) {
/* Split file THP */
if (split_huge_page_to_list(page, page_list))
goto keep_locked;
}
- VM_BUG_ON_PAGE(PageTransHuge(page), page);
-
/*
* The page is mapped into the page tables of one or more
* processes. Try to unmap it here.
*/
if (page_mapped(page)) {
- if (!try_to_unmap(page, ttu_flags | TTU_BATCH_FLUSH)) {
+ enum ttu_flags flags = ttu_flags | TTU_BATCH_FLUSH;
+
+ if (unlikely(PageTransHuge(page)))
+ flags |= TTU_SPLIT_HUGE_PMD;
+ if (!try_to_unmap(page, flags)) {
nr_unmap_fail++;
goto activate_locked;
}
@@ -1313,7 +1318,11 @@ free_it:
* Is there need to periodically free_page_list? It would
* appear not as the counts should be low
*/
- list_add(&page->lru, &free_pages);
+ if (unlikely(PageTransHuge(page))) {
+ mem_cgroup_uncharge(page);
+ (*get_compound_page_dtor(page))(page);
+ } else
+ list_add(&page->lru, &free_pages);
continue;
activate_locked: