mm, drm/i915: mark pinned shmemfs pages as unevictable

The i915 driver uses shmemfs to allocate backing storage for gem
objects. These shmemfs pages can be pinned (increased ref count) by
shmem_read_mapping_page_gfp(). When a lot of pages are pinned, vmscan
wastes a lot of time scanning these pinned pages. In some extreme case,
all pages in the inactive anon lru are pinned, and only the inactive
anon lru is scanned due to inactive_ratio, the system cannot swap and
invokes the oom-killer. Mark these pinned pages as unevictable to speed
up vmscan.

Export pagevec API check_move_unevictable_pages().

This patch was inspired by Chris Wilson's change [1].

[1]: https://patchwork.kernel.org/patch/9768741/

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Kuo-Hsin Yang <vovoy@chromium.org>
Acked-by: Michal Hocko <mhocko@suse.com> # mm part
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181106132324.17390-1-chris@chris-wilson.co.uk
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 11 insertions, 11 deletions

diff --git a/mm/vmscan.c b/mm/vmscan.c
index c7ce2c161225..0dbc493026a2 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -46,6 +46,7 @@
 #include <linux/delayacct.h>
 #include <linux/sysctl.h>
 #include <linux/oom.h>
+#include <linux/pagevec.h>
 #include <linux/prefetch.h>
 #include <linux/printk.h>
 #include <linux/dax.h>
@@ -4162,17 +4163,16 @@ int page_evictable(struct page *page)
 	return ret;
 }
 
-#ifdef CONFIG_SHMEM
 /**
- * check_move_unevictable_pages - check pages for evictability and move to appropriate zone lru list
- * @pages:	array of pages to check
- * @nr_pages:	number of pages to check
+ * check_move_unevictable_pages - check pages for evictability and move to
+ * appropriate zone lru list
+ * @pvec: pagevec with lru pages to check
  *
- * Checks pages for evictability and moves them to the appropriate lru list.
- *
- * This function is only used for SysV IPC SHM_UNLOCK.
+ * Checks pages for evictability, if an evictable page is in the unevictable
+ * lru list, moves it to the appropriate evictable lru list. This function
+ * should be only used for lru pages.
  */
-void check_move_unevictable_pages(struct page **pages, int nr_pages)
+void check_move_unevictable_pages(struct pagevec *pvec)
 {
 	struct lruvec *lruvec;
 	struct pglist_data *pgdat = NULL;
@@ -4180,8 +4180,8 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
 	int pgrescued = 0;
 	int i;
 
-	for (i = 0; i < nr_pages; i++) {
-		struct page *page = pages[i];
+	for (i = 0; i < pvec->nr; i++) {
+		struct page *page = pvec->pages[i];
 		struct pglist_data *pagepgdat = page_pgdat(page);
 
 		pgscanned++;
@@ -4213,4 +4213,4 @@ void check_move_unevictable_pages(struct page **pages, int nr_pages)
 		spin_unlock_irq(&pgdat->lru_lock);
 	}
 }
-#endif /* CONFIG_SHMEM */
+EXPORT_SYMBOL_GPL(check_move_unevictable_pages);