We have an elaborate dirty/writeback throttling mechanism inside the
reclaim scanner, but for that to work the pages have to go through
shrink_page_list() and get counted for what they are. Otherwise, we
mess up the LRU order and don't match reclaim speed to writeback.
Especially during deactivation, there is never a reason to skip dirty
pages; nothing is even trying to write them out from there. Don't mess
up the LRU order for nothing, shuffle these pages along.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/mmzone.h | 2 --
mm/vmscan.c | 14 ++------------
2 files changed, 2 insertions(+), 14 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index df992831fde7..338a786a993f 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -236,8 +236,6 @@ struct lruvec {
#define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
#define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
-/* Isolate clean file */
-#define ISOLATE_CLEAN ((__force isolate_mode_t)0x1)
/* Isolate unmapped file */
#define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x2)
/* Isolate for asynchronous migration */
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 7bb23ff229b6..0d05f7f3b532 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -87,6 +87,7 @@ struct scan_control {
/* The highest zone to isolate pages for reclaim from */
enum zone_type reclaim_idx;
+ /* Writepage batching in laptop mode; RECLAIM_WRITE */
unsigned int may_writepage:1;
/* Can mapped pages be reclaimed? */
@@ -1373,13 +1374,10 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
* wants to isolate pages it will be able to operate on without
* blocking - clean pages for the most part.
*
- * ISOLATE_CLEAN means that only clean pages should be isolated. This
- * is used by reclaim when it is cannot write to backing storage
- *
* ISOLATE_ASYNC_MIGRATE is used to indicate that it only wants to pages
* that it is possible to migrate without blocking
*/
- if (mode & (ISOLATE_CLEAN|ISOLATE_ASYNC_MIGRATE)) {
+ if (mode & ISOLATE_ASYNC_MIGRATE) {
/* All the caller can do on PageWriteback is block */
if (PageWriteback(page))
return ret;
@@ -1387,10 +1385,6 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode)
if (PageDirty(page)) {
struct address_space *mapping;
- /* ISOLATE_CLEAN means only clean pages */
- if (mode & ISOLATE_CLEAN)
- return ret;
-
/*
* Only pages without mappings or that have a
* ->migratepage callback are possible to migrate
@@ -1731,8 +1725,6 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec,
if (!sc->may_unmap)
isolate_mode |= ISOLATE_UNMAPPED;
- if (!sc->may_writepage)
- isolate_mode |= ISOLATE_CLEAN;
spin_lock_irq(&pgdat->lru_lock);
@@ -1929,8 +1921,6 @@ static void shrink_active_list(unsigned long nr_to_scan,
if (!sc->may_unmap)
isolate_mode |= ISOLATE_UNMAPPED;
- if (!sc->may_writepage)
- isolate_mode |= ISOLATE_CLEAN;
spin_lock_irq(&pgdat->lru_lock);
--
2.11.0
--
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