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 <[email protected]> --- 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
