diff options
| -rw-r--r-- | include/linux/mmzone.h | 2 | ||||
| -rw-r--r-- | mm/compaction.c | 3 | ||||
| -rw-r--r-- | mm/vmscan.c | 35 |
3 files changed, 38 insertions, 2 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 80acfbc9aa1..b32f3f9182c 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -166,6 +166,8 @@ static inline int is_unevictable_lru(enum lru_list l) #define ISOLATE_CLEAN ((__force isolate_mode_t)0x4) /* Isolate unmapped file */ #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8) +/* Isolate for asynchronous migration */ +#define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x10) /* LRU Isolation modes. */ typedef unsigned __bitwise__ isolate_mode_t; diff --git a/mm/compaction.c b/mm/compaction.c index 228f91b5718..da449202ff9 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -371,6 +371,9 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, continue; } + if (!cc->sync) + mode |= ISOLATE_ASYNC_MIGRATE; + /* Try isolate the page */ if (__isolate_lru_page(page, mode, 0) != 0) continue; diff --git a/mm/vmscan.c b/mm/vmscan.c index 0c78bd3bd96..45c40d66b74 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1045,8 +1045,39 @@ int __isolate_lru_page(struct page *page, isolate_mode_t mode, int file) ret = -EBUSY; - if ((mode & ISOLATE_CLEAN) && (PageDirty(page) || PageWriteback(page))) - return ret; + /* + * To minimise LRU disruption, the caller can indicate that it only + * 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)) { + /* All the caller can do on PageWriteback is block */ + if (PageWriteback(page)) + return ret; + + 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 + * without blocking + */ + mapping = page_mapping(page); + if (mapping && !mapping->a_ops->migratepage) + return ret; + } + } if ((mode & ISOLATE_UNMAPPED) && page_mapped(page)) return ret; |