diff options
| author | Mel Gorman <mgorman@suse.de> | 2012-01-12 17:19:38 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-12 20:13:09 -0800 |
| commit | c82449352854ff09e43062246af86bdeb628f0c3 (patch) | |
| tree | 9cb8052e425c8cdab24ac41e83bbb672832ce54e | |
| parent | b969c4ab9f182a6e1b2a0848be349f99714947b0 (diff) | |
mm: compaction: make isolate_lru_page() filter-aware again
Commit 39deaf85 ("mm: compaction: make isolate_lru_page() filter-aware")
noted that compaction does not migrate dirty or writeback pages and that
is was meaningless to pick the page and re-add it to the LRU list. This
had to be partially reverted because some dirty pages can be migrated by
compaction without blocking.
This patch updates "mm: compaction: make isolate_lru_page" by skipping
over pages that migration has no possibility of migrating to minimise LRU
disruption.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel<riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andy Isaacson <adi@hexapodia.org>
Cc: Nai Xia <nai.xia@gmail.com>
Cc: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -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 42e544cd4c9..2038b90ca6e 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -177,6 +177,8 @@ struct lruvec { #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 d31e64becb3..fb291585e1b 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -349,6 +349,9 @@ 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 cb68c53db4e..efbcab1c8f5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1075,8 +1075,39 @@ 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; |