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| author | Mel Gorman <mgorman@suse.de> | 2012-01-12 17:19:38 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-01 12:27:17 -0700 |
| commit | a7e32d7a2a801b7838b4159e9d73ea86f68ae002 (patch) | |
| tree | 2eb36db6a3b61cc42974dfd4a15aef2195cd1d59 /mm | |
| parent | c17a36656685a2af6ea9e99fa243a7103b643d12 (diff) | |
| download | lwn-a7e32d7a2a801b7838b4159e9d73ea86f68ae002.tar.gz lwn-a7e32d7a2a801b7838b4159e9d73ea86f68ae002.zip | |
mm: compaction: make isolate_lru_page() filter-aware again
commit c82449352854ff09e43062246af86bdeb628f0c3 upstream.
Stable note: Not tracked in Bugzilla. A fix aimed at preserving page aging
information by reducing LRU list churning had the side-effect of
reducing THP allocation success rates. This was part of a series
to restore the success rates while preserving the reclaim fix.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/compaction.c | 3 | ||||
| -rw-r--r-- | mm/vmscan.c | 35 |
2 files changed, 36 insertions, 2 deletions
diff --git a/mm/compaction.c b/mm/compaction.c index 228f91b57182..da449202ff9d 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 0c78bd3bd964..45c40d66b747 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; |