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| author | Christoph Lameter <clameter@engr.sgi.com> | 2006-03-14 19:50:19 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-14 21:43:02 -0800 |
| commit | 4983da07f1e2e8dc81cb9d640fbf35b899cdbdf2 (patch) | |
| tree | 9c238114f029d1d22bc55f47e8d95ef7335c540d /mm/vmscan.c | |
| parent | e843e280cbe218fc8387339806d344708dee348a (diff) | |
| download | linux-4983da07f1e2e8dc81cb9d640fbf35b899cdbdf2.tar.bz2 | |
[PATCH] page migration: fail if page is in a vma flagged VM_LOCKED
page migration currently simply retries a couple of times if try_to_unmap()
fails without inspecting the return code.
However, SWAP_FAIL indicates that the page is in a vma that has the
VM_LOCKED flag set (if ignore_refs ==1). We can check for that return code
and avoid retrying the migration.
migrate_page_remove_references() now needs to return a reason why the
failure occured. So switch migrate_page_remove_references to use -Exx
style error messages.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm/vmscan.c')
| -rw-r--r-- | mm/vmscan.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index 7ccf763bb30b..4fe7e3aa02e2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -700,7 +700,7 @@ int migrate_page_remove_references(struct page *newpage, * the page. */ if (!mapping || page_mapcount(page) + nr_refs != page_count(page)) - return 1; + return -EAGAIN; /* * Establish swap ptes for anonymous pages or destroy pte @@ -721,13 +721,15 @@ int migrate_page_remove_references(struct page *newpage, * If the page was not migrated then the PageSwapCache bit * is still set and the operation may continue. */ - try_to_unmap(page, 1); + if (try_to_unmap(page, 1) == SWAP_FAIL) + /* A vma has VM_LOCKED set -> Permanent failure */ + return -EPERM; /* * Give up if we were unable to remove all mappings. */ if (page_mapcount(page)) - return 1; + return -EAGAIN; write_lock_irq(&mapping->tree_lock); @@ -738,7 +740,7 @@ int migrate_page_remove_references(struct page *newpage, if (!page_mapping(page) || page_count(page) != nr_refs || *radix_pointer != page) { write_unlock_irq(&mapping->tree_lock); - return 1; + return -EAGAIN; } /* @@ -813,10 +815,14 @@ EXPORT_SYMBOL(migrate_page_copy); */ int migrate_page(struct page *newpage, struct page *page) { + int rc; + BUG_ON(PageWriteback(page)); /* Writeback must be complete */ - if (migrate_page_remove_references(newpage, page, 2)) - return -EAGAIN; + rc = migrate_page_remove_references(newpage, page, 2); + + if (rc) + return rc; migrate_page_copy(newpage, page); |