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authorChristoph Lameter <clameter@engr.sgi.com>2006-03-14 19:50:19 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-14 21:43:02 -0800
commit4983da07f1e2e8dc81cb9d640fbf35b899cdbdf2 (patch)
tree9c238114f029d1d22bc55f47e8d95ef7335c540d /mm
parente843e280cbe218fc8387339806d344708dee348a (diff)
downloadlinux-linaro-stable-4983da07f1e2e8dc81cb9d640fbf35b899cdbdf2.tar.gz
[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')
-rw-r--r--mm/vmscan.c18
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);