The patch titled
revert migrate_move_mapping to use direct radix tree slot update
has been added to the -mm tree. Its filename is
page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup-update.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: revert migrate_move_mapping to use direct radix tree slot update
From: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
been fixed, we can, if Christoph agrees:
Revert migrate_page_move_mapping() to use direct radix tree
slot replacement. Fix up variable types to match modified
interfaces to radix_tree_{deref|replace}_slot().
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
Cc: Christoph Lameter <clameter@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
mm/migrate.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff -puN mm/migrate.c~page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup-update mm/migrate.c
--- a/mm/migrate.c~page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup-update
+++ a/mm/migrate.c
@@ -294,8 +294,7 @@ out:
static int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page)
{
- struct page *current_page;
- long index;
+ void **pslot;
if (!mapping) {
/* Anonymous page */
@@ -306,14 +305,11 @@ static int migrate_page_move_mapping(str
write_lock_irq(&mapping->tree_lock);
- index = page_index(page);
-
- current_page = (struct page *)radix_tree_lookup(
- &mapping->page_tree,
- index);
+ pslot = radix_tree_lookup_slot(&mapping->page_tree,
+ page_index(page));
if (page_count(page) != 2 + !!PagePrivate(page) ||
- current_page != page) {
+ (struct page *)radix_tree_deref_slot(pslot) != page) {
write_unlock_irq(&mapping->tree_lock);
return -EAGAIN;
}
@@ -321,7 +317,7 @@ static int migrate_page_move_mapping(str
/*
* Now we know that no one else is looking at the page.
*/
- get_page(newpage);
+ get_page(newpage); /* add cache reference */
#ifdef CONFIG_SWAP
if (PageSwapCache(page)) {
SetPageSwapCache(newpage);
@@ -329,9 +325,14 @@ static int migrate_page_move_mapping(str
}
#endif
- radix_tree_delete(&mapping->page_tree, index);
- radix_tree_insert(&mapping->page_tree, index, newpage);
+ radix_tree_replace_slot(pslot, newpage);
+
+ /*
+ * Drop cache reference from old page.
+ * We know this isn't the last reference.
+ */
__put_page(page);
+
write_unlock_irq(&mapping->tree_lock);
return 0;
_
Patches currently in -mm which might be from Lee.Schermerhorn@xxxxxx are
adix-tree-rcu-lockless-readside-fix-3.patch
radix-tree-cleanup-radix_tree_deref_slot-and.patch
cleanup-radix_tree_derefreplace_slot-calling-conventions.patch
page-migration-replace-radix_tree_lookup_slot-with-radix_tree_lockup-update.patch
mempolicies-fix-policy_zone-check.patch
-
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