Messages in this thread Patch in this message | | | Subject | [PATCH 2.6.18-rc6.mm2] revert migrate_move_mapping to use direct radix tree slot update | From | Lee Schermerhorn <> | Date | Wed, 13 Sep 2006 15:09:34 -0400 |
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Now that the problem with the rcu radix tree replace slot function has 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@hp.com>
mm/migrate.c | 23 ++++++++++++----------- 1 files changed, 12 insertions(+), 11 deletions(-)
Index: linux-2.6.18-rc6-mm2/mm/migrate.c =================================================================== --- linux-2.6.18-rc6-mm2.orig/mm/migrate.c 2006-09-13 11:39:14.000000000 -0400 +++ linux-2.6.18-rc6-mm2/mm/migrate.c 2006-09-13 11:42:36.000000000 -0400 @@ -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;
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