From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 7 Aug 2006 20:42:16 -0700 (PDT) From: Christoph Lameter Subject: Re: 2.6.18-rc3-mm2: rcu radix tree patches break page migration In-Reply-To: <44D7E7DF.1080106@yahoo.com.au> Message-ID: References: <44D7E7DF.1080106@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: npiggin@suse.de, linux-mm@kvack.org, Lee Schermerhorn List-ID: On Tue, 8 Aug 2006, Nick Piggin wrote: > Question: can you replace the lookup_slot with a regular lookup, then > replace the pointer switch with a radix_tree_delete + radix_tree_insert > and see if that works? Ahh... Okay that makes things work the right way. Does that mean we need to get rid of radix tree replaces in general? Patch: Index: linux-2.6.18-rc3-mm2/mm/migrate.c =================================================================== --- linux-2.6.18-rc3-mm2.orig/mm/migrate.c 2006-08-07 20:21:12.985022791 -0700 +++ linux-2.6.18-rc3-mm2/mm/migrate.c 2006-08-07 20:25:28.676221751 -0700 @@ -294,7 +294,8 @@ out: static int migrate_page_move_mapping(struct address_space *mapping, struct page *newpage, struct page *page) { - struct page **radix_pointer; + struct page *radix_pointer; + long index; if (!mapping) { /* Anonymous page */ @@ -305,12 +306,14 @@ static int migrate_page_move_mapping(str write_lock_irq(&mapping->tree_lock); - radix_pointer = (struct page **)radix_tree_lookup_slot( + index = page_index(page); + + radix_pointer = (struct page *)radix_tree_lookup( &mapping->page_tree, - page_index(page)); + index); if (page_count(page) != 2 + !!PagePrivate(page) || - radix_tree_deref_slot(radix_pointer) != page) { + radix_pointer != page) { write_unlock_irq(&mapping->tree_lock); return -EAGAIN; } @@ -326,7 +329,8 @@ static int migrate_page_move_mapping(str } #endif - radix_tree_replace_slot(radix_pointer, newpage); + radix_tree_delete(&mapping->page_tree, index); + radix_tree_insert(&mapping->page_tree, index, newpage); __put_page(page); write_unlock_irq(&mapping->tree_lock); -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org