From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Message-Id: <20070423064916.5458.62790.sendpatchset@schroedinger.engr.sgi.com> In-Reply-To: <20070423064845.5458.2190.sendpatchset@schroedinger.engr.sgi.com> References: <20070423064845.5458.2190.sendpatchset@schroedinger.engr.sgi.com> Subject: [RFC 06/16] Variable Page Cache: Add VM_BUG_ONs to check for correct page order Date: Sun, 22 Apr 2007 23:49:16 -0700 (PDT) Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org Cc: William Lee Irwin III , Badari Pulavarty , David Chinner , Jens Axboe , Adam Litke , Christoph Lameter , Dave Hansen , Mel Gorman , Avi Kivity List-ID: Variable Page Cache: Add VM_BUG_ONs to check for correct page order Before we start changing the page order we better get some debugging in there that trips us up whenever a wrong order page shows up in a mapping. This will be helpful for converting new filesystems to utilize higher orders. Signed-off-by: Christoph Lameter --- mm/filemap.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) Index: linux-2.6.21-rc7/mm/filemap.c =================================================================== --- linux-2.6.21-rc7.orig/mm/filemap.c 2007-04-22 21:54:00.000000000 -0700 +++ linux-2.6.21-rc7/mm/filemap.c 2007-04-22 21:59:15.000000000 -0700 @@ -127,6 +127,7 @@ void remove_from_page_cache(struct page struct address_space *mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping->order != compound_order(page)); write_lock_irq(&mapping->tree_lock); __remove_from_page_cache(page); @@ -268,6 +269,7 @@ int wait_on_page_writeback_range(struct if (page->index > end) continue; + VM_BUG_ON(mapping->order != compound_order(page)); wait_on_page_writeback(page); if (PageError(page)) ret = -EIO; @@ -439,6 +441,7 @@ int add_to_page_cache(struct page *page, { int error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); + VM_BUG_ON(mapping->order != compound_order(page)); if (error == 0) { write_lock_irq(&mapping->tree_lock); error = radix_tree_insert(&mapping->page_tree, offset, page); @@ -598,8 +601,10 @@ struct page * find_get_page(struct addre read_lock_irq(&mapping->tree_lock); page = radix_tree_lookup(&mapping->page_tree, offset); - if (page) + if (page) { + VM_BUG_ON(mapping->order != compound_order(page)); page_cache_get(page); + } read_unlock_irq(&mapping->tree_lock); return page; } @@ -624,6 +629,7 @@ struct page *find_lock_page(struct addre repeat: page = radix_tree_lookup(&mapping->page_tree, offset); if (page) { + VM_BUG_ON(mapping->order != compound_order(page)); page_cache_get(page); if (TestSetPageLocked(page)) { read_unlock_irq(&mapping->tree_lock); @@ -683,6 +689,7 @@ repeat: } else if (err == -EEXIST) goto repeat; } + VM_BUG_ON(mapping->order != compound_order(page)); if (cached_page) page_cache_release(cached_page); return page; @@ -714,8 +721,10 @@ unsigned find_get_pages(struct address_s read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup(&mapping->page_tree, (void **)pages, start, nr_pages); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping->order != compound_order(pages[i])); page_cache_get(pages[i]); + } read_unlock_irq(&mapping->tree_lock); return ret; } @@ -745,6 +754,7 @@ unsigned find_get_pages_contig(struct ad if (pages[i]->mapping == NULL || pages[i]->index != index) break; + VM_BUG_ON(mapping->order != compound_order(pages[i])); page_cache_get(pages[i]); index++; } @@ -772,8 +782,10 @@ unsigned find_get_pages_tag(struct addre read_lock_irq(&mapping->tree_lock); ret = radix_tree_gang_lookup_tag(&mapping->page_tree, (void **)pages, *index, nr_pages, tag); - for (i = 0; i < ret; i++) + for (i = 0; i < ret; i++) { + VM_BUG_ON(mapping->order != compound_order(pages[i])); page_cache_get(pages[i]); + } if (ret) *index = pages[ret - 1]->index + 1; read_unlock_irq(&mapping->tree_lock); @@ -2454,6 +2466,7 @@ int try_to_release_page(struct page *pag struct address_space * const mapping = page->mapping; BUG_ON(!PageLocked(page)); + VM_BUG_ON(mapping->order != compound_order(page)); if (PageWriteback(page)) return 0; -- 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