Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753332Ab1FMN4t (ORCPT ); Mon, 13 Jun 2011 09:56:49 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:45828 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753258Ab1FMN4r (ORCPT ); Mon, 13 Jun 2011 09:56:47 -0400 From: Eric B Munson To: arnd@arndb.de Cc: akpm@linux-foundation.org, paulmck@linux.vnet.ibm.com, mingo@elte.hu, randy.dunlap@oracle.com, josh@joshtriplett.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, mgorman@suse.de, linux-mm@kvack.org, dave@linux.vnet.ibm.com, Eric B Munson Subject: [PATCH V2] Add debugging boundary check to pfn_to_page Date: Mon, 13 Jun 2011 09:56:39 -0400 Message-Id: <1307973399-7784-1-git-send-email-emunson@mgebm.net> X-Mailer: git-send-email 1.7.4.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3312 Lines: 101 Bugzilla 36192 showed a problem where pages were being accessed outside of a node boundary. It would be helpful in diagnosing this kind of problem to have pfn_to_page complain when a page is accessed outside of the node boundary. This patch adds a new debug config option which adds a WARN_ON in pfn_to_page that will complain when pages are accessed outside of the node boundary. Signed-of-by: Eric B Munson --- Changes from V1: minimize code duplication with a macro that will do the checking when configured include/asm-generic/memory_model.h | 25 ++++++++++++++++++++----- lib/Kconfig.debug | 9 +++++++++ 2 files changed, 29 insertions(+), 5 deletions(-) diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h index fb2d63f..7aa83ce 100644 --- a/include/asm-generic/memory_model.h +++ b/include/asm-generic/memory_model.h @@ -22,6 +22,16 @@ #endif /* CONFIG_DISCONTIGMEM */ +#ifdef CONFIG_MEMORY_MODEL +/* + * The flags for a page will only be zero if this page is being accessed + * outside of node boundaries. + */ +#define check_page(__page) WARN_ON(__page->flags == 0) +#else +#define check_page(__page) do{}while(0) +#endif /* CONFIG_MEMORY_MODEL */ + /* * supports 3 memory models. */ @@ -35,7 +45,9 @@ #define __pfn_to_page(pfn) \ ({ unsigned long __pfn = (pfn); \ unsigned long __nid = arch_pfn_to_nid(__pfn); \ - NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\ + struct page * __pg = NODE_DATA(__nid)->node_mem_map + arch_local_page_offset(__pfn, __nid);\ + check_page(__pg); \ + __pg; \ }) #define __page_to_pfn(pg) \ @@ -52,6 +64,7 @@ #define __page_to_pfn(page) (unsigned long)((page) - vmemmap) #elif defined(CONFIG_SPARSEMEM) + /* * Note: section's mem_map is encorded to reflect its start_pfn. * section[i].section_mem_map == mem_map's address - start_pfn; @@ -62,10 +75,12 @@ (unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \ }) -#define __pfn_to_page(pfn) \ -({ unsigned long __pfn = (pfn); \ - struct mem_section *__sec = __pfn_to_section(__pfn); \ - __section_mem_map_addr(__sec) + __pfn; \ +#define __pfn_to_page(pfn) \ +({ unsigned long __pfn = (pfn); \ + struct mem_section *__sec = __pfn_to_section(__pfn); \ + struct page *__pg = __section_mem_map_addr(__sec) + __pfn; \ + check_page(__pg); \ + __pg; \ }) #endif /* CONFIG_FLATMEM/DISCONTIGMEM/SPARSEMEM */ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index dd373c8..7870907 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -777,6 +777,15 @@ config DEBUG_MEMORY_INIT If unsure, say Y +config DEBUG_MEMORY_MODEL + bool "Debug memory model" if SPARSEMEM || DISCONTIGMEM + help + Enable this to check that page accesses are done within node + boundaries. The check will warn each time a page is requested + outside node boundaries. + + If unsure, say N + config DEBUG_LIST bool "Debug linked list manipulation" depends on DEBUG_KERNEL -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/