Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755915AbaK0Mfo (ORCPT ); Thu, 27 Nov 2014 07:35:44 -0500 Received: from cpsmtpb-ews05.kpnxchange.com ([213.75.39.8]:56203 "EHLO cpsmtpb-ews05.kpnxchange.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754658AbaK0Mfm (ORCPT ); Thu, 27 Nov 2014 07:35:42 -0500 Message-ID: <1417091739.29407.95.camel@x220> Subject: Re: [PATCH v3 2/8] mm/debug-pagealloc: prepare boottime configurable on/off From: Paul Bolle To: Joonsoo Kim Cc: Valentin Rothberg , Andrew Morton , Mel Gorman , Johannes Weiner , Minchan Kim , Dave Hansen , Michal Nazarewicz , Jungsoo Son , Ingo Molnar , linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Thu, 27 Nov 2014 13:35:39 +0100 In-Reply-To: <1416816926-7756-3-git-send-email-iamjoonsoo.kim@lge.com> References: <1416816926-7756-1-git-send-email-iamjoonsoo.kim@lge.com> <1416816926-7756-3-git-send-email-iamjoonsoo.kim@lge.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4 (3.10.4-4.fc20) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 27 Nov 2014 12:35:39.0367 (UTC) FILETIME=[A6A29F70:01D00A3E] X-RcptDomain: vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Joonsoo, On Mon, 2014-11-24 at 17:15 +0900, Joonsoo Kim wrote: > Until now, debug-pagealloc needs extra flags in struct page, so we need > to recompile whole source code when we decide to use it. This is really > painful, because it takes some time to recompile and sometimes rebuild is > not possible due to third party module depending on struct page. > So, we can't use this good feature in many cases. > > Now, we have the page extension feature that allows us to insert > extra flags to outside of struct page. This gets rid of third party module > issue mentioned above. And, this allows us to determine if we need extra > memory for this page extension in boottime. With these property, we can > avoid using debug-pagealloc in boottime with low computational overhead > in the kernel built with CONFIG_DEBUG_PAGEALLOC. This will help our > development process greatly. > > This patch is the preparation step to achive above goal. debug-pagealloc > originally uses extra field of struct page, but, after this patch, it > will use field of struct page_ext. Because memory for page_ext is > allocated later than initialization of page allocator in CONFIG_SPARSEMEM, > we should disable debug-pagealloc feature temporarily until initialization > of page_ext. This patch implements this. > > v2: fix compile error on CONFIG_PAGE_POISONING > > Signed-off-by: Joonsoo Kim This patch is included in today's linux-next (ie, next-2o0141127) as commit 1e491e9be4c9 ("mm/debug-pagealloc: prepare boottime configurable on/off"). > [...] > > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 33a8acf..c7b22e7 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -10,7 +10,6 @@ > #include > #include > #include > -#include > #include > #include > #include > @@ -186,9 +185,6 @@ struct page { > void *virtual; /* Kernel virtual address (NULL if > not kmapped, ie. highmem) */ > #endif /* WANT_PAGE_VIRTUAL */ > -#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS > - unsigned long debug_flags; /* Use atomic bitops on this */ > -#endif > > #ifdef CONFIG_KMEMCHECK > /* > diff --git a/include/linux/page-debug-flags.h b/include/linux/page-debug-flags.h > deleted file mode 100644 > index 22691f61..0000000 > --- a/include/linux/page-debug-flags.h > +++ /dev/null > @@ -1,32 +0,0 @@ > -#ifndef LINUX_PAGE_DEBUG_FLAGS_H > -#define LINUX_PAGE_DEBUG_FLAGS_H > - > -/* > - * page->debug_flags bits: > - * > - * PAGE_DEBUG_FLAG_POISON is set for poisoned pages. This is used to > - * implement generic debug pagealloc feature. The pages are filled with > - * poison patterns and set this flag after free_pages(). The poisoned > - * pages are verified whether the patterns are not corrupted and clear > - * the flag before alloc_pages(). > - */ > - > -enum page_debug_flags { > - PAGE_DEBUG_FLAG_POISON, /* Page is poisoned */ > - PAGE_DEBUG_FLAG_GUARD, > -}; > - > -/* > - * Ensure that CONFIG_WANT_PAGE_DEBUG_FLAGS reliably > - * gets turned off when no debug features are enabling it! > - */ > - > -#ifdef CONFIG_WANT_PAGE_DEBUG_FLAGS > -#if !defined(CONFIG_PAGE_POISONING) && \ > - !defined(CONFIG_PAGE_GUARD) \ > -/* && !defined(CONFIG_PAGE_DEBUG_SOMETHING_ELSE) && ... */ > -#error WANT_PAGE_DEBUG_FLAGS is turned on with no debug features! > -#endif > -#endif /* CONFIG_WANT_PAGE_DEBUG_FLAGS */ > - > -#endif /* LINUX_PAGE_DEBUG_FLAGS_H */ This remove all uses of CONFIG_WANT_PAGE_DEBUG_FLAGS and CONFIG_PAGE_GUARD. So the Kconfig symbols WANT_PAGE_DEBUG_FLAGS and PAGE_GUARD are now unused. Should I submit the trivial patch to remove these symbols or is a patch that does that queued already? Paul Bolle -- 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/