From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pb0-f49.google.com ([209.85.160.49]) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1SkIgJ-0005O7-Pd for kexec@lists.infradead.org; Thu, 28 Jun 2012 17:39:04 +0000 Received: by mail-pb0-f49.google.com with SMTP id rq13so3656417pbb.36 for ; Thu, 28 Jun 2012 10:39:03 -0700 (PDT) From: HATAYAMA Daisuke Subject: [RFC PATCH 08/10] Add page_is_buddy for recent kernels Date: Fri, 29 Jun 2012 02:39:00 +0900 Message-ID: <20120628173900.19702.3277.stgit@fedora-machine> In-Reply-To: <20120628173757.19702.75678.stgit@fedora-machine> References: <20120628173757.19702.75678.stgit@fedora-machine> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: kumagai-atsushi@mxc.nes.nec.co.jp Cc: kexec@lists.infradead.org On kernels from v2.6.38 and later kernels, buddy page is marked by _mapcount == PAGE_BUDDY_MAPCOUNT_VALUE, which varies once as follows: kernel version | PAGE_BUDDY_MAPCOUNT_VALUE ------------------+-------------------------- v2.6.38 | -2 v2.6.39 and later | -128 One more notice is that _mapcount shares its memory with other fields for SLAB/SLUB when PG_slab is set. We need to check if PG_slab is set or not before looking up _mapcount value. Signed-off-by: HATAYAMA Daisuke --- makedumpfile.c | 30 ++++++++++++++++++++++++++++++ 1 files changed, 30 insertions(+), 0 deletions(-) diff --git a/makedumpfile.c b/makedumpfile.c index 37c371e..aea956f 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -55,6 +55,8 @@ do { \ *ptr_long_table = value; \ } while (0) +static void setup_page_is_buddy(void); + void initialize_tables(void) { @@ -2733,6 +2735,9 @@ out: if (!get_value_for_old_linux()) return FALSE; + if (info->dump_level & DL_EXCLUDE_FREE_CONST) + setup_page_is_buddy(); + return TRUE; } @@ -3512,6 +3517,31 @@ exclude_free_page(void) return TRUE; } +static int +page_is_buddy_v3(unsigned long flags, unsigned int _mapcount, + unsigned long private, unsigned int _count) +{ + if (flags & (1UL << NUMBER(PG_slab))) + return FALSE; + + if (_mapcount == (int)NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE)) + return TRUE; + + return FALSE; +} + +static void +setup_page_is_buddy(void) +{ + if (NUMBER(PG_buddy) == NOT_FOUND_NUMBER + && SIZE(pageflags) != NOT_FOUND_STRUCTURE + && NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) != NOT_FOUND_NUMBER) + info->page_is_buddy = page_is_buddy_v3; + + MSG("Can't select page_is_buddy handler; " + "filtering free pages is disabled.\n"); +} + /* * If using a dumpfile in kdump-compressed format as a source file * instead of /proc/vmcore, 1st-bitmap of a new dumpfile must be _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec