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 1SkIgZ-0005O7-59 for kexec@lists.infradead.org; Thu, 28 Jun 2012 17:39:19 +0000 Received: by mail-pb0-f49.google.com with SMTP id rq13so3656417pbb.36 for ; Thu, 28 Jun 2012 10:39:18 -0700 (PDT) From: HATAYAMA Daisuke Subject: [RFC PATCH 10/10] Add page_is_buddy for old kernels Date: Fri, 29 Jun 2012 02:39:15 +0900 Message-ID: <20120628173915.19702.53050.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 v2.6.15 to v2.6.17 buddy page is marked by the condition that PG_private flag is set and _count == 0. Unfortunately, I have yet to test this logic on these kernel versions simply because I've been failing to boot them on my box. Note that on these kernels, free list can be corrupted due to the bug that the above two conditions are not checked atomically. The reason why PG_buddy was introduced is a fix for this bug. Thus, the bug can also affect the logic based on mem_map array, which we cannot avoid definitely. Signed-off-by: HATAYAMA Daisuke --- makedumpfile.c | 17 +++++++++++++++-- 1 files changed, 15 insertions(+), 2 deletions(-) diff --git a/makedumpfile.c b/makedumpfile.c index 675b47e..b73cc64 100644 --- a/makedumpfile.c +++ b/makedumpfile.c @@ -3518,6 +3518,18 @@ exclude_free_page(void) } static int +page_is_buddy_v1(unsigned long flags, unsigned int _mapcount, + unsigned long private, unsigned int _count) +{ + if ((flags & (1UL << NUMBER(PG_private))) + && _count == 0 + && private <= ARRAY_LENGTH(zone.free_area)) + return TRUE; + + return FALSE; +} + +static int page_is_buddy_v2(unsigned long flags, unsigned int _mapcount, unsigned long private, unsigned int _count) { @@ -3544,8 +3556,9 @@ static void setup_page_is_buddy(void) { if (NUMBER(PG_buddy) == NOT_FOUND_NUMBER) { - if (SIZE(pageflags) != NOT_FOUND_STRUCTURE - && NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) != NOT_FOUND_NUMBER) + if (SIZE(pageflags) == NOT_FOUND_STRUCTURE) + info->page_is_buddy = page_is_buddy_v1; + else if (NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE) != NOT_FOUND_NUMBER) info->page_is_buddy = page_is_buddy_v3; else { MSG("Can't select page_is_buddy handler; " _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec