Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752353Ab2JALB1 (ORCPT ); Mon, 1 Oct 2012 07:01:27 -0400 Received: from smtp.ctxuk.citrix.com ([62.200.22.115]:23978 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752199Ab2JALBZ (ORCPT ); Mon, 1 Oct 2012 07:01:25 -0400 X-IronPort-AV: E=Sophos;i="4.80,515,1344211200"; d="scan'208";a="14866207" Date: Mon, 1 Oct 2012 12:00:26 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Yinghai Lu CC: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Jacob Shin , Tejun Heo , "linux-kernel@vger.kernel.org" , Konrad Rzeszutek Wilk Subject: Re: [PATCH 04/13] x86, mm: Revert back good_end setting for 64bit In-Reply-To: <1348991844-12285-5-git-send-email-yinghai@kernel.org> Message-ID: References: <1348991844-12285-1-git-send-email-yinghai@kernel.org> <1348991844-12285-5-git-send-email-yinghai@kernel.org> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2141 Lines: 57 On Sun, 30 Sep 2012, Yinghai Lu wrote: > After > > | commit 8548c84da2f47e71bbbe300f55edb768492575f7 > | Author: Takashi Iwai > | Date: Sun Oct 23 23:19:12 2011 +0200 > | > | x86: Fix S4 regression > | > | Commit 4b239f458 ("x86-64, mm: Put early page table high") causes a S4 > | regression since 2.6.39, namely the machine reboots occasionally at S4 > | resume. It doesn't happen always, overall rate is about 1/20. But, > | like other bugs, once when this happens, it continues to happen. > | > | This patch fixes the problem by essentially reverting the memory > | assignment in the older way. > > Have some page table around 512M again, that will prevent kdump to find 512M > under 768M. > > We need revert that reverting, so we could put page table high again for 64bit. > > Takashi agreed that S4 regression could be something else. > > https://lkml.org/lkml/2012/6/15/182 > > Signed-off-by: Yinghai Lu > --- > arch/x86/mm/init.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index 9f69180..aadb154 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -76,8 +76,8 @@ static void __init find_early_table_space(struct map_range *mr, > #ifdef CONFIG_X86_32 > /* for fixmap */ > tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE); > -#endif > good_end = max_pfn_mapped << PAGE_SHIFT; > +#endif > > base = memblock_find_in_range(start, good_end, tables, PAGE_SIZE); > if (!base) Isn't this going to cause init_memory_mapping to allocate pagetable pages from memory not yet mapped? Last time I spoke with HPA and Thomas about this, they seem to agree that it isn't a very good idea. Also, it is proven to cause a certain amount of headaches on Xen, see commit d8aa5ec3382e6a545b8f25178d1e0992d4927f19. -- 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/