Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755965Ab1BNQ1X (ORCPT ); Mon, 14 Feb 2011 11:27:23 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:47775 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755940Ab1BNQ1U (ORCPT >); Mon, 14 Feb 2011 11:27:20 -0500 Date: Mon, 14 Feb 2011 11:26:02 -0500 From: Konrad Rzeszutek Wilk To: Yinghai Lu Cc: "H. Peter Anvin" , Jeremy Fitzhardinge , Stefano Stabellini , "linux-kernel@vger.kernel.org" , "tglx@linutronix.de" , "x86@kernel.org" , Jan Beulich Subject: Re: [PATCH] x86/mm/init: respect memblock reserved regions when destroying mappings Message-ID: <20110214162602.GB11290@dumpdata.com> References: <4D50343E.1020906@kernel.org> <4D504161.2060900@kernel.org> <4D506A85.9030802@goop.org> <4D50B4B5.4050505@kernel.org> <4D519AAA.8070309@zytor.com> <4D547962.8040403@goop.org> <4D547B74.1030302@kernel.org> <4D54844B.4010007@zytor.com> <4D5488D5.2020607@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D5488D5.2020607@kernel.org> User-Agent: Mutt/1.5.20 (2009-06-14) X-Source-IP: acsmt354.oracle.com [141.146.40.154] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090204.4D5957B0.00AD:SCFMA4539814,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2455 Lines: 66 > BTW: Do we really need to cleanup initial mapping between _brk_end to _end? Did you try to revert the patch and run it under your setup? > > origin patch from jan: > > commit 498343967613183611ac37dccb2846496d954c06 > Author: Jan Beulich > Date: Wed May 6 13:06:47 2009 +0100 > > x86-64: finish cleanup_highmaps()'s job wrt. _brk_end > > With the introduction of the .brk section, special care must be taken > that no unused page table entries remain if _brk_end and _end are > separated by a 2M page boundary. cleanup_highmap() runs very early and > hence cannot take care of that, hence potential entries needing to be > removed past _brk_end must be cleared once the brk allocator has done > its job. > > [ Impact: avoids undesirable TLB aliases ] > > Signed-off-by: Jan Beulich > Signed-off-by: H. Peter Anvin > > diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c > index fd3da1d..ae4f7b5 100644 > --- a/arch/x86/mm/init.c > +++ b/arch/x86/mm/init.c > @@ -7,6 +7,7 @@ > #include > #include > #include > +#include > #include > #include > > @@ -304,8 +305,23 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, > #endif > > #ifdef CONFIG_X86_64 > - if (!after_bootmem) > + if (!after_bootmem && !start) { > + pud_t *pud; > + pmd_t *pmd; > + > mmu_cr4_features = read_cr4(); > + > + /* > + * _brk_end cannot change anymore, but it and _end may be > + * located on different 2M pages. cleanup_highmap(), however, > + * can only consider _end when it runs, so destroy any > + * mappings beyond _brk_end here. > + */ > + pud = pud_offset(pgd_offset_k(_brk_end), _brk_end); > + pmd = pmd_offset(pud, _brk_end - 1); > + while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1)) > + pmd_clear(pmd); > + } > #endif > __flush_tlb_all(); > -- 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/