Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752980Ab0LVOxl (ORCPT ); Wed, 22 Dec 2010 09:53:41 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:59559 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751292Ab0LVOxk (ORCPT >); Wed, 22 Dec 2010 09:53:40 -0500 Date: Wed, 22 Dec 2010 09:53:27 -0500 From: Konrad Rzeszutek Wilk To: Jeremy Fitzhardinge Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, Jan Beulich , xen-devel@lists.xensource.com, Konrad Rzeszutek Wilk Subject: Re: [PATCH 01/10] xen: Make all reserved pages for the balloon be INVALID_P2M_ENTRY. Message-ID: <20101222145327.GA1760@dumpdata.com> References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-2-git-send-email-konrad.wilk@oracle.com> <4D1127FC.8060102@goop.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D1127FC.8060102@goop.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2129 Lines: 56 On Tue, Dec 21, 2010 at 02:19:40PM -0800, Jeremy Fitzhardinge wrote: > On 12/21/2010 01:37 PM, Konrad Rzeszutek Wilk wrote: > > This patch prepares ourselves for the case where void entries in the P2M > > tree structure do not necessarily imply that the pages are missing. > > With this, we diligently set regions that will be used by the > > balloon driver to be INVALID_P2M_ENTRY and under the ownership > > of the balloon driver. > > > > Signed-off-by: Konrad Rzeszutek Wilk > > --- > > arch/x86/xen/setup.c | 8 ++++++++ > > drivers/xen/balloon.c | 1 + > > 2 files changed, 9 insertions(+), 0 deletions(-) > > > > diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c > > index b5a7f92..d984d36 100644 > > --- a/arch/x86/xen/setup.c > > +++ b/arch/x86/xen/setup.c > > @@ -52,6 +52,8 @@ phys_addr_t xen_extra_mem_start, xen_extra_mem_size; > > > > static __init void xen_add_extra_mem(unsigned long pages) > > { > > + unsigned long pfn; > > + > > u64 size = (u64)pages * PAGE_SIZE; > > u64 extra_start = xen_extra_mem_start + xen_extra_mem_size; > > > > @@ -66,6 +68,11 @@ static __init void xen_add_extra_mem(unsigned long pages) > > xen_extra_mem_size += size; > > > > xen_max_p2m_pfn = PFN_DOWN(extra_start + size); > > + > > + for (pfn = PFN_DOWN(extra_start); pfn <= xen_max_p2m_pfn; pfn++) { > > + BUG_ON(!set_phys_to_machine(pfn, INVALID_P2M_ENTRY)); > > Use __set_phys_to_machine where you don't expect (or can't allow) any > allocation. Are you OK with me moving then this check: if (unlikely(xen_feature(XENFEAT_auto_translated_physmap))) { BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY); return true; } from set_phys_to_machine to __set_phys_to_machine? > > Also, I'm not a fan of hiding real side-effectful code in a BUG_ON > predicate. Ok. Will expunge these. -- 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/