Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753407Ab0LUWTn (ORCPT ); Tue, 21 Dec 2010 17:19:43 -0500 Received: from claw.goop.org ([74.207.240.146]:34603 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752736Ab0LUWTm (ORCPT ); Tue, 21 Dec 2010 17:19:42 -0500 Message-ID: <4D1127FC.8060102@goop.org> Date: Tue, 21 Dec 2010 14:19:40 -0800 From: Jeremy Fitzhardinge User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk 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. References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-2-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1292967460-15709-2-git-send-email-konrad.wilk@oracle.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2676 Lines: 75 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. Also, I'm not a fan of hiding real side-effectful code in a BUG_ON predicate. > + BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY); > + } > } > > static unsigned long __init xen_release_chunk(phys_addr_t start_addr, > @@ -105,6 +112,7 @@ static unsigned long __init xen_release_chunk(phys_addr_t start_addr, > start, end, ret); > if (ret == 1) { > set_phys_to_machine(pfn, INVALID_P2M_ENTRY); Ditto on this one (I guess I forgot, or it predates the existence of __set_phys_to_machine). > + BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY); > len++; > } > } > diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c > index 43f9f02..f82bb48 100644 > --- a/drivers/xen/balloon.c > +++ b/drivers/xen/balloon.c > @@ -297,6 +297,7 @@ static int decrease_reservation(unsigned long nr_pages) > for (i = 0; i < nr_pages; i++) { > pfn = mfn_to_pfn(frame_list[i]); > set_phys_to_machine(pfn, INVALID_P2M_ENTRY); > + BUG_ON(get_phys_to_machine(pfn) != INVALID_P2M_ENTRY); > balloon_append(pfn_to_page(pfn)); > } > -- 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/