Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753726Ab0LUWl0 (ORCPT ); Tue, 21 Dec 2010 17:41:26 -0500 Received: from claw.goop.org ([74.207.240.146]:33674 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753464Ab0LUWlZ (ORCPT ); Tue, 21 Dec 2010 17:41:25 -0500 Message-ID: <4D112D13.8010208@goop.org> Date: Tue, 21 Dec 2010 14:41:23 -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 02/10] xen/p2m: change p2m_missing_* to p2m_identity_* References: <1292967460-15709-1-git-send-email-konrad.wilk@oracle.com> <1292967460-15709-3-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1292967460-15709-3-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: 8331 Lines: 230 On 12/21/2010 01:37 PM, Konrad Rzeszutek Wilk wrote: > From: Konrad Rzeszutek Wilk > > We are going to alter how we think about P2M. Most of the > P2M contains MFN, and areas that are not populated are > considered to be "missing". Missing means that the PFN > is either not set for this guest (not have that much memory > allocated) or is under the balloon driver ownership. > > We are instead now going to think of those not populated > areas as "identity." Meaning that that the PFN for which > we would get the p2m_identity we will provide the the PFN > value back instead of P2M_MISSING. Essentially treating > those regions as PFN==MFN. > This renames missing -> identity, but does it actually change the functionality? Doesn't it just leave it being misnamed? It would probably be better to fold in the actual identity implementation as well. > Signed-off-by: Konrad Rzeszutek Wilk > --- > arch/x86/xen/mmu.c | 59 ++++++++++++++++++++++++++------------------------- > 1 files changed, 30 insertions(+), 29 deletions(-) > > diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c > index 44924e5..d6d0276 100644 > --- a/arch/x86/xen/mmu.c > +++ b/arch/x86/xen/mmu.c > @@ -209,9 +209,9 @@ unsigned long xen_max_p2m_pfn __read_mostly; > #define MAX_P2M_PFN (P2M_TOP_PER_PAGE * P2M_MID_PER_PAGE * P2M_PER_PAGE) > > /* Placeholders for holes in the address space */ > -static RESERVE_BRK_ARRAY(unsigned long, p2m_missing, P2M_PER_PAGE); > -static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_missing, P2M_MID_PER_PAGE); > -static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_missing_mfn, P2M_MID_PER_PAGE); > +static RESERVE_BRK_ARRAY(unsigned long, p2m_identity, P2M_PER_PAGE); > +static RESERVE_BRK_ARRAY(unsigned long *, p2m_mid_identity, P2M_MID_PER_PAGE); > +static RESERVE_BRK_ARRAY(unsigned long, p2m_mid_identity_mfn, P2M_MID_PER_PAGE); > > static RESERVE_BRK_ARRAY(unsigned long **, p2m_top, P2M_TOP_PER_PAGE); > static RESERVE_BRK_ARRAY(unsigned long, p2m_top_mfn, P2M_TOP_PER_PAGE); > @@ -241,7 +241,7 @@ static void p2m_top_init(unsigned long ***top) > unsigned i; > > for (i = 0; i < P2M_TOP_PER_PAGE; i++) > - top[i] = p2m_mid_missing; > + top[i] = p2m_mid_identity; > } > > static void p2m_top_mfn_init(unsigned long *top) > @@ -249,7 +249,7 @@ static void p2m_top_mfn_init(unsigned long *top) > unsigned i; > > for (i = 0; i < P2M_TOP_PER_PAGE; i++) > - top[i] = virt_to_mfn(p2m_mid_missing_mfn); > + top[i] = virt_to_mfn(p2m_mid_identity_mfn); > } > > static void p2m_top_mfn_p_init(unsigned long **top) > @@ -257,7 +257,7 @@ static void p2m_top_mfn_p_init(unsigned long **top) > unsigned i; > > for (i = 0; i < P2M_TOP_PER_PAGE; i++) > - top[i] = p2m_mid_missing_mfn; > + top[i] = p2m_mid_identity_mfn; > } > > static void p2m_mid_init(unsigned long **mid) > @@ -265,7 +265,7 @@ static void p2m_mid_init(unsigned long **mid) > unsigned i; > > for (i = 0; i < P2M_MID_PER_PAGE; i++) > - mid[i] = p2m_missing; > + mid[i] = p2m_identity; > } > > static void p2m_mid_mfn_init(unsigned long *mid) > @@ -273,7 +273,7 @@ static void p2m_mid_mfn_init(unsigned long *mid) > unsigned i; > > for (i = 0; i < P2M_MID_PER_PAGE; i++) > - mid[i] = virt_to_mfn(p2m_missing); > + mid[i] = virt_to_mfn(p2m_identity); > } > > static void p2m_init(unsigned long *p2m) > @@ -300,8 +300,8 @@ void xen_build_mfn_list_list(void) > > /* Pre-initialize p2m_top_mfn to be completely missing */ > if (p2m_top_mfn == NULL) { > - p2m_mid_missing_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); > - p2m_mid_mfn_init(p2m_mid_missing_mfn); > + p2m_mid_identity_mfn = extend_brk(PAGE_SIZE, PAGE_SIZE); > + p2m_mid_mfn_init(p2m_mid_identity_mfn); > > p2m_top_mfn_p = extend_brk(PAGE_SIZE, PAGE_SIZE); > p2m_top_mfn_p_init(p2m_top_mfn_p); > @@ -310,7 +310,7 @@ void xen_build_mfn_list_list(void) > p2m_top_mfn_init(p2m_top_mfn); > } else { > /* Reinitialise, mfn's all change after migration */ > - p2m_mid_mfn_init(p2m_mid_missing_mfn); > + p2m_mid_mfn_init(p2m_mid_identity_mfn); > } > > for (pfn = 0; pfn < xen_max_p2m_pfn; pfn += P2M_PER_PAGE) { > @@ -326,15 +326,15 @@ void xen_build_mfn_list_list(void) > * they're just missing, just update the stored mfn, > * since all could have changed over a migrate. > */ > - if (mid == p2m_mid_missing) { > + if (mid == p2m_mid_identity) { > BUG_ON(mididx); > - BUG_ON(mid_mfn_p != p2m_mid_missing_mfn); > - p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_missing_mfn); > + BUG_ON(mid_mfn_p != p2m_mid_identity_mfn); > + p2m_top_mfn[topidx] = virt_to_mfn(p2m_mid_identity_mfn); > pfn += (P2M_MID_PER_PAGE - 1) * P2M_PER_PAGE; > continue; > } > > - if (mid_mfn_p == p2m_mid_missing_mfn) { > + if (mid_mfn_p == p2m_mid_identity_mfn) { > /* > * XXX boot-time only! We should never find > * missing parts of the mfn tree after > @@ -370,11 +370,11 @@ void __init xen_build_dynamic_phys_to_machine(void) > > xen_max_p2m_pfn = max_pfn; > > - p2m_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); > - p2m_init(p2m_missing); > + p2m_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); > + p2m_init(p2m_identity); > > - p2m_mid_missing = extend_brk(PAGE_SIZE, PAGE_SIZE); > - p2m_mid_init(p2m_mid_missing); > + p2m_mid_identity = extend_brk(PAGE_SIZE, PAGE_SIZE); > + p2m_mid_init(p2m_mid_identity); > > p2m_top = extend_brk(PAGE_SIZE, PAGE_SIZE); > p2m_top_init(p2m_top); > @@ -388,7 +388,7 @@ void __init xen_build_dynamic_phys_to_machine(void) > unsigned topidx = p2m_top_index(pfn); > unsigned mididx = p2m_mid_index(pfn); > > - if (p2m_top[topidx] == p2m_mid_missing) { > + if (p2m_top[topidx] == p2m_mid_identity) { > unsigned long **mid = extend_brk(PAGE_SIZE, PAGE_SIZE); > p2m_mid_init(mid); > > @@ -443,7 +443,7 @@ static bool alloc_p2m(unsigned long pfn) > top_p = &p2m_top[topidx]; > mid = *top_p; > > - if (mid == p2m_mid_missing) { > + if (mid == p2m_mid_identity) { > /* Mid level is missing, allocate a new one */ > mid = alloc_p2m_page(); > if (!mid) > @@ -451,7 +451,7 @@ static bool alloc_p2m(unsigned long pfn) > > p2m_mid_init(mid); > > - if (cmpxchg(top_p, p2m_mid_missing, mid) != p2m_mid_missing) > + if (cmpxchg(top_p, p2m_mid_identity, mid) != p2m_mid_identity) > free_p2m_page(mid); > } > > @@ -460,9 +460,9 @@ static bool alloc_p2m(unsigned long pfn) > > BUG_ON(virt_to_mfn(mid_mfn) != *top_mfn_p); > > - if (mid_mfn == p2m_mid_missing_mfn) { > + if (mid_mfn == p2m_mid_identity_mfn) { > /* Separately check the mid mfn level */ > - unsigned long missing_mfn; > + unsigned long identity_mfn; > unsigned long mid_mfn_mfn; > > mid_mfn = alloc_p2m_page(); > @@ -471,15 +471,16 @@ static bool alloc_p2m(unsigned long pfn) > > p2m_mid_mfn_init(mid_mfn); > > - missing_mfn = virt_to_mfn(p2m_mid_missing_mfn); > + identity_mfn = virt_to_mfn(p2m_mid_identity_mfn); > mid_mfn_mfn = virt_to_mfn(mid_mfn); > - if (cmpxchg(top_mfn_p, missing_mfn, mid_mfn_mfn) != missing_mfn) > + if (cmpxchg(top_mfn_p, identity_mfn, mid_mfn_mfn) != > + identity_mfn) Don't wrap this. > free_p2m_page(mid_mfn); > else > p2m_top_mfn_p[topidx] = mid_mfn; > } > > - if (p2m_top[topidx][mididx] == p2m_missing) { > + if (p2m_top[topidx][mididx] == p2m_identity) { > /* p2m leaf page is missing */ > unsigned long *p2m; > > @@ -489,7 +490,7 @@ static bool alloc_p2m(unsigned long pfn) > > p2m_init(p2m); > > - if (cmpxchg(&mid[mididx], p2m_missing, p2m) != p2m_missing) > + if (cmpxchg(&mid[mididx], p2m_identity, p2m) != p2m_identity) > free_p2m_page(p2m); > else > mid_mfn[mididx] = virt_to_mfn(p2m); > @@ -512,7 +513,7 @@ bool __set_phys_to_machine(unsigned long pfn, unsigned long mfn) > mididx = p2m_mid_index(pfn); > idx = p2m_index(pfn); > > - if (p2m_top[topidx][mididx] == p2m_missing) > + if (p2m_top[topidx][mididx] == p2m_identity) > return mfn == INVALID_P2M_ENTRY; > > p2m_top[topidx][mididx][idx] = mfn; Thanks, J -- 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/