From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp03.in.ibm.com (e28smtp03.in.ibm.com [122.248.162.3]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e28smtp03.in.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id B7C962C0089 for ; Wed, 3 Jul 2013 01:31:50 +1000 (EST) Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 2 Jul 2013 20:55:31 +0530 Received: from d28relay03.in.ibm.com (d28relay03.in.ibm.com [9.184.220.60]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 58399E0053 for ; Tue, 2 Jul 2013 21:01:21 +0530 (IST) Received: from d28av02.in.ibm.com (d28av02.in.ibm.com [9.184.220.64]) by d28relay03.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r62FW5Ra23199940 for ; Tue, 2 Jul 2013 21:02:06 +0530 Received: from d28av02.in.ibm.com (loopback [127.0.0.1]) by d28av02.in.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r62FVcVp016356 for ; Wed, 3 Jul 2013 01:31:40 +1000 From: "Aneesh Kumar K.V" To: Alexander Graf Subject: Re: [PATCH -V3 2/4] powerpc/kvm: Contiguous memory allocator based hash page table allocation In-Reply-To: <51D2EDD7.9060205@suse.de> References: <1372743918-12293-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1372743918-12293-2-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <51D2EDD7.9060205@suse.de> Date: Tue, 02 Jul 2013 21:01:37 +0530 Message-ID: <87wqp9yo4m.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain Cc: kvm@vger.kernel.org, mina86@mina86.com, linux-mm@kvack.org, paulus@samba.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, m.szyprowski@samsung.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Alexander Graf writes: > On 07/02/2013 07:45 AM, Aneesh Kumar K.V wrote: >> From: "Aneesh Kumar K.V" >> >> Powerpc architecture uses a hash based page table mechanism for mapping virtual >> addresses to physical address. The architecture require this hash page table to >> be physically contiguous. With KVM on Powerpc currently we use early reservation >> mechanism for allocating guest hash page table. This implies that we need to >> reserve a big memory region to ensure we can create large number of guest >> simultaneously with KVM on Power. Another disadvantage is that the reserved memory >> is not available to rest of the subsystems and and that implies we limit the total >> available memory in the host. >> >> This patch series switch the guest hash page table allocation to use >> contiguous memory allocator. >> >> Signed-off-by: Aneesh Kumar K.V > > Is CMA a mandatory option in the kernel? Or can it be optionally > disabled? If it can be disabled, we should keep the preallocated > fallback case around for systems that have CMA disabled. > CMA is not a mandatory option. But we have config KVM_BOOK3S_64_HV bool "KVM support for POWER7 and PPC970 using hypervisor mode in host" depends on KVM_BOOK3S_64 select MMU_NOTIFIER select CMA ie, for book3s HV we select CMA and only this CMA needs is memblock which we already support -aneesh