From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 1E4626B0069 for ; Wed, 14 Dec 2016 03:59:52 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id g186so14924788pgc.2 for ; Wed, 14 Dec 2016 00:59:52 -0800 (PST) Received: from mga11.intel.com (mga11.intel.com. [192.55.52.93]) by mx.google.com with ESMTPS id f1si51880039plm.190.2016.12.14.00.59.51 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 14 Dec 2016 00:59:51 -0800 (PST) From: "Li, Liang Z" Subject: RE: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Date: Wed, 14 Dec 2016 08:59:47 +0000 Message-ID: References: <1480495397-23225-1-git-send-email-liang.z.li@intel.com> <0b18c636-ee67-cbb4-1ba3-81a06150db76@redhat.com> <0b83db29-ebad-2a70-8d61-756d33e33a48@intel.com> <2171e091-46ee-decd-7348-772555d3a5e3@redhat.com> <20161207183817.GE28786@redhat.com> <20161207202824.GH28786@redhat.com> <060287c7-d1af-45d5-70ea-ad35d4bbeb84@intel.com> In-Reply-To: <060287c7-d1af-45d5-70ea-ad35d4bbeb84@intel.com> Content-Language: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: "Hansen, Dave" , Andrea Arcangeli Cc: David Hildenbrand , "kvm@vger.kernel.org" , "mhocko@suse.com" , "mst@redhat.com" , "linux-kernel@vger.kernel.org" , "qemu-devel@nongnu.org" , "linux-mm@kvack.org" , "dgilbert@redhat.com" , "pbonzini@redhat.com" , "akpm@linux-foundation.org" , "virtualization@lists.linux-foundation.org" , "kirill.shutemov@linux.intel.com" > Subject: Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for > fast (de)inflating & fast live migration >=20 > On 12/08/2016 08:45 PM, Li, Liang Z wrote: > > What's the conclusion of your discussion? It seems you want some > > statistic before deciding whether to ripping the bitmap from the ABI, > > am I right? >=20 > I think Andrea and David feel pretty strongly that we should remove the > bitmap, unless we have some data to support keeping it. I don't feel as > strongly about it, but I think their critique of it is pretty valid. I t= hink the > consensus is that the bitmap needs to go. >=20 > The only real question IMNHO is whether we should do a power-of-2 or a > length. But, if we have 12 bits, then the argument for doing length is p= retty > strong. We don't need anywhere near 12 bits if doing power-of-2. Just found the MAX_ORDER should be limited to 12 if use length instead of o= rder, If the MAX_ORDER is configured to a value bigger than 12, it will make thin= gs more complex to handle this case.=20 If use order, we need to break a large memory range whose length is not the= power of 2 into several small ranges, it also make the code complex. It seems we leave too many bit for the pfn, and the bits leave for length = is not enough, How about keep 45 bits for the pfn and 19 bits for length, 45 bits for pfn = can cover 57 bits physical address, that should be enough in the near feature.=20 What's your opinion? thanks! Liang =20 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org