From: Dave Hansen <dave.hansen@intel.com>
To: "Li, Liang Z" <liang.z.li@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"mhocko@suse.com" <mhocko@suse.com>,
"mst@redhat.com" <mst@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"dgilbert@redhat.com" <dgilbert@redhat.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>
Subject: Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Thu, 15 Dec 2016 17:09:10 -0800 [thread overview]
Message-ID: <f517bfbe-18b8-6962-5c57-545f6ef47ad0@intel.com> (raw)
In-Reply-To: <F2CBF3009FA73547804AE4C663CAB28E3C32985A@shsmsx102.ccr.corp.intel.com>
On 12/15/2016 04:48 PM, Li, Liang Z wrote:
>>> 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.
>>> What's your opinion?
>> I still think 'order' makes a lot of sense. But, as you say, 57 bits is enough for
>> x86 for a while. Other architectures.... who knows?
Thinking about this some more... There are really only two cases that
matter: 4k pages and "much bigger" ones.
Squeezing each 4k page into 8 bytes of metadata helps guarantee that
this scheme won't regress over the old scheme in any cases. For bigger
ranges, 8 vs 16 bytes means *nothing*. And 16 bytes will be as good or
better than the old scheme for everything which is >4k.
How about this:
* 52 bits of 'pfn', 5 bits of 'order', 7 bits of 'length'
* One special 'length' value to mean "actual length in next 8 bytes"
That should be pretty simple to produce and decode. We have two record
sizes, but I think it is manageable.
WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave.hansen@intel.com>
To: "Li, Liang Z" <liang.z.li@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"mhocko@suse.com" <mhocko@suse.com>,
"mst@redhat.com" <mst@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"dgilbert@redhat.com" <dgilbert@redhat.com>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"virtualization@lists.linux-foundation.org"
<virtualization@lists.linux-foundation.org>,
"kirill.shutemov@linux.intel.com"
<kirill.shutemov@linux.intel.com>
Subject: Re: [Qemu-devel] [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Thu, 15 Dec 2016 17:09:10 -0800 [thread overview]
Message-ID: <f517bfbe-18b8-6962-5c57-545f6ef47ad0@intel.com> (raw)
In-Reply-To: <F2CBF3009FA73547804AE4C663CAB28E3C32985A@shsmsx102.ccr.corp.intel.com>
On 12/15/2016 04:48 PM, Li, Liang Z wrote:
>>> 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.
>>> What's your opinion?
>> I still think 'order' makes a lot of sense. But, as you say, 57 bits is enough for
>> x86 for a while. Other architectures.... who knows?
Thinking about this some more... There are really only two cases that
matter: 4k pages and "much bigger" ones.
Squeezing each 4k page into 8 bytes of metadata helps guarantee that
this scheme won't regress over the old scheme in any cases. For bigger
ranges, 8 vs 16 bytes means *nothing*. And 16 bytes will be as good or
better than the old scheme for everything which is >4k.
How about this:
* 52 bits of 'pfn', 5 bits of 'order', 7 bits of 'length'
* One special 'length' value to mean "actual length in next 8 bytes"
That should be pretty simple to produce and decode. We have two record
sizes, but I think it is manageable.
--
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next prev parent reply other threads:[~2016-12-16 1:12 UTC|newest]
Thread overview: 165+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 8:43 [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 1/5] virtio-balloon: rework deflate to add page to a list Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 2/5] virtio-balloon: define new feature bit and head struct Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 3/5] virtio-balloon: speed up inflate/deflate process Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 4/5] virtio-balloon: define flags and head for host request vq Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [PATCH kernel v5 5/5] virtio-balloon: tell host vm's unused page info Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 8:43 ` [Qemu-devel] " Liang Li
2016-11-30 8:43 ` Liang Li
2016-11-30 19:15 ` Dave Hansen
2016-11-30 19:15 ` Dave Hansen
2016-11-30 19:15 ` [Qemu-devel] " Dave Hansen
2016-11-30 19:15 ` Dave Hansen
2016-12-04 13:13 ` Li, Liang Z
2016-12-04 13:13 ` Li, Liang Z
2016-12-04 13:13 ` [Qemu-devel] " Li, Liang Z
2016-12-04 13:13 ` Li, Liang Z
2016-12-05 17:22 ` Dave Hansen
2016-12-05 17:22 ` [Qemu-devel] " Dave Hansen
2016-12-05 17:22 ` Dave Hansen
2016-12-05 17:22 ` Dave Hansen
2016-12-06 4:47 ` Li, Liang Z
2016-12-06 4:47 ` [Qemu-devel] " Li, Liang Z
2016-12-06 4:47 ` Li, Liang Z
2016-12-06 4:47 ` Li, Liang Z
2016-12-06 8:40 ` [PATCH kernel v5 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration David Hildenbrand
2016-12-06 8:40 ` [Qemu-devel] " David Hildenbrand
2016-12-06 8:40 ` David Hildenbrand
2016-12-06 8:40 ` David Hildenbrand
2016-12-07 13:35 ` Li, Liang Z
2016-12-07 13:35 ` [Qemu-devel] " Li, Liang Z
2016-12-07 13:35 ` Li, Liang Z
2016-12-07 13:35 ` Li, Liang Z
2016-12-07 15:34 ` Dave Hansen
2016-12-07 15:34 ` [Qemu-devel] " Dave Hansen
2016-12-07 15:34 ` Dave Hansen
2016-12-09 3:09 ` Li, Liang Z
2016-12-09 3:09 ` [Qemu-devel] " Li, Liang Z
2016-12-09 3:09 ` Li, Liang Z
2016-12-09 3:09 ` Li, Liang Z
2016-12-09 3:09 ` Li, Liang Z
2016-12-07 15:34 ` Dave Hansen
2016-12-07 15:42 ` David Hildenbrand
2016-12-07 15:42 ` [Qemu-devel] " David Hildenbrand
2016-12-07 15:42 ` David Hildenbrand
2016-12-07 15:45 ` Dave Hansen
2016-12-07 15:45 ` [Qemu-devel] " Dave Hansen
2016-12-07 15:45 ` Dave Hansen
2016-12-07 15:45 ` Dave Hansen
2016-12-07 16:21 ` David Hildenbrand
2016-12-07 16:21 ` [Qemu-devel] " David Hildenbrand
2016-12-07 16:21 ` David Hildenbrand
2016-12-07 16:21 ` David Hildenbrand
2016-12-07 16:57 ` Dave Hansen
2016-12-07 16:57 ` Dave Hansen
2016-12-07 16:57 ` [Qemu-devel] " Dave Hansen
2016-12-07 16:57 ` Dave Hansen
2016-12-07 18:38 ` [Qemu-devel] " Andrea Arcangeli
2016-12-07 18:38 ` Andrea Arcangeli
2016-12-07 18:38 ` Andrea Arcangeli
2016-12-07 18:38 ` Andrea Arcangeli
2016-12-07 18:44 ` Dave Hansen
2016-12-07 18:44 ` Dave Hansen
2016-12-07 18:44 ` Dave Hansen
2016-12-07 18:44 ` Dave Hansen
2016-12-07 18:58 ` Andrea Arcangeli
2016-12-07 18:58 ` Andrea Arcangeli
2016-12-07 18:58 ` Andrea Arcangeli
2016-12-07 18:58 ` Andrea Arcangeli
2016-12-07 19:54 ` Dave Hansen
2016-12-07 19:54 ` Dave Hansen
2016-12-07 19:54 ` Dave Hansen
2016-12-07 19:54 ` Dave Hansen
2016-12-07 20:28 ` Andrea Arcangeli
2016-12-07 20:28 ` Andrea Arcangeli
2016-12-07 20:28 ` Andrea Arcangeli
2016-12-07 20:28 ` Andrea Arcangeli
2016-12-09 4:45 ` Li, Liang Z
2016-12-09 4:45 ` Li, Liang Z
2016-12-09 4:45 ` Li, Liang Z
2016-12-09 4:45 ` Li, Liang Z
2016-12-09 4:53 ` Dave Hansen
2016-12-09 4:53 ` Dave Hansen
2016-12-09 4:53 ` Dave Hansen
2016-12-09 4:53 ` Dave Hansen
2016-12-09 5:35 ` Li, Liang Z
2016-12-09 5:35 ` Li, Liang Z
2016-12-09 5:35 ` Li, Liang Z
2016-12-09 5:35 ` Li, Liang Z
2016-12-09 16:42 ` Andrea Arcangeli
2016-12-09 16:42 ` Andrea Arcangeli
2016-12-09 16:42 ` Andrea Arcangeli
2016-12-09 16:42 ` Andrea Arcangeli
2016-12-14 8:20 ` Li, Liang Z
2016-12-14 8:20 ` Li, Liang Z
2016-12-14 8:20 ` Li, Liang Z
2016-12-14 8:20 ` Li, Liang Z
2016-12-14 8:59 ` Li, Liang Z
2016-12-14 8:59 ` Li, Liang Z
2016-12-14 8:59 ` Li, Liang Z
2016-12-14 8:59 ` Li, Liang Z
2016-12-15 15:34 ` Dave Hansen
2016-12-15 15:34 ` Dave Hansen
2016-12-15 15:34 ` Dave Hansen
2016-12-15 15:34 ` Dave Hansen
2016-12-15 15:54 ` Michael S. Tsirkin
2016-12-15 15:54 ` Michael S. Tsirkin
2016-12-15 15:54 ` Michael S. Tsirkin
2016-12-15 15:54 ` Michael S. Tsirkin
2016-12-16 1:12 ` Li, Liang Z
2016-12-16 1:12 ` Li, Liang Z
2016-12-16 1:12 ` Li, Liang Z
2016-12-16 1:12 ` Li, Liang Z
2016-12-16 15:40 ` Andrea Arcangeli
2016-12-16 15:40 ` Andrea Arcangeli
2016-12-16 15:40 ` Andrea Arcangeli
2016-12-17 11:56 ` Li, Liang Z
2016-12-17 11:56 ` Li, Liang Z
2016-12-17 11:56 ` Li, Liang Z
2016-12-17 11:56 ` Li, Liang Z
2016-12-16 15:40 ` Andrea Arcangeli
2016-12-16 0:48 ` Li, Liang Z
2016-12-16 0:48 ` Li, Liang Z
2016-12-16 0:48 ` Li, Liang Z
2016-12-16 0:48 ` Li, Liang Z
2016-12-16 1:09 ` Dave Hansen
2016-12-16 1:09 ` Dave Hansen [this message]
2016-12-16 1:09 ` Dave Hansen
2016-12-16 1:09 ` Dave Hansen
2016-12-16 1:38 ` Li, Liang Z
2016-12-16 1:38 ` Li, Liang Z
2016-12-16 1:38 ` Li, Liang Z
2016-12-16 1:38 ` Li, Liang Z
2016-12-16 1:40 ` Dave Hansen
2016-12-16 1:40 ` Dave Hansen
2016-12-16 1:40 ` Dave Hansen
2016-12-16 1:40 ` Dave Hansen
2016-12-16 1:43 ` Li, Liang Z
2016-12-16 1:43 ` Li, Liang Z
2016-12-16 1:43 ` Li, Liang Z
2016-12-16 1:43 ` Li, Liang Z
2016-12-16 16:01 ` Andrea Arcangeli
2016-12-16 16:01 ` Andrea Arcangeli
2016-12-16 16:01 ` Andrea Arcangeli
2016-12-16 16:01 ` Andrea Arcangeli
2016-12-17 12:39 ` Li, Liang Z
2016-12-17 12:39 ` Li, Liang Z
2016-12-17 12:39 ` Li, Liang Z
2016-12-17 12:39 ` Li, Liang Z
2016-12-07 15:42 ` David Hildenbrand
2016-12-07 13:35 ` Li, Liang Z
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