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From: "Radim Krčmář" <rkrcmar@redhat.com>
To: "Cao, Lei" <Lei.Cao@stratus.com>
Cc: "Huang, Kai" <kai.huang@linux.intel.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [PATCH 3/6] KVM: Dirty memory tracking for performant checkpointing and improved live migration
Date: Wed, 4 May 2016 20:57:34 +0200	[thread overview]
Message-ID: <20160504185734.GC27590@potion> (raw)
In-Reply-To: <BL2PR08MB4815DF7610040F4C0BCBCE8F07B0@BL2PR08MB481.namprd08.prod.outlook.com>

2016-05-04 18:33+0000, Cao, Lei:
> On 5/4/2016 1:15 PM, Cao, Lei wrote:
>> On 5/4/2016 9:13 AM, Radim Krčmář wrote:
>>> Good designs so far seem to be:
>>>  memslot -> lockless radix tree
>>> and
>>>  vcpu -> memslot -> list  (memslot -> vcpu -> list)
>>>
>> 
>> There is no need for lookup, the dirty log is fetched in sequence, so why use
>> radix tree with added complexity but no benefit?
>> 
>> List can be designed to be lockless, so memslot -> lockless fixed list?
> 
> Never mind, lookup is needed to avoid duplicates. We can use list+bitmap, but
> it's obviously not as efficient as radix tree.

Are duplicates a significant problem?

(The dirtied page is marked as dirty, so we should have zero to very few
 duplicates, depending on how dirtying and vm-exit on write to clean page
 cooperate.  Duplicates don't introduce any bugs and we could also check
 last few entries in the list to weed out most likely cases.)

  reply	other threads:[~2016-05-04 18:57 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <201604261855.u3QItn85024244@dev1.sn.stratus.com>
2016-04-26 19:24 ` [PATCH 3/6] KVM: Dirty memory tracking for performant checkpointing and improved live migration Cao, Lei
2016-04-28  9:13   ` Huang, Kai
2016-04-28 19:58     ` Cao, Lei
2016-04-29 18:19       ` Radim Krčmář
2016-05-02 15:24         ` Cao, Lei
2016-05-02 15:46           ` Radim Krčmář
2016-05-02 15:51             ` Cao, Lei
2016-05-03  6:06           ` Huang, Kai
2016-05-03 14:11             ` Radim Krčmář
2016-05-04  7:45               ` Huang, Kai
2016-05-04 13:13                 ` Radim Krčmář
2016-05-04 13:51                   ` Cao, Lei
2016-05-04 17:15                   ` Cao, Lei
2016-05-04 18:33                     ` Cao, Lei
2016-05-04 18:57                       ` Radim Krčmář [this message]
2016-05-06  9:46                         ` Kai Huang
2016-05-06 12:09                           ` Radim Krčmář
2016-05-06 15:13                             ` Cao, Lei
2016-05-06 16:04                               ` Radim Krčmář
2016-05-24 17:19                                 ` Cao, Lei
2016-06-30 13:49                                 ` Cao, Lei
2016-05-07  1:48                             ` Kai Huang
2016-05-04 19:27                     ` Radim Krčmář
2016-05-05 16:26                       ` Radim Krčmář
2016-05-06 15:19                         ` Cao, Lei

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