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Date: Tue, 18 Nov 2014 09:29:16 +0800
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Subject: Re: [Qemu-devel] =?utf-8?q?Where_is_the_VM_live_migration_code=3F?=
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To: =?utf-8?B?Smlkb25nIFhpYW8=?= <jidong.xiao@gmail.com>, =?utf-8?B?S1ZN?= <kvm@vger.kernel.org>, =?utf-8?B?cWVtdS1kZXZlbA==?= <qemu-devel@nongnu.org>

> Hi,
> 
> I saw this page:
> 
> http://www.linux-kvm.org/page/Migration.
> 
> It looks like Migration is a feature provided by KVM? But when I look
> at the Linux kernel source code, i.e., virt/kvm, and arch/x86/kvm, I
> don't see the code for this migration feature.
> 
Most of live migration code is in qemu migration.c, savevm.c, arch_init.c,
block-migration.c, and the other devices's save/load handler, .etc,
only log/sync dirty page implemented in kernel.
You can read the most important function migration_thread(),
process_incoming_migration_co().

> So I wonder where is the source code for the live migration? Is it
>purely implemented in user space? Because I see there are the
> following files in the qemu source code:
> 
> migration.c  migration-exec.c  migration-fd.c  migration-rdma.c
> migration-tcp.c  migration-unix.c
> 
> If I wish to understand the implementation of migration in Qemu/KVM,
> are these above files the ones I should read? Thanks.
> 
> -Jidong