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Date: Wed, 08 Apr 2015 14:37:41 +0800
From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
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Subject: Re: [Qemu-devel] [PATCH] kvm: fix slot flags sync between Qemu and
	KVM
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Li, Wanpeng" <wanpeng.li@intel.com>, Marcelo Tosatti <mtosatti@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, kvm@vger.kernel.org



On 04/08/2015 02:34 PM, Xiao Guangrong wrote:
> We noticed that KVM keeps tracking dirty for the memslots when
> live migration failed which causes bad performance due to huge
> page mapping disallowed for this kind of memslot
>
> It is caused by slot flags does not properly sync-ed between Qemu
> and KVM. Current code doing slot update depends on slot->flags
> which hopes to omit unnecessary ioctl. However, slot->flags only
> reflects the stauts of corresponding memory region, vmsave and
> live migration do dirty tracking which overset
> KVM_MEM_LOG_DIRTY_PAGES for the slot. That causes the slot status
> recorded in the flags does not exactly match the stauts in kernel.
>
> We fixed it by introducing slot->is_dirty_logging which indicates
> the dirty status in kernel so that it helps us to sync the status
> between userspace and kernel
>
> Wanpeng Li <wanpeng.li@linux.intel.com>

Sorry for the typo :( , this should be:

Reported-by: Wanpeng Li <wanpeng.li@linux.intel.com>