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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <1446449823-25049-2-git-send-email-liang.z.li@intel.com> (Liang
	Li's message of "Mon, 2 Nov 2015 15:37:00 +0800")
References: <1446449823-25049-1-git-send-email-liang.z.li@intel.com>
	<1446449823-25049-2-git-send-email-liang.z.li@intel.com>
Date: Tue, 03 Nov 2015 13:28:42 +0100
Message-ID: <87si4nz2px.fsf@emacs.mitica>
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Subject: Re: [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end &
	blk_mig_cleanup
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To: Liang Li <liang.z.li@intel.com>
Cc: amit.shah@redhat.com, pbonzini@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, yong.y.wang@intel.com

Liang Li <liang.z.li@intel.com> wrote:
> Because of the patch 3ea3b7fa9af067982f34b of kvm, which introduces a
> lazy collapsing of small sptes into large sptes mechanism, now
> migration_end() is a time consuming operation because it calls
> memroy_global_dirty_log_stop(), which will trigger the dropping of small
> sptes operation and takes about dozens of milliseconds, so call
> migration_end() before all the vmsate data has already been transferred
> to the destination will prolong VM downtime. This operation should be
> deferred after all the data has been transferred to the destination.
>
> blk_mig_cleanup() can be deferred too.
>
> For a VM with 8G RAM, this patch can reduce the VM downtime about 30 ms.
>
> Signed-off-by: Liang Li <liang.z.li@intel.com>
> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

And the naming makes more sense even, thanks