From: Juan Quintela <quintela@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Wanpeng Li <wanpeng.li@linux.intel.com>,
Liang Li <liang.z.li@intel.com>,
qemu-devel@nongnu.org, yong.y.wang@intel.com,
stefanha@redhat.com, amit.shah@redhat.com
Subject: Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration
Date: Tue, 03 Nov 2015 13:36:28 +0100 [thread overview]
Message-ID: <878u6fz2cz.fsf@emacs.mitica> (raw)
In-Reply-To: <56374F11.30309@redhat.com> (Paolo Bonzini's message of "Mon, 2 Nov 2015 12:54:57 +0100")
Paolo Bonzini <pbonzini@redhat.com> wrote:
> On 02/11/2015 08:36, Liang Li wrote:
>> The patch 3ea3b7fa9af067982f34b of kvm introduces a lazy collapsing
>> of small sptes into large sptes mechanism, which intend to solve the
>> performance drop issue if live migration fails or is canceled. The
>> rmap will be scanned in the KVM_SET_USER_MEMORY_REGION ioctl context
>> when dirty logging is stopped so as to drop the small sptes, scanning
>> the rmap and drop the small sptes is a time consuming operation which
>> will take dozens of milliseconds, the actual time depends on VM's
>> memory size. For a VM with 8GB RAM, it will take about 30ms.
>
> I'm okay with these patches. Juan, can they be included in 2.5?
Applied, thanks.
>
> However, the KVM patch is a regression too. Wanpeng, can you look into
> doing the collapsing from a work item?
>
> Thanks,
>
> Paolo
next prev parent reply other threads:[~2015-11-03 12:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-02 7:36 [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration Liang Li
2015-11-02 7:37 ` [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end & blk_mig_cleanup Liang Li
2015-11-03 12:28 ` Juan Quintela
2015-11-02 7:37 ` [Qemu-devel] [v2 RESEND 2/4] migration: rename qemu_savevm_state_cancel Liang Li
2015-11-03 12:29 ` Juan Quintela
2015-11-02 7:37 ` [Qemu-devel] [v2 RESEND 3/4] migration: rename cancel to cleanup in SaveVMHandles Liang Li
2015-11-03 12:30 ` Juan Quintela
2015-11-02 7:37 ` [Qemu-devel] [v2 RESEND 4/4] migration: code clean up Liang Li
2015-11-03 12:30 ` Juan Quintela
2015-11-02 11:54 ` [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration Paolo Bonzini
2015-11-03 12:36 ` Juan Quintela [this message]
2015-11-02 14:40 ` Stefan Hajnoczi
2015-11-03 12:23 ` Amit Shah
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