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Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migrat
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration |
Date: |
Mon, 2 Nov 2015 12:54:57 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
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?
However, the KVM patch is a regression too. Wanpeng, can you look into
doing the collapsing from a work item?
Thanks,
Paolo
- [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration, Liang Li, 2015/11/02
- [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end & blk_mig_cleanup, Liang Li, 2015/11/02
- [Qemu-devel] [v2 RESEND 2/4] migration: rename qemu_savevm_state_cancel, Liang Li, 2015/11/02
- [Qemu-devel] [v2 RESEND 4/4] migration: code clean up, Liang Li, 2015/11/02
- [Qemu-devel] [v2 RESEND 3/4] migration: rename cancel to cleanup in SaveVMHandles, Liang Li, 2015/11/02
- Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration,
Paolo Bonzini <=
- Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration, Stefan Hajnoczi, 2015/11/02
- Re: [Qemu-devel] [v2 RESEND 0/4] Fix long vm downtime during live migration, Amit Shah, 2015/11/03