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Re: [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end & blk_mi
From: |
Juan Quintela |
Subject: |
Re: [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end & blk_mig_cleanup |
Date: |
Tue, 03 Nov 2015 13:28:42 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.5 (gnu/linux) |
Liang Li <address@hidden> 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 <address@hidden>
> Reviewed-by: Paolo Bonzini <address@hidden>
Reviewed-by: Juan Quintela <address@hidden>
And the naming makes more sense even, thanks
- [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
- Re: [Qemu-devel] [v2 RESEND 1/4] migration: defer migration_end & blk_mig_cleanup,
Juan Quintela <=
- [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, 2015/11/02
- 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