Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1258585

Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC

Show all headers | View raw

On 2015年10月26日 23:03, Alexander Duyck wrote:
> No.  I think you are missing the fact that there are 256 descriptors per
> page.  As such if you dirty just 1 you will be pulling in 255 more, of
> which you may or may not have pulled in the receive buffer for.
> 
> So for example if you have the descriptor ring size set to 256 then that
> means you are going to get whatever the descriptor ring has since you
> will be marking the entire ring dirty with every packet processed,
> however you cannot guarantee that you are going to get all of the
> receive buffers unless you go through and flush the entire ring prior to
> migrating.


Yes, that will be a problem. How about adding tag for each Rx buffer and
check the tag when deliver the Rx buffer to stack? If tag has been
overwritten, this means the packet data has been migrated.


> 
> This is why I have said you will need to do something to force the rings
> to be flushed such as initiating a PM suspend prior to migrating.  You
> need to do something to stop the DMA and flush the remaining Rx buffers
> if you want to have any hope of being able to migrate the Rx in a
> consistent state.  Beyond that the only other thing you have to worry
> about are the Rx buffers that have already been handed off to the
> stack.  However those should be handled if you do a suspend and somehow
> flag pages as dirty when they are unmapped from the DMA.
> 
> - Alex

This will be simple and maybe our first version to enable migration. But
we still hope to find a way not to disable DMA before stopping VCPU to
decrease service down time.

-- 
Best regards
Tianyu Lan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Lan Tianyu <tianyu.lan@intel.com> - 2015-10-21 19:00 +0200
  [RFC Patch 10/12] IXGBEVF: Add lock to protect tx/rx ring operation Lan Tianyu <tianyu.lan@intel.com> - 2015-10-21 19:00 +0200
    Re: [RFC Patch 10/12] IXGBEVF: Add lock to protect tx/rx ring  operation Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-22 00:00 +0200
    Re: [RFC Patch 10/12] IXGBEVF: Add lock to protect tx/rx ring  operation "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 14:50 +0200
  [RFC Patch 08/12] IXGBEVF: Rework code of finding the end transmit desc of package Lan Tianyu <tianyu.lan@intel.com> - 2015-10-21 19:00 +0200
    Re: [RFC Patch 08/12] IXGBEVF: Rework code of finding the end  transmit desc of package Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-21 23:20 +0200
      Re: [RFC Patch 08/12] IXGBEVF: Rework code of finding the end transmit  desc of package "Lan, Tianyu" <tianyu.lan@intel.com> - 2015-10-24 18:20 +0200
    Re: [RFC Patch 08/12] IXGBEVF: Rework code of finding the end  transmit desc of package "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 15:00 +0200
      Re: [RFC Patch 08/12] IXGBEVF: Rework code of finding the end transmit  desc of package "Lan, Tianyu" <tianyu.lan@intel.com> - 2015-10-24 18:10 +0200
  [RFC Patch 09/12] IXGBEVF: Add live migration support for VF driver Lan Tianyu <tianyu.lan@intel.com> - 2015-10-21 19:00 +0200
    Re: [RFC Patch 09/12] IXGBEVF: Add live migration support for VF  driver Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-21 23:50 +0200
    Re: [RFC Patch 09/12] IXGBEVF: Add live migration support for VF  driver "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 14:50 +0200
  Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Or Gerlitz <gerlitz.or@gmail.com> - 2015-10-21 20:50 +0200
    Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Alex Williamson <alex.williamson@redhat.com> - 2015-10-21 21:30 +0200
      Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-22 01:30 +0200
      Re: [Qemu-devel] [RFC Patch 00/12] IXGBE: Add live migration support  for SRIOV NIC "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 14:40 +0200
        Re: [Qemu-devel] [RFC Patch 00/12] IXGBE: Add live migration  support for SRIOV NIC Alex Williamson <alex.williamson@redhat.com> - 2015-10-22 15:10 +0200
          Re: [Qemu-devel] [RFC Patch 00/12] IXGBE: Add live migration support  for SRIOV NIC "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 15:10 +0200
      Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Or Gerlitz <gerlitz.or@gmail.com> - 2015-10-22 18:00 +0200
        Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Alex Williamson <alex.williamson@redhat.com> - 2015-10-22 18:20 +0200
  Re: [Qemu-devel] [RFC Patch 00/12] IXGBE: Add live migration support  for SRIOV NIC "Michael S. Tsirkin" <mst@redhat.com> - 2015-10-22 15:00 +0200
  Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-23 20:40 +0200
    Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Alex Williamson <alex.williamson@redhat.com> - 2015-10-23 21:10 +0200
      Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-23 22:10 +0200
    Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Lan Tianyu <tianyu.lan@intel.com> - 2015-10-26 06:50 +0100
      Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-26 16:10 +0100
        Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Lan Tianyu <tianyu.lan@intel.com> - 2015-10-29 07:30 +0100
          Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-29 08:00 +0100
            Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Lan Tianyu <tianyu.lan@intel.com> - 2015-10-29 09:50 +0100
              Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-29 17:20 +0100
                Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV  NIC Lan Tianyu <tianyu.lan@intel.com> - 2015-10-30 04:00 +0100
                Re: [RFC Patch 00/12] IXGBE: Add live migration support for SRIOV NIC Alexander Duyck <alexander.duyck@gmail.com> - 2015-10-30 19:10 +0100

csiph-web