XPDS14: Removing the Xen Linux Upstream Delta of Various Linux Distros - Luis R. Rodriguez, SUSE


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Xen is being used in production by many folks, but are they really using the upstream code? If not what are they using? At least SUSE's supported delta for the Linux kernel consists of 116 patches totaling 353,770 lines of code. Debian has 43 patches for a delta of about 1693 lines of code. What is this delta and how do we shrink it? I will give an overview of the supported Linux kernel delta for Xen at SUSE and Debian with upstream but also layout a proposed roadmap of addressing the delta in collaboration with different teams in the Xen community.

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XPDS14: Removing the Xen Linux Upstream Delta of Various Linux Distros - Luis R. Rodriguez, SUSE

  1. 1. Delta with Xen on the Linux kernel What’s up with all that delta? @mcgrof mcgrof@suse.com Luis R. Rodriguez http://www.do-not-panic.com Slides: CC BY-SA Luis R. Rodriguez | Image: CC BY-SA Torkild Retvedt
  2. 2. How big is it? Citrix: reset two years ago, mostly backports Debian: 4 microcode patches SUSE: the largest delta SLE10: 133 patches SLE11: 185 patches SLE12: 110 patches 359,913 lines of code git://gitorious.org/opensuse/kernel-source.git patches.xen/ Image: CC BY-NC-SA ecololo
  3. 3. Addressing the delta The xen wiki delta for Linux upstream tracker Luis Rodriguez: IPv6 autoconf, netback Juergen Gross: pvSCSI, PAT, 500GiB RAM Daniel Kiper: EFI Konrad Wilk: user mode pvlock Boris Ostrovsky: oprofile support ● Attitude adjustment: work upstream first (™) Is it possible? Future development always upstream ● Backport automatically Image: CC BY-SA Teza Harinaivo Ramiandrisoa
  4. 4. Needs verification pci-guestdev mem-hotplug hypercall preemption - patch posted, did it go in? multipage ring Image: CC BY-NC Sergiu Bacioiu
  5. 5. Needs work ● pvusb ● Expose ballooning limits ● Retaining tasklet in netback ● Add BLKIF_OP_PACKET, CDROM command forwarding ● CDROM removable media attribute ● CDROM avoid takeover in HVM ● DCDBAS address translation ● Netback multicall for notifications ● Interrupt trigger mode and polarity ● Logarithmic scale for ballooning ● netfront support skb coalescing ● microcode update ● MTRR support ● Remove VM_IO vestiges ● Device hotplug (MODULE_ALIAS) ● Suspend event channel support for faster checkpointing in Remus FT ● Expected to be dead code (under xen) cannot easily be verified to be dead ● Support for old hypervisor (pvops kernel on xen pre-4.0.1 hypervisor) ● blktap driver (what about blktap3?) Image: CC-BY m4tik