src/patches/60055_xen-configurable-guest-devices.patch1

   1 From: jbeulich@novell.com
   2 Subject: allow number of guest devices to be configurable
   3 Patch-mainline: obsolete
   4
   5 ... and derive NR_DYNIRQS from this (rather than having a hard-coded
   6 value).
   7 Similarly, allow the number of simultaneous transmits in netback to be
   8 configurable.
   9
  10 ---
  11  drivers/xen/Kconfig                        |   19 +++++++++++++++++++
  12  drivers/xen/netback/netback.c              |    3 ++-
  13  include/asm-x86/mach-xen/asm/irq_vectors.h |    2 +-
  14  3 files changed, 22 insertions(+), 2 deletions(-)
  15
  16 --- a/drivers/xen/Kconfig
  17 +++ b/drivers/xen/Kconfig
  18 @@ -74,6 +74,15 @@ config XEN_NETDEV_BACKEND
  19           network devices to other guests via a high-performance shared-memory
  20           interface.
  21
  22 +config XEN_NETDEV_TX_SHIFT
  23 +       int "Maximum simultaneous transmit requests (as a power of 2)"
  24 +       depends on XEN_NETDEV_BACKEND
  25 +       range 5 16
  26 +       default 8
  27 +       help
  28 +         The maximum number transmits the driver can hold pending, expressed
  29 +         as the exponent of a power of 2.
  30 +
  31  config XEN_NETDEV_PIPELINED_TRANSMITTER
  32         bool "Pipelined transmitter (DANGEROUS)"
  33         depends on XEN_NETDEV_BACKEND
  34 @@ -255,6 +264,16 @@ config XEN_SYSFS
  35         help
  36           Xen hypervisor attributes will show up under /sys/hypervisor/.
  37
  38 +config XEN_NR_GUEST_DEVICES
  39 +       int "Number of guest devices"
  40 +       range 0 4032 if 64BIT
  41 +       range 0 960
  42 +       default 256 if XEN_BACKEND
  43 +       default 16
  44 +       help
  45 +         Specify the total number of virtual devices (i.e. both frontend
  46 +         and backend) that you want the kernel to be able to service.
  47 +
  48  choice
  49         prompt "Xen version compatibility"
  50         default XEN_COMPAT_030002_AND_LATER
  51 --- a/drivers/xen/netback/netback.c
  52 +++ b/drivers/xen/netback/netback.c
  53 @@ -74,7 +74,7 @@ static DECLARE_TASKLET(net_rx_tasklet, n
  54  static struct timer_list net_timer;
  55  static struct timer_list netbk_tx_pending_timer;
  56
  57 -#define MAX_PENDING_REQS 256
  58 +#define MAX_PENDING_REQS (1U << CONFIG_XEN_NETDEV_TX_SHIFT)
  59
  60  static struct sk_buff_head rx_queue;
  61
  62 @@ -1196,6 +1196,7 @@ static void net_tx_action(unsigned long
  63                 net_tx_action_dealloc();
  64
  65         mop = tx_map_ops;
  66 +       BUILD_BUG_ON(MAX_SKB_FRAGS >= MAX_PENDING_REQS);
  67         while (((NR_PENDING_REQS + MAX_SKB_FRAGS) < MAX_PENDING_REQS) &&
  68                 !list_empty(&net_schedule_list)) {
  69                 /* Get a netif from the list with work to do. */
  70 --- a/include/asm-x86/mach-xen/asm/irq_vectors.h
  71 +++ b/include/asm-x86/mach-xen/asm/irq_vectors.h
  72 @@ -44,7 +44,7 @@
  73  #endif
  74
  75  #define DYNIRQ_BASE            (PIRQ_BASE + NR_PIRQS)
  76 -#define NR_DYNIRQS             256
  77 +#define NR_DYNIRQS             (64 + CONFIG_XEN_NR_GUEST_DEVICES)
  78
  79  #define NR_IRQS                        (NR_PIRQS + NR_DYNIRQS)
  80  #define NR_IRQ_VECTORS         NR_IRQS