src/patches/60057_xen-netback-notify-multi.patch1

   1 From: jbeulich@novell.com
   2 Subject: netback: use multicall for send multiple notifications
   3 Patch-mainline: obsolete
   4
   5 This also does a small fairness improvement since now notifications
   6 get sent in the order requests came in rather than in the inverse one.
   7
   8 Index: head-2008-12-01/drivers/xen/core/evtchn.c
   9 ===================================================================
  10 --- head-2008-12-01.orig/drivers/xen/core/evtchn.c      2008-12-03 15:54:25.000000000 +0100
  11 +++ head-2008-12-01/drivers/xen/core/evtchn.c   2008-12-03 15:54:45.000000000 +0100
  12 @@ -1270,6 +1270,21 @@ void notify_remote_via_irq(int irq)
  13  }
  14  EXPORT_SYMBOL_GPL(notify_remote_via_irq);
  15
  16 +int multi_notify_remote_via_irq(multicall_entry_t *mcl, int irq)
  17 +{
  18 +       int evtchn = evtchn_from_irq(irq);
  19 +
  20 +       BUG_ON(type_from_irq(irq) == IRQT_VIRQ);
  21 +       BUG_IF_IPI(irq);
  22 +
  23 +       if (!VALID_EVTCHN(evtchn))
  24 +               return -EINVAL;
  25 +
  26 +       multi_notify_remote_via_evtchn(mcl, evtchn);
  27 +       return 0;
  28 +}
  29 +EXPORT_SYMBOL_GPL(multi_notify_remote_via_irq);
  30 +
  31  int irq_to_evtchn_port(int irq)
  32  {
  33         BUG_IF_VIRQ_PER_CPU(irq);
  34 Index: head-2008-12-01/drivers/xen/netback/netback.c
  35 ===================================================================
  36 --- head-2008-12-01.orig/drivers/xen/netback/netback.c  2008-12-01 12:10:26.000000000 +0100
  37 +++ head-2008-12-01/drivers/xen/netback/netback.c       2008-12-01 12:10:27.000000000 +0100
  38 @@ -732,10 +732,20 @@ static void net_rx_action(unsigned long
  39                 npo.meta_cons += nr_frags + 1;
  40         }
  41
  42 -       while (notify_nr != 0) {
  43 -               irq = notify_list[--notify_nr];
  44 +       if (notify_nr == 1) {
  45 +               irq = *notify_list;
  46                 __clear_bit(irq, rx_notify);
  47                 notify_remote_via_irq(irq + DYNIRQ_BASE);
  48 +       } else {
  49 +               for (count = ret = 0; ret < notify_nr; ++ret) {
  50 +                       irq = notify_list[ret];
  51 +                       __clear_bit(irq, rx_notify);
  52 +                       if (!multi_notify_remote_via_irq(rx_mcl + count,
  53 +                                                        irq + DYNIRQ_BASE))
  54 +                               ++count;
  55 +               }
  56 +               if (HYPERVISOR_multicall(rx_mcl, count))
  57 +                       BUG();
  58         }
  59
  60         /* More work to do? */
  61 Index: head-2008-12-01/include/xen/evtchn.h
  62 ===================================================================
  63 --- head-2008-12-01.orig/include/xen/evtchn.h   2008-12-01 12:08:40.000000000 +0100
  64 +++ head-2008-12-01/include/xen/evtchn.h        2008-12-01 12:10:27.000000000 +0100
  65 @@ -179,6 +179,18 @@ static inline void notify_remote_via_evt
  66         VOID(HYPERVISOR_event_channel_op(EVTCHNOP_send, &send));
  67  }
  68
  69 +static inline void
  70 +multi_notify_remote_via_evtchn(multicall_entry_t *mcl, int port)
  71 +{
  72 +       struct evtchn_send *send = (void *)(mcl->args + 2);
  73 +
  74 +       BUILD_BUG_ON(sizeof(*send) > sizeof(mcl->args) - 2 * sizeof(*mcl->args));
  75 +       send->port = port;
  76 +       mcl->op = __HYPERVISOR_event_channel_op;
  77 +       mcl->args[0] = EVTCHNOP_send;
  78 +       mcl->args[1] = (unsigned long)send;
  79 +}
  80 +
  81  /* Clear an irq's pending state, in preparation for polling on it. */
  82  void xen_clear_irq_pending(int irq);
  83
  84 @@ -197,6 +209,7 @@ void xen_poll_irq(int irq);
  85   * by bind_*_to_irqhandler().
  86   */
  87  void notify_remote_via_irq(int irq);
  88 +int multi_notify_remote_via_irq(multicall_entry_t *, int irq);
  89  int irq_to_evtchn_port(int irq);
  90
  91  #define PIRQ_SET_MAPPING 0x0