# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1201267419 0
# Node ID 3f5dec2011b0861d24a45dafa6e5b8d2b1033ce5
# Parent 78a29cf8476b6e6720edbfb4c89c3809be227ffe
[PV-on-HVM] Process event channels notifications in round-robin order
Signed-off-by: Takanori Kasai <kasai.takanori@xxxxxxxxxxxxxx>
Signed-off-by: Kouya Shimura <kouya@xxxxxxxxxxxxxx>
---
unmodified_drivers/linux-2.6/platform-pci/evtchn.c | 62 ++++++++++++++++++---
1 files changed, 55 insertions(+), 7 deletions(-)
diff -r 78a29cf8476b -r 3f5dec2011b0
unmodified_drivers/linux-2.6/platform-pci/evtchn.c
--- a/unmodified_drivers/linux-2.6/platform-pci/evtchn.c Fri Jan 25
13:22:52 2008 +0000
+++ b/unmodified_drivers/linux-2.6/platform-pci/evtchn.c Fri Jan 25
13:23:39 2008 +0000
@@ -254,6 +254,15 @@ void notify_remote_via_irq(int irq)
}
EXPORT_SYMBOL(notify_remote_via_irq);
+static DEFINE_PER_CPU(unsigned int, last_processed_l1i) = { BITS_PER_LONG - 1
};
+static DEFINE_PER_CPU(unsigned int, last_processed_l2i) = { BITS_PER_LONG - 1
};
+
+static inline unsigned long active_evtchns(unsigned int cpu, shared_info_t *sh,
+ unsigned int idx)
+{
+ return (sh->evtchn_pending[idx] & ~sh->evtchn_mask[idx]);
+}
+
static irqreturn_t evtchn_interrupt(int irq, void *dev_id
#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,19)
, struct pt_regs *regs
@@ -262,7 +271,8 @@ static irqreturn_t evtchn_interrupt(int
#endif
)
{
- unsigned int l1i, port;
+ unsigned int l1i, l2i, port;
+ unsigned long masked_l1, masked_l2;
/* XXX: All events are bound to vcpu0 but irq may be redirected. */
int cpu = 0; /*smp_processor_id();*/
irq_handler_t handler;
@@ -271,13 +281,42 @@ static irqreturn_t evtchn_interrupt(int
unsigned long l1, l2;
v->evtchn_upcall_pending = 0;
- /* NB. No need for a barrier here -- XCHG is a barrier on x86. */
+
+#ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
+ /* Clear master flag /before/ clearing selector flag. */
+ rmb();
+#endif
l1 = xchg(&v->evtchn_pending_sel, 0);
+
+ l1i = per_cpu(last_processed_l1i, cpu);
+ l2i = per_cpu(last_processed_l2i, cpu);
+
while (l1 != 0) {
- l1i = __ffs(l1);
- l1 &= ~(1 << l1i);
- while ((l2 = s->evtchn_pending[l1i] & ~s->evtchn_mask[l1i])) {
- port = (l1i * BITS_PER_LONG) + __ffs(l2);
+
+ l1i = (l1i + 1) % BITS_PER_LONG;
+ masked_l1 = l1 & ((~0UL) << l1i);
+
+ if (masked_l1 == 0) { /* if we masked out all events, wrap
around to the beginning */
+ l1i = BITS_PER_LONG - 1;
+ l2i = BITS_PER_LONG - 1;
+ continue;
+ }
+ l1i = __ffs(masked_l1);
+
+ do {
+ l2 = active_evtchns(cpu, s, l1i);
+
+ l2i = (l2i + 1) % BITS_PER_LONG;
+ masked_l2 = l2 & ((~0UL) << l2i);
+
+ if (masked_l2 == 0) { /* if we masked out all events,
move on */
+ l2i = BITS_PER_LONG - 1;
+ break;
+ }
+ l2i = __ffs(masked_l2);
+
+ /* process port */
+ port = (l1i * BITS_PER_LONG) + l2i;
synch_clear_bit(port, &s->evtchn_pending[0]);
irq = evtchn_to_irq[port];
@@ -303,7 +342,16 @@ static irqreturn_t evtchn_interrupt(int
spin_lock(&irq_evtchn[irq].lock);
irq_evtchn[irq].in_handler = 0;
spin_unlock(&irq_evtchn[irq].lock);
- }
+
+ /* if this is the final port processed, we'll pick up
here+1 next time */
+ per_cpu(last_processed_l1i, cpu) = l1i;
+ per_cpu(last_processed_l2i, cpu) = l2i;
+
+ } while (l2i != BITS_PER_LONG - 1);
+
+ l2 = active_evtchns(cpu, s, l1i);
+ if (l2 == 0) /* we handled all ports, so we can clear the
selector bit */
+ l1 &= ~(1UL << l1i);
}
return IRQ_HANDLED;
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