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| author |   Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-08-20 19:10:01 -0700 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-08-24 11:14:12 -0700 |
| commit | dffe2e1e1a1ddb566a76266136c312801c66dcf7 (patch) | |
| tree | 2c78da36fc090fff84ff316899f261d221155136 /drivers/xen | |
| parent | xen: use percpu interrupts for IPIs and VIRQs (diff) | |
| download | linux-dev-dffe2e1e1a1ddb566a76266136c312801c66dcf7.tar.xz linux-dev-dffe2e1e1a1ddb566a76266136c312801c66dcf7.zip | |
xen: handle events as edge-triggered
Xen events are logically edge triggered, as Xen only calls the event
upcall when an event is newly set, but not continuously as it remains set.
As a result, use handle_edge_irq rather than handle_level_irq.
This has the important side-effect of fixing a long-standing bug of
events getting lost if:
- an event's interrupt handler is running
- the event is migrated to a different vcpu
- the event is re-triggered
The most noticable symptom of these lost events is occasional lockups
of blkfront.
Many thanks to Tom Kopec and Daniel Stodden in tracking this down.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Tom Kopec <tek@acm.org>
Cc: Daniel Stodden <daniel.stodden@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Diffstat (limited to 'drivers/xen')
| -rw-r--r-- | drivers/xen/events.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 0923ccb26121..13365ba35218 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -378,7 +378,7 @@ int bind_evtchn_to_irq(unsigned int evtchn) irq = find_unbound_irq(); set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "event"); + handle_edge_irq, "event"); evtchn_to_irq[evtchn] = irq; irq_info[irq] = mk_evtchn_info(evtchn); |