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hyperv/vmbus: Process event timer before checking events

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And update comment.

MFC after:	1 week
Sponsored by:	Microsoft OSTC
Differential Revision:	https://reviews.freebsd.org/D6600
This commit is contained in:
Sepherosa Ziehau 2016-05-31 04:10:15 +00:00
parent ee1623827e
commit 387d355588
1 changed files with 18 additions and 17 deletions
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35
sys/dev/hyperv/vmbus/hv_vmbus_drv_freebsd.c
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@ -124,33 +124,22 @@ vmbus_msg_task(void *xsc, int pending __unused)
}
}
/**
* @brief Interrupt filter routine for VMBUS.
*
* The purpose of this routine is to determine the type of VMBUS protocol
* message to process - an event or a channel message.
*/
static inline int
hv_vmbus_isr(struct vmbus_softc *sc, struct trapframe *frame, int cpu)
{
hv_vmbus_message *msg, *msg_base;
/*
* The Windows team has advised that we check for events
* before checking for messages. This is the way they do it
* in Windows when running as a guest in Hyper-V
*/
sc->vmbus_event_proc(sc, cpu);
/* Check if there are actual msgs to be process */
msg_base = VMBUS_PCPU_GET(sc, message, cpu);
/* we call eventtimer process the message */
/*
* Check event timer.
*
* TODO: move this to independent IDT vector.
*/
msg = msg_base + VMBUS_SINT_TIMER;
if (msg->header.message_type == HV_MESSAGE_TIMER_EXPIRED) {
msg->header.message_type = HV_MESSAGE_TYPE_NONE;
/* call intrrupt handler of event timer */
vmbus_et_intr(frame);
/*
@ -175,8 +164,20 @@ hv_vmbus_isr(struct vmbus_softc *sc, struct trapframe *frame, int cpu)
}
}
/*
* Check events. Hot path for network and storage I/O data; high rate.
*
* NOTE:
* As recommended by the Windows guest fellows, we check events before
* checking messages.
*/
sc->vmbus_event_proc(sc, cpu);
/*
* Check messages. Mainly management stuffs; ultra low rate.
*/
msg = msg_base + VMBUS_SINT_MESSAGE;
if (msg->header.message_type != HV_MESSAGE_TYPE_NONE) {
if (__predict_false(msg->header.message_type != HV_MESSAGE_TYPE_NONE)) {
taskqueue_enqueue(VMBUS_PCPU_GET(sc, message_tq, cpu),
VMBUS_PCPU_PTR(sc, message_task, cpu));
}