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xen/timer: remove the timer setup loop

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With the removal of the usage of the VCPU_SSHOTTMR_future flag, now
all errors from xentimer_vcpu_start_timer should be considered fatal, and
the loop is no longer needed since in case of setting the timer in the past
we will get an event interrupt right away (instead of returning ETIME).

Sponsored by:	Citrix Systems R&D
MFC after :	2 weeks
This commit is contained in:
royger 2016-05-02 16:13:55 +00:00
parent 3aa70f10cc
commit 43a683d6cb
1 changed files with 3 additions and 18 deletions
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21
sys/dev/xen/timer/timer.c
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@ -76,8 +76,6 @@ static devclass_t xentimer_devclass;
#define XENTIMER_MIN_PERIOD_IN_NSEC 100*NSEC_IN_USEC
#define XENCLOCK_RESOLUTION 10000000
#define ETIME 62 /* Xen "bad time" error */
#define XENTIMER_QUALITY 950
struct xentimer_pcpu_data {
@ -295,7 +293,7 @@ static int
xentimer_et_start(struct eventtimer *et,
sbintime_t first, sbintime_t period)
{
int error = 0, i = 0;
int error;
struct xentimer_softc *sc = et->et_priv;
int cpu = PCPU_GET(vcpu_id);
struct xentimer_pcpu_data *pcpu = DPCPU_PTR(xentimer_pcpu);
@ -312,21 +310,8 @@ xentimer_et_start(struct eventtimer *et,
first_in_ns = (((first >> 32) * NSEC_IN_SEC) +
(((uint64_t)NSEC_IN_SEC * (uint32_t)first) >> 32));
/*
* Retry any timer scheduling failures, where the hypervisor
* returns -ETIME. Sometimes even a 100us timer period isn't large
* enough, but larger period instances are relatively uncommon.
*
* XXX Remove the panics once et_start() and its consumers are
* equipped to deal with start failures.
*/
do {
if (++i == 60)
panic("can't schedule timer");
next_time = xen_fetch_vcpu_time(vcpu) + first_in_ns;
error = xentimer_vcpu_start_timer(cpu, next_time);
} while (error == -ETIME);
next_time = xen_fetch_vcpu_time(vcpu) + first_in_ns;
error = xentimer_vcpu_start_timer(cpu, next_time);
if (error)
panic("%s: Error %d setting singleshot timer to %"PRIu64"\n",
device_get_nameunit(sc->dev), error, next_time);