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Re-arm the Xen interval timer in the timer event handler. This fixes 

the case of HZ!=100, and might be beneficial otherwise.

The set_timer_op in idle_block remains, to protect against a system_time
miscalculation's causing us to block without the timer set; so, while
there, spl-protect the processed_system_time read and set_timer_op.
This commit is contained in:
jld 2006-09-10 22:25:58 +00:00
parent 6d434b9d71
commit a6927cc636
1 changed files with 14 additions and 3 deletions
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17
sys/arch/xen/xen/clock.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: clock.c,v 1.28 2006/08/16 13:23:33 yamt Exp $ */
/* $NetBSD: clock.c,v 1.29 2006/09/10 22:25:58 jld Exp $ */
/*
*
@ -34,7 +34,7 @@
#include "opt_xen.h"
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.28 2006/08/16 13:23:33 yamt Exp $");
__KERNEL_RCSID(0, "$NetBSD: clock.c,v 1.29 2006/09/10 22:25:58 jld Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@ -464,6 +464,13 @@ xen_timer_handler(void *arg, struct intrframe *regs)
processed_system_time += NS_PER_TICK;
ticks_done++;
}
/*
* Re-arm the timer here, if needed; Xen's auto-ticking while runnable
* is useful only for HZ==100, and even then may be out of phase with
* the processed_system_time steps.
*/
if (ticks_done != 0)
HYPERVISOR_set_timer_op(processed_system_time + NS_PER_TICK);
/*
* Right now, delta holds the number of ns elapsed from when the last
@ -484,12 +491,16 @@ setstatclockrate(int arg)
void
idle_block(void)
{
int s, r;
/*
* We set the timer to when we expect the next timer
* interrupt. We could set the timer to later if we could
* easily find out when we will have more work (callouts) to
* process from hardclock.
*/
if (HYPERVISOR_set_timer_op(processed_system_time + NS_PER_TICK) == 0)
s = splclock();
r = HYPERVISOR_set_timer_op(processed_system_time + NS_PER_TICK);
splx(s);
if (r == 0)
HYPERVISOR_block();
}