linux_dsm_epyc7002/arch/um/os-Linux/time.c
Jeff Dike b160fb6309 uml: eliminate interrupts in the idle loop
Now, the idle loop now longer needs SIGALRM firing - it can just sleep for the
requisite amount of time and fake a timer interrupt when it finishes.

Any use of ITIMER_REAL now goes away.  disable_timer only turns off
ITIMER_VIRTUAL.  switch_timers is no longer needed, so it, and all calls, goes
away.

disable_timer now returns the amount of time remaining on the timer.
default_idle uses this to tell idle_sleep how long to sleep.  idle_sleep will
call alarm_handler if nanosleep returns 0, which is the case if it didn't
return early due to an interrupt.  Otherwise, it just returns.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:08 -07:00

71 lines
1.4 KiB
C

/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <stddef.h>
#include <errno.h>
#include <signal.h>
#include <time.h>
#include <sys/time.h>
#include "kern_constants.h"
#include "os.h"
#include "user.h"
int set_interval(void)
{
int usec = 1000000/UM_HZ;
struct itimerval interval = ((struct itimerval) { { 0, usec },
{ 0, usec } });
if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
return -errno;
return 0;
}
int timer_one_shot(int ticks)
{
unsigned long usec = ticks * 1000000 / UM_HZ;
unsigned long sec = usec / 1000000;
struct itimerval interval;
usec %= 1000000;
interval = ((struct itimerval) { { 0, 0 }, { sec, usec } });
if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
return -errno;
return 0;
}
unsigned long long disable_timer(void)
{
struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });
if(setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
printk(UM_KERN_ERR "disable_timer - setitimer failed, "
"errno = %d\n", errno);
return tv_to_nsec(&time.it_value);
}
unsigned long long os_nsecs(void)
{
struct timeval tv;
gettimeofday(&tv, NULL);
return timeval_to_ns(&tv);
}
extern void alarm_handler(int sig, struct sigcontext *sc);
void idle_sleep(unsigned long long nsecs)
{
struct timespec ts = { .tv_sec = nsecs / BILLION,
.tv_nsec = nsecs % BILLION };
if (nanosleep(&ts, &ts) == 0)
alarm_handler(SIGVTALRM, NULL);
}