lkml.org 
[lkml]   [2007]   [Nov]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    Date
    From
    SubjectRe: uml doesn't work on 2.6.24-rc2
    On Wed, Nov 14, 2007 at 04:26:11PM +0100, Miklos Szeredi wrote:
    > This one fixed the EINVAL messages, and now UML boots, but consumes
    > 100% CPU constantly.

    Can you disable NO_HZ and try the patch below, which WorksForMe (TM)?

    Jeff

    --
    Work email - jdike at linux dot intel dot com


    Index: linux-2.6.22/arch/um/os-Linux/time.c
    ===================================================================
    --- linux-2.6.22.orig/arch/um/os-Linux/time.c 2007-11-14 10:33:29.000000000 -0500
    +++ linux-2.6.22/arch/um/os-Linux/time.c 2007-11-26 15:50:46.000000000 -0500
    @@ -59,7 +59,7 @@ long long disable_timer(void)
    {
    struct itimerval time = ((struct itimerval) { { 0, 0 }, { 0, 0 } });

    - if(setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
    + if (setitimer(ITIMER_VIRTUAL, &time, &time) < 0)
    printk(UM_KERN_ERR "disable_timer - setitimer failed, "
    "errno = %d\n", errno);

    @@ -74,13 +74,61 @@ long long os_nsecs(void)
    return timeval_to_ns(&tv);
    }

    +#ifdef UML_CONFIG_NO_HZ
    +static int after_sleep_interval(struct timespec *ts)
    +{
    +}
    +#else
    +static inline long long timespec_to_us(const struct timespec *ts)
    +{
    + return ((long long) ts->tv_sec * UM_USEC_PER_SEC) +
    + ts->tv_nsec / UM_NSEC_PER_USEC;
    +}
    +
    +static int after_sleep_interval(struct timespec *ts)
    +{
    + int usec = UM_USEC_PER_SEC / UM_HZ;
    + long long start_usecs = timespec_to_us(ts);
    + struct timeval tv;
    + struct itimerval interval;
    +
    + /*
    + * It seems that rounding can increase the value returned from
    + * setitimer to larger than the one passed in. Over time,
    + * this will cause the remaining time to be greater than the
    + * tick interval. If this happens, then just reduce the first
    + * tick to the interval value.
    + */
    + if (start_usecs > usec)
    + start_usecs = usec;
    + tv = ((struct timeval) { .tv_sec = start_usecs / UM_USEC_PER_SEC,
    + .tv_usec = start_usecs % UM_USEC_PER_SEC });
    + interval = ((struct itimerval) { { 0, usec }, tv });
    +
    + if (setitimer(ITIMER_VIRTUAL, &interval, NULL) == -1)
    + return -errno;
    +
    + return 0;
    +}
    +#endif
    +
    extern void alarm_handler(int sig, struct sigcontext *sc);

    void idle_sleep(unsigned long long nsecs)
    {
    - struct timespec ts = { .tv_sec = nsecs / UM_NSEC_PER_SEC,
    - .tv_nsec = nsecs % UM_NSEC_PER_SEC };
    + struct timespec ts;
    +
    + /*
    + * nsecs can come in as zero, in which case, this starts a
    + * busy loop. To prevent this, reset nsecs to the tick
    + * interval if it is zero.
    + */
    + if (nsecs == 0)
    + nsecs = UM_NSEC_PER_SEC / UM_HZ;
    + ts = ((struct timespec) { .tv_sec = nsecs / UM_NSEC_PER_SEC,
    + .tv_nsec = nsecs % UM_NSEC_PER_SEC });

    if (nanosleep(&ts, &ts) == 0)
    alarm_handler(SIGVTALRM, NULL);
    + after_sleep_interval(&ts);
    }
    -
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/
    \
     
     \ /
      Last update: 2007-11-26 21:57    [W:2.809 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site