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SubjectRe: [PATCH] [12/58] x86_64: Add vDSO for x86-64 with gettimeofday/clock_gettime/getcpu
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On Thu, 2007-07-19 at 11:54 +0200, Andi Kleen wrote:
> +
> +static noinline int do_realtime(struct timespec *ts)
> +{
> + unsigned long seq, ns;
> + do {
> + seq = read_seqbegin(&gtod->lock);
> + ts->tv_sec = gtod->wall_time_sec;
> + ts->tv_nsec = gtod->wall_time_nsec;
> + ns = vgetns();
> + } while (unlikely(read_seqretry(&gtod->lock, seq)));
> + timespec_add_ns(ts, ns);
> + return 0;
> +}

Some thoughts ,

In the -mm kernel there is some debugging that gets injected into the
likely/unlikely macros .. If they get called from userspace it causes a
hang .. We might want to add some new set of macros to specifically
denote that they are called from userspace, not just likely/unlikely but
all the macros so we don't get mixed usage ..

Daniel

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