* Andrew Morton <[email protected]> [050821 02:15]:
> "Luck, Tony" <[email protected]> wrote:
> >
> > It has been pointed out to me that ia64 doesn't boot
> > with CONFIG_PRINTK_TIME=y. The issue is the call to
> > sched_clock() ... which on ia64 accesses some per-cpu
> > data to adjust for possible variations in processor
> > speed between different cpus. Since the per-cpu page
> > is not set up for the first few printk() calls, we die.
> >
> > Is this an issue on any other architecture? Most versions
> > of sched_clock() seem to just scale jiffies into nanoseconds,
> > so I guess they don't. s390, sparc64, x86 and x86_64 all
> > have more sophisticated versions but they don't appear to me
> > to have limitations on how early they might be called.
CONFIG_PRINTK_TIME also has a problem on at least ARM OMAP where
the IO mapping to read the clock may not be initialized when
sched_clock() is called for the first time.
I'd hate to have to test for something for CONFIG_PRINTK_TIME
every time sched_clock() is being called.
The quick fix would seem to be to only allow CONFIG_PRINTK_TIME
from kernel cmdline to make it happen a bit later. So basically
make int printk_time = 0 until command line is evaluated.
Tony
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
| |
 |