kernel timers

[STaTeoFMiND]

Hello,
Why in arch/x86_64/kernel/time.c:main_timer_handler , write_seqlock() locks
also
vsyscall variables?
The comment says: We also need to lock the vsyscall variables, because
both do_timer() and us change them.

On multiprocessor (like amd64 x2) the do_timer is called by local apic irq?
and if yes, local apic is
on every cpu, then all cpus calls do_timer() and increase the jiffies and
other at same time?
I'm confused!

Thanks,

-- 
Bug is not a problem, it is a feature.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.selenic.com/pipermail/kernel-mentors/attachments/20070308/cdce65c5/attachment.htm