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SubjectRe: [PATCH #2] console lock grabbed too early in printk...
> > is not held (which is the only case that matters, because otherwise,
> > access would block on the console_lock currently), we have the following
> > (for the x86 at least, the others are similar):
> >
> > spin_lock:
> > "xchgb %b0,%1"

> The xchgb is a locked bus access so takes an awful lot longer, especially on
> earlier cpus

Okay, so especially in SMP systems where you actually have to lock a
bus... the xchg could take a few cycles... but the question remains, how
frequently is printk called? Is it called "that often" that even 100
cycles can't be spared?


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