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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?

    -Chris


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