Here's "PATCH #3", that basically counts recursive printk entries and
printks the number of failed printks upon the next successful printk...
Please, let me know if it helps!
-Chris
On Tue, 4 Jul 2000, Roger Larsson wrote:
> Hi,
>
> But WHERE is the patch?
> (I like to try it with my latency-profiling patch)
>
> /RogerL
>
> Chris Lattner wrote:
> >
> > Okay, try two. :)
> >
> > I don't think that completely redesigning the console before 2.4 goes out
> > is such a good idea... so here is a much smaller fix that also happens to
> > fix my previous oversight (yeeeouch! :).
> >
> > Basically, printk needs to be locked more finely... there is no reason in
> > the world for the console lock to protect "buf" in addition to all the
> > console stuff... so this patch adds protection to buf, moves buf into
> > printk (as a static array), AND allows _SAFE_ recursion by kmalloc'ing a
> > new buffer if "buf" is in use.
> >
> > This should reduce some console latency by making the console lock unheld
> > for the vsprintf but held for the real console stuff... This patch keeps
> > the common case nearly identical in performance: it only does a kmalloc
> > during the extremely unlikely cases that are not handled now... [okay, I
> > guess deadlock is "handling" it... but... :]
> >
> > Personally, I didn't like the idea of having one "buf" per proc, because
> > it doesn't fix the recursion problem, it expands the needed data space
> > (albeit not by much), and (if that approach were to be allied more
> > generally) would bloat the kernel by a lot. The one thing it had going
> > for it was the fact that you could be vsprintf'ing in parrellel! :)
> >
> > Anyways, let me know if I did something stupid again. :)
> >
> > -Chris
> >
> > -
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
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> > Please read the FAQ at http://www.tux.org/lkml/
>
> --
> Home page:
> http://www.norran.net/nra02596/
>
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