Alan Cox wrote:
>
> > > In eepro100.c, wait_for_cmd_done() can busywait for one millisecond
> > > and is called multiple times under spinlock.
> >
> > Did I get that right, as long as spinlocked no sense in
> > conditional_schedule()
>
> No conditional schedule, no pre-emption. You would need to rewrite that
> code to do something like try for 100uS then queue a 1 tick timer to
> retry asynchronously. That makes the code vastly more complex for an
> error case and for some drivers where irq mask is required during reset
> waits won't help.
That wait_for_cmd_done() and similar functions in other drivers are called
let's say 3 times in interrupt handler or spinlocked routine and 20 times in
non-interrupts disabled nor spinlocked functions.
Spinlocked reqions are usually protected by spin_lock_irqsave().
So the code reads
if (!spin_is_locked(sl))
conditional_schedule();
This doesn't make the whole problem go away, but could make the situation a
little bit better for most of the time?
- Jussi Laako
-- PGP key fingerprint: 161D 6FED 6A92 39E2 EB5B 39DD A4DE 63EB C216 1E4B Available at PGP keyservers- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue Jan 15 2002 - 21:00:48 EST