Messages in this thread | | | Date | Sun, 6 Aug 2000 02:10:46 +0100 | From | Philipp Rumpf <> | Subject | Re: test6-lowlatency-D1 results: 50msec + hangs .... |
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On Sat, Aug 05, 2000 at 05:52:26PM -0700, David S. Miller wrote: > Date: Sun, 6 Aug 2000 01:43:04 +0100 > From: Philipp Rumpf <prumpf@parcelfarce.linux.theplanet.co.uk> > > That's bogus on UP (spin_is_locked always returns 0). > > I think it would be reasonably nice to have something like > > spin_lock_held(spinlock_t *lock); > > that returns 1 for UP and spin_is_locked(lock) for SMP - basically > > Really, whatever you name it, the question of a lock being held or not > on UP has zero meaning. There is no correct return value, period.
Uhm, I disagree. "Am I holding this lock" is always true on UP. "Is someone else holding this lock" is always false. "Am I holding this lock" also isn't the same as spin_is_locked on SMP since you want to look at who's holding it when debugging is enabled. Same goes for "Is someone else holding this lock".
> No matter what constant answer you decide to give on UP it will always > be incorrect. I know, because there were old bits of assertions in
You're right. But no-one actually cares about whether a lock is held - they care about whether they're holding it or someone else is holding it or no-one's holding it.
Philipp
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