* Christoph Hellwig <[EMAIL PROTECTED]> wrote: > On Tue, Jul 19, 2005 at 02:34:57PM +0200, Ingo Molnar wrote: > > (I do disagree with Christoph on another point: i do think we eventually > > want to change the standard semaphore type in a similar fashion upstream > > as well - but that probably has to come with a s/struct semaphore/struct > > mutex/ change as well.) > > Actually having a mutex_t in mainline would be a good idea even > without preempt rt, to document better what kind of locking we expect.
cool! I'll cook up a patch for that. Right now these are the numbers: there are 526 uses of struct semaphore in 2.6.12. In the -RT tree i had to change 23 of them to be compat_semaphore - i.e. 23 uses were definitely non-mutex. (We sure have missed some cases - but it would be fair to say that the expected number of cases is less than 50, and that we've mapped the most common ones already. That makes it a 90%/10% splitup: more than 90% of all struct semaphore use is pure mutex.) Of the remaining <10% cases, the majority is of the type of completions, and there are a handful of (<10) cases of 'counted semaphore' uses: semaphores with a count larger than 1. (e.g. ACPI uses it to count resources, some audio code too - but it's very rare) Btw., that's the only 'true' (in terms of CS) semaphore use. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/