Messages in this thread | | | Date | Wed, 21 Mar 2001 02:57:45 -0800 | From | george anzinger <> | Subject | Re: [PATCH for 2.5] preemptible kernel |
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"David S. Miller" wrote: > > Keith Owens writes: > > Or have I missed something? > > Nope, it is a fundamental problem with such kernel pre-emption > schemes. As a result, it would also break our big-reader locks > (see include/linux/brlock.h).
He has this one covered. The patch puts preemption locks around read_locks.
By the by, if a preemption lock is all that is needed the patch defines it and it is rather fast (an inc going in and a dec & test comming out). A lot faster than a spin lock with its "LOCK" access. A preempt lock does not need to be "LOCK"ed because the only contender is the same cpu.
George
> > Basically, anything which uses smp_processor_id() would need to > be holding some lock so as to not get pre-empted. > > Later, > David S. Miller > davem@redhat.com - 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/
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