On Tue, 2007-10-30 at 07:07 +1100, Benjamin Herrenschmidt wrote: > On Mon, 2007-10-29 at 11:50 -0700, Paul E. McKenney wrote: > > Hello! > > > > A few random patches that permit POWER to pass kernbench on -rt. > > Many of these have more focus on expediency than care for correctness, > > so might best be thought of as workarounds than as complete solutions. > > There are still issues not addressed by this patch, including: > > > > o kmem_cache_alloc() from non-preemptible context during > > bootup (xics_startup() building the irq_radix_revmap()). > > > > o unmap_vmas() freeing pages with preemption disabled. > > Might be able to address this by linking the pages together, > > then freeing them en masse after preemption has been re-enabled, > > but there is likely a better approach. > > > > Thoughts? > > I see a lot of case where you add preempt_disable/enable around areas > that have the PTE lock held... > > So in -rt, spin_lock doesn't disable preempt ? I'm a bit worried...
So as Paul mentioned, spin_lock is now a mutex. There is a new raw_spinlock however (simply change the way it is declared, calling conventions are the same) which is used in a very few areas where a traditional spin_lock is truly necessary. This may or may not be one of those times, but I wanted to point it out. --Darren > there are some strong requirements that anything within that lock is not > preempted, so zap_pte_ranges() is the obvious ones but all of them would > need to be addressed. > > Ben. > > - 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/
