Arjan van de Ven <[EMAIL PROTECTED]> writes: > On Wed, 2005-03-09 at 16:34 +0530, Suparna Bhattacharya wrote: >> Any sense of how costly it is to use spin_lock_irq's vs spin_lock >> (across different architectures) ? Isn't rwsem used very widely ? > > oh also rwsems aren't used all that much simply because they are quite > more expensive than regular semaphores, so that you need a HUGE bias in > reader/writer ratio to make it even worth it...
I agree. I think in fact once Christopher L's lockless page fault fast path goes in it would be a good idea to reevaluate if mmap_sem should be really a rwsem and possibly change it back to a normal semaphore that perhaps gets dropped only on a page cache miss. -Andi - 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/
