Arjan van de Ven <[EMAIL PROTECTED]> wrote: > > 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) > > on x86 it makes a difference of maybe a few cycles. At most. > However please consider using spin_lock_irqsave(); the _irq() variant, > while it can be used correctly, is a major source of bugs since it > unconditionally enables interrupts on unlock. >
spin_lock_irq() is OK for down_*(), since down() can call schedule() anyway. spin_lock_irqsave() should be used in up_*() and I guess down_*_trylock(), although the latter shouldn't need to go into the slowpath anyway. - 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/
