On Thursday 15 November 2007 19:17, David Brownell wrote: > On Wednesday 14 November 2007, Nick Piggin wrote: > > > > > All this does is prevent constant and needless checking for > > > > > "do you want to preempt me now?" "now?" "now?" in "now?" the > > > > > middle "now?" of "now?" i/o "now?" loops. > > > > > > > > Actually that's wrong. > > > > > > Certainly it's right for the mainstream kernel. Dropping a > > > lock (other than a raw spinlock) does that checking; when a > > > loop needs to acquire then drop such a lock, that's exactly > > > what's going on. > > > > Obviously a raw spinlock is no different from a regular > > spinlock upstream. > > Erm, no. The raw ones don't have the extra logic when > the lock gets dropped.
If you don't have preemption disabled already, then it is a bug to use raw spinlocks. If you do have preemption disabled, then a regular spinlock isn't going to check preemption after the unlock either. - 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/
