Re: [PATCH] SLUB use cmpxchg_local

Peter Zijlstra
2007-08-28T07:13:03Z

On Mon, 2007-08-27 at 15:15 -0700, Christoph Lameter wrote:
> Hmmmm. One wild idea would be to use a priority futex for the slab lock?
> That would make the slow paths interrupt safe without requiring interrupt
> disable? Does a futex fit into the page struct?

Very much puzzled at what you propose. in-kernel we use rt_mutex (has
PI) or mutex, futexes are user-space. (on -rt spinlock_t == mutex ==
rt_mutex)

Neither disable interrupts since they are sleeping locks.

That said, on -rt we do not need to disable interrupts in the allocators
because its a bug to call an allocator from raw irq context.