Re: [PATCH] SLUB use cmpxchg_local

Christoph Lameter
2007-08-27T21:04:18Z

I think the simplest solution may be to leave slub as done in the patch
that we developed last week. The arch must provide a cmpxchg_local that is
performance wise the fastest possible. On x86 this is going to be the
cmpxchg_local on others where cmpxchg is slower than interrupt
disable/enable this is going to be the emulation that does

interrupt disable

cmpchg simulation

interrupt enable

If we can establish that this is not a performance regression then we have
a clean solution source code wise. It also minimizes the interrupt holdoff
for the non-cmpxchg_local arches. However, it means that we will have to
disable interrupts twice for the slow path. If that is too expensive then
we need a different solution.