Messages in this thread | | | Date | Thu, 12 Nov 2015 20:33:02 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 4/4] locking: Introduce smp_cond_acquire() |
| |
On 11/12, Peter Zijlstra wrote: > > On Thu, Nov 12, 2015 at 07:38:07PM +0100, Oleg Nesterov wrote: > > It seems that PPC needs to define smp_mb__before_spinlock() as full mb(), > > no? > > It does: > > arch/powerpc/include/asm/barrier.h:#define smp_mb__before_spinlock() smp_mb()
Ah, indeed, thanks.
And given that it also defines smp_mb__after_unlock_lock() as smp_mb(), I am starting to understand how it can help to avoid the races with spin_unlock_wait() in (for example) do_exit().
But as Boqun has already mentioned, this means that mb__after_unlock_lock() has the new meaning which should be documented.
Hmm. And 12d560f4 "Privatize smp_mb__after_unlock_lock()" should be reverted then ;)
Oleg.
| |