Re: [PATCH 1/1] lockdep: Kill held_lock->check and "int check" argof __lock_acquire()

[Oleg Nesterov]

On 01/13, Peter Zijlstra wrote:
>
> On Mon, Jan 13, 2014 at 06:06:09PM +0100, Oleg Nesterov wrote:
> >
> > And I just realized that rcu_lock_acquire() does lock_acquire(check => 1).
> > Probably we can mark rcu_lock_map's as __lockdep_no_validate__.
>
> Can't, RCU needs its own classes. Otherwise it cannot tell which version
> of the RCU read lock its holding at just that moment.

Ah, indeed. Thanks.

Can't it do lock_acquire(trylock => 1, read => 2) ? this still means
mark_irqflags(), but perhaps this won't hurt too much.

> At the very least we can reduce check to a single bit.

Or this, yes.

Oleg.

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