Re: [RFC][PATCH 4/7] lockdep: Seperate lock ids for read/writeacquires

From: Steven Rostedt
Date: Mon Apr 18 2011 - 13:33:33 EST


On Mon, 2011-04-18 at 18:49 +0200, Peter Zijlstra wrote:
> On Mon, 2011-04-18 at 12:46 -0400, Steven Rostedt wrote:
>
> > > void lockdep_off(void)
> > > @@ -1988,6 +1988,9 @@ static void check_chain_key(struct task_
> > > if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
> > > return;
> > >
> > > + if (is_read(hlock->rw_state))
> > > + id += MAX_LOCKDEP_KEYS;
> >
> > Again, isn't this about recursive reads? Or am I just confused ;)
>
> So what we do here is split off the write chain, the above could have
> been writeen if (!is_write()) to clarify that.

Or just add a comment ;)

-- Steve

>
> Everything except recursive read validation will traverse both chains,
> the recursive read validation will only traverse the write chains and
> ignore the combined read/recursive-read chain.


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