Re: [PATCH 2/2 v6] locking/selftest: Support queued rwlock

From: Waiman Long <waiman.long@hp.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	Maarten Lankhorst <maarten.lankhorst@canonical.com>,
	Rik van Riel <riel@redhat.com>,
	linux-kernel@vger.kernel.org,
	Scott J Norton <scott.norton@hp.com>,
	Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [PATCH 2/2 v6] locking/selftest: Support queued rwlock
Date: Wed, 06 Aug 2014 13:24:36 -0400	[thread overview]
Message-ID: <53E264D4.5090800@hp.com> (raw)
In-Reply-To: <20140805132837.GA19379@twins.programming.kicks-ass.net>

On 08/05/2014 09:28 AM, Peter Zijlstra wrote:
> On Tue, Jul 29, 2014 at 02:53:19PM -0400, Waiman Long wrote:
>> The queued rwlock does not support the use of recursive read-lock in
>> the process context. With changes in the lockdep code to check and
>> disallow recursive read-lock, it is also necessary for the locking
>> selftest to be updated to change the process context recursive read
>> locking results from SUCCESS to FAILURE for rwlock.
>>
> Maybe I wasn't clear; but I meant you should extend the lock tests to
> cover the full qrwlock semantics.
>
> That means we also need tests like:
>
> 	RL(X1);
> 	IRQ_ENTER();
> 	RL(X2);
> 	IRQ_EXIT();
>
> To fully validate that in_interrupt exception to fairness etc..

Sorry for misinterpretation. I have just sent out an updated patch with 
additional self tests to verify that recursive read-lock is allowed 
under interrupt context.

-Longman