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From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Hellstrom <thellstrom@vmware.com>
Cc: Matthew Wilcox <willy@infradead.org>,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	Ingo Molnar <mingo@redhat.com>, Jonathan Corbet <corbet@lwn.net>,
	Gustavo Padovan <gustavo@padovan.org>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Sean Paul <seanpaul@chromium.org>,
	David Airlie <airlied@linux.ie>,
	Davidlohr Bueso <dave@stgolabs.net>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	Philippe Ombredanne <pombredanne@nexb.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-doc@vger.kernel.org, linux-media@vger.kernel.org,
	linaro-mm-sig@lists.linaro.org
Subject: Re: [PATCH v2 1/2] locking: Implement an algorithm choice for Wound-Wait mutexes
Date: Thu, 14 Jun 2018 16:46:59 +0200	[thread overview]
Message-ID: <20180614144659.GC12198@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <425f4d5b-d414-de46-f388-55f1e6821ba6@vmware.com>

On Thu, Jun 14, 2018 at 03:43:04PM +0200, Thomas Hellstrom wrote:
> It's intended to be enforced by storing the algorithm choice in the
> WW_MUTEX_CLASS which must be common for an acquire context and the
> ww_mutexes it acquires. However, I don't think there is a check that that
> holds. I guess we could add it as a DEBUG_MUTEX test in ww_mutex_lock().

There is ww_mutex_lock_acquired():

	DEBUG_LOCKS_WARN_ON(ww_ctx->ww_class != ww->ww_class)

which should trigger if you try and be clever.

  reply	other threads:[~2018-06-14 14:47 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-14  7:29 [PATCH v2 0/2] locking,drm: Fix ww mutex naming / algorithm inconsistency Thomas Hellstrom
2018-06-14  7:29 ` [PATCH v2 1/2] locking: Implement an algorithm choice for Wound-Wait mutexes Thomas Hellstrom
2018-06-14 10:38   ` Andrea Parri
2018-06-14 11:10     ` Thomas Hellstrom
2018-06-14 11:49       ` Andrea Parri
2018-06-14 12:04         ` Thomas Hellstrom
2018-06-14 12:08         ` Thomas Hellstrom
2018-06-14 11:36   ` Peter Zijlstra
2018-06-14 11:54     ` Thomas Hellstrom
2018-06-14 13:29       ` Matthew Wilcox
2018-06-14 13:43         ` Thomas Hellstrom
2018-06-14 14:46           ` Peter Zijlstra [this message]
2018-06-14 12:41   ` Peter Zijlstra
2018-06-14 12:48     ` Thomas Hellstrom
2018-06-14 13:18       ` Thomas Hellstrom
2018-06-14  7:29 ` [PATCH v2 2/2] drm: Change deadlock-avoidance algorithm for the modeset locks Thomas Hellstrom

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