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Date: Wed, 07 Jan 2026 15:08:06 +0100
Message-Id: <DFIEZJJK8GUD.1XW0UQSIUCH2N@kernel.org>
Subject: Re: [PATCH] drm/sched: Simplify idle entity check
Cc: <dri-devel@lists.freedesktop.org>, <kernel-dev@igalia.com>,
 <intel-xe@lists.freedesktop.org>, =?utf-8?q?Christian_K=C3=B6nig?=
 <christian.koenig@amd.com>, "Matthew Brost" <matthew.brost@intel.com>,
 "Philipp Stanner" <phasta@kernel.org>
To: "Tvrtko Ursulin" <tvrtko.ursulin@igalia.com>
From: "Danilo Krummrich" <dakr@kernel.org>
References: <20260107134405.96603-1-tvrtko.ursulin@igalia.com>
In-Reply-To: <20260107134405.96603-1-tvrtko.ursulin@igalia.com>
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On Wed Jan 7, 2026 at 2:44 PM CET, Tvrtko Ursulin wrote:
> While at it, we add READ_ONCE annotation on the entity->stopped check to
> mark the unlocked read.

READ_ONCE() is not about marking unlocked reads and does not guarantee
atomicity.

Instead, it is about compiler control, i.e. forcing loads, and, depending o=
n the
architecture, deal with address and control dependency barriers.

If we want lockless access to entity->stopped it should be atomic_read(),
atomic_read_acquire(), etc.

- Danilo