From: "Danilo Krummrich" <dakr@kernel.org>
To: "Christian König" <christian.koenig@amd.com>
Cc: <phasta@kernel.org>, "Sumit Semwal" <sumit.semwal@linaro.org>,
"Boris Brezillon" <boris.brezillon@collabora.com>,
"Alice Ryhl" <aliceryhl@google.com>,
"Daniel Almeida" <dwlsalmeida@gmail.com>,
"Gary Guo" <gary@garyguo.net>,
"Tvrtko Ursulin" <tvrtko.ursulin@igalia.com>,
<linux-media@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] dma-fence: Fix races of fence callbacks versus destructors by locking
Date: Mon, 08 Jun 2026 19:59:42 +0200 [thread overview]
Message-ID: <DJ3V3OCLIK2K.3CYKWYNHYU6JQ@kernel.org> (raw)
In-Reply-To: <9d49c901-fcdf-487a-a733-0320d0bdf94c@amd.com>
On Mon Jun 8, 2026 at 7:34 PM CEST, Christian König wrote:
> That's why we need the RCU grace period to make sure that nobody is
> referencing the driver stuff any more.
Right, and that's what Philipp tries to address, the requirement to wait for an
RCU grace period is perfectly fine if it is only about freeing memory, but it
can become painful if the fence private data contains data also needs to be
destructed in some way.
IOW, if a driver signals a fence, it is lifecycle-wise reasonable to destruct
the private data that is no longer needed (remaining users only deal with struct
dma_fence) and having to wait for a full grace period adds sublety and
complication that can be avoided with the proposed approach.
That said, I'd like to ask the opposite question: What are the concerns with the
proposed approach over (pure) RCU?
next prev parent reply other threads:[~2026-06-08 17:59 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-08 14:24 [RFC PATCH] dma-fence: Fix races of fence callbacks versus destructors by locking Philipp Stanner
2026-06-08 15:01 ` Boris Brezillon
2026-06-08 15:17 ` Philipp Stanner
2026-06-08 15:23 ` Danilo Krummrich
2026-06-08 15:30 ` Boris Brezillon
2026-06-08 15:30 ` Philipp Stanner
2026-06-08 16:16 ` Boris Brezillon
2026-06-09 8:02 ` Christian König
2026-06-09 8:54 ` Philipp Stanner
2026-06-09 8:43 ` Philipp Stanner
2026-06-09 8:47 ` Christian König
2026-06-09 9:00 ` Philipp Stanner
2026-06-08 15:07 ` Tvrtko Ursulin
2026-06-08 15:15 ` Philipp Stanner
2026-06-08 15:35 ` Christian König
2026-06-08 15:41 ` Philipp Stanner
2026-06-08 17:34 ` Christian König
2026-06-08 17:59 ` Danilo Krummrich [this message]
2026-06-08 18:32 ` Christian König
2026-06-08 18:39 ` Danilo Krummrich
2026-06-08 18:47 ` Christian König
2026-06-08 19:25 ` Danilo Krummrich
2026-06-09 8:17 ` Christian König
2026-06-09 5:52 ` Philipp Stanner
2026-06-09 10:26 ` Christian König
2026-06-09 10:42 ` Philipp Stanner
2026-06-09 10:53 ` Christian König
2026-06-09 11:39 ` Philipp Stanner
2026-06-09 13:19 ` Philipp Stanner
2026-06-09 13:34 ` Christian König
2026-06-10 14:25 ` Philipp Stanner
2026-06-10 15:15 ` Christian König
2026-06-11 8:35 ` Philipp Stanner
2026-06-11 9:14 ` Christian König
2026-06-11 9:50 ` Philipp Stanner
2026-06-11 11:06 ` Christian König
2026-06-09 13:36 ` Tvrtko Ursulin
2026-06-09 13:57 ` Philipp Stanner
2026-06-09 14:03 ` Christian König
2026-06-15 8:29 ` Properly synchronize dma_fence->signaled bit (Was: Re: [RFC PATCH] dma-fence: Fix races of fence callbacks versus destructors by locking) Philipp Stanner
2026-06-15 9:57 ` Christian König
2026-06-16 11:25 ` Philipp Stanner
2026-06-17 9:46 ` Christian König
2026-06-17 10:16 ` Philipp Stanner
2026-06-17 13:03 ` Christian König
2026-06-17 13:21 ` Philipp Stanner
2026-06-17 13:50 ` Gary Guo
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