From patchwork Wed Mar 5 13:05:50 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philipp Stanner X-Patchwork-Id: 14002600 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 61949C282EC for ; Wed, 5 Mar 2025 13:06:07 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DDA0510E0E5; Wed, 5 Mar 2025 13:06:06 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="oSAr/Q0p"; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0B14A10E0E5 for ; Wed, 5 Mar 2025 13:06:06 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id A21805C68E6; Wed, 5 Mar 2025 13:03:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7BABBC4CEEA; Wed, 5 Mar 2025 13:06:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1741179965; bh=s9ST4+emcIcU6IvxekHRjVJTnRB1rgArxQeZs5dv/lA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oSAr/Q0pBfAR1NOqM9X7y8gIvBFuKdF4nPTlJcNTbHzobtgmuEOwOi/ppny0+5l9g VDVrQhHvm9iN1eJlJAGBKXuJ/eLHRBXzPCurdzfB1kl3KmsqaiCFahOr4crecf77jd 61l9tvUQtuzrWKA1bCa9sFKYdKGal8dT2HnZIeLn/SrqalHOTOzjPhDHjv+36INNWR rJ2omCO271m+vNjC2MNAKGFuf10tECiMqhyoFd5Pns+Z8K5kRuttp40Fw/OfexdNc8 /mAXeCzV14QDbWJuh32SXahw9muHUS85lqHURNrh9ppSeS14zwEqfHKMyrwLfxGmWL Bx7gUkfPIG43A== From: Philipp Stanner To: Matthew Brost , Danilo Krummrich , Philipp Stanner , =?utf-8?q?Christian_K=C3=B6nig?= , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Sumit Semwal Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 1/3] drm/sched: Adjust outdated docu for run_job() Date: Wed, 5 Mar 2025 14:05:50 +0100 Message-ID: <20250305130551.136682-3-phasta@kernel.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250305130551.136682-2-phasta@kernel.org> References: <20250305130551.136682-2-phasta@kernel.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The documentation for drm_sched_backend_ops.run_job() mentions a certain function called drm_sched_job_recovery(). This function does not exist. What's actually meant is drm_sched_resubmit_jobs(), which is by now also deprecated. Furthermore, the scheduler expects to "inherit" a reference on the fence from the run_job() callback. This, so far, is also not documented. Remove the mention of the removed function. Discourage the behavior of drm_sched_backend_ops.run_job() being called multiple times for the same job. Document the necessity of incrementing the refcount in run_job(). Signed-off-by: Philipp Stanner --- include/drm/gpu_scheduler.h | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-) diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h index 50928a7ae98e..6381baae8024 100644 --- a/include/drm/gpu_scheduler.h +++ b/include/drm/gpu_scheduler.h @@ -410,10 +410,36 @@ struct drm_sched_backend_ops { struct drm_sched_entity *s_entity); /** - * @run_job: Called to execute the job once all of the dependencies - * have been resolved. This may be called multiple times, if - * timedout_job() has happened and drm_sched_job_recovery() - * decides to try it again. + * @run_job: Called to execute the job once all of the dependencies + * have been resolved. + * + * @sched_job: the job to run + * + * The deprecated drm_sched_resubmit_jobs() (called by &struct + * drm_sched_backend_ops.timedout_job) can invoke this again with the + * same parameters. Using this is discouraged because it violates + * dma_fence rules, notably dma_fence_init() has to be called on + * already initialized fences for a second time. Moreover, this is + * dangerous because attempts to allocate memory might deadlock with + * memory management code waiting for the reset to complete. + * + * TODO: Document what drivers should do / use instead. + * + * This method is called in a workqueue context - either from the + * submit_wq the driver passed through drm_sched_init(), or, if the + * driver passed NULL, a separate, ordered workqueue the scheduler + * allocated. + * + * Note that the scheduler expects to 'inherit' its own reference to + * this fence from the callback. It does not invoke an extra + * dma_fence_get() on it. Consequently, this callback must take a + * reference for the scheduler, and additional ones for the driver's + * respective needs. + * + * Return: + * * On success: dma_fence the driver must signal once the hardware has + * completed the job ("hardware fence"). + * * On failure: NULL or an ERR_PTR. */ struct dma_fence *(*run_job)(struct drm_sched_job *sched_job);