From mboxrd@z Thu Jan 1 00:00:00 1970 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E1229C433EF for ; Tue, 12 Apr 2022 18:20:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1357656AbiDLSW4 (ORCPT ); Tue, 12 Apr 2022 14:22:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54216 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236948AbiDLSWx (ORCPT ); Tue, 12 Apr 2022 14:22:53 -0400 Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2C0DB4969F for ; Tue, 12 Apr 2022 11:20:35 -0700 (PDT) Received: from [IPV6:2a00:5f00:102:0:10b3:10ff:fe5d:4ec1] (unknown [IPv6:2a00:5f00:102:0:10b3:10ff:fe5d:4ec1]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: dmitry.osipenko) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id AD94E1F44A65; Tue, 12 Apr 2022 19:20:32 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1649787633; bh=89nEyLETtUj6qse1DGp0rsGFjY9owVYpHqNxsQzbbW4=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=QDGr51ksXmI4Pez4M+ze9AcF+g/sAdJ+SZL2gaA3ylgszoig0/IJrP9uj05T9dIT0 MwFBfhb3F5TPRfV3ObzCq+OInxq4oPo5sjvB81gxcIiz0r/5Z0DzndxXHgxu9F7Gew 5W3k7l7L1GMN4OoJM3a8pnfsfIGdAiK7gY2TZJPObBj6sfPU20AWjRfw+BJHjTY2GA GT953VvXgw61UZPXPW2Kp7qmrx49cXR9G6gpk0FDQDQr5AX4nmzJrDcgEd2cGY26TS xMT4x+/yxUrqrJ838NWNOVRs4f3B2XFIGaJtPS6tnm4iTn1jjf6rnK2GmtbCFe+Aam oy/edFnVBz7tg== Message-ID: Date: Tue, 12 Apr 2022 21:20:29 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.7.0 Subject: Re: [PATCH v1] drm/scheduler: Don't kill jobs in interrupt context Content-Language: en-US To: Andrey Grodzovsky , David Airlie , Daniel Vetter , Tomeu Vizoso , Steven Price , Rob Herring , Alyssa Rosenzweig , Rob Clark Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Dmitry Osipenko References: <20220411221536.283312-1-dmitry.osipenko@collabora.com> <064d8958-a288-64e1-b2a4-c2302a456d5b@amd.com> From: Dmitry Osipenko In-Reply-To: <064d8958-a288-64e1-b2a4-c2302a456d5b@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/12/22 19:51, Andrey Grodzovsky wrote: > > On 2022-04-11 18:15, Dmitry Osipenko wrote: >> Interrupt context can't sleep. Drivers like Panfrost and MSM are taking >> mutex when job is released, and thus, that code can sleep. This results >> into "BUG: scheduling while atomic" if locks are contented while job is >> freed. There is no good reason for releasing scheduler's jobs in IRQ >> context, hence use normal context to fix the trouble. > > > I am not sure this is the beast Idea to leave job's sw fence signalling > to be > executed in system_wq context which is prone to delays of executing > various work items from around the system. Seems better to me to leave the > fence signaling within the IRQ context and offload only the job freeing or, > maybe handle rescheduling to thread context within drivers implemention > of .free_job cb. Not really sure which is the better. We're talking here about killing jobs when driver destroys context, which doesn't feel like it needs to be a fast path. I could move the signalling into drm_sched_entity_kill_jobs_cb() and use unbound wq, but do we really need this for a slow path?