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 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 1ACE8EB64D8 for ; Wed, 21 Jun 2023 14:53:38 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D25E910E4A0; Wed, 21 Jun 2023 14:53:36 +0000 (UTC) Received: from madras.collabora.co.uk (madras.collabora.co.uk [46.235.227.172]) by gabe.freedesktop.org (Postfix) with ESMTPS id B408810E49E for ; Wed, 21 Jun 2023 14:53:34 +0000 (UTC) Received: from localhost (unknown [IPv6:2a01:e0a:2c:6930:5cf4:84a1:2763:fe0d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by madras.collabora.co.uk (Postfix) with ESMTPSA id 07E0A6606F95; Wed, 21 Jun 2023 15:53:33 +0100 (BST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1687359213; bh=3qWmWajxAtJ1rjuJPxbMRSUA56lMgLxV8O0kOyRxVyc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=d3WlqNHH6URd0+xfB4SaJWwVaKFiNIetnoJxK6Wv2IO59I/JtVHpirn+02haTlBQw RooofN0BWvemTZpV/jcx8RZ6+fhPY+VGtZkjjxH2bVM2bz8GyWK+odXwAE+A0pTh6A oM++ZbzX0AVYns8iPFlDPeoZA0lzcamxmL9Ajfnp9rZHVp1zlWIeZ/K4htuBZmX5BR ljFIQfcgBrn5vDTPXeRyCA+9+WyIBniIByHFTP4APGewtjB+7a7lEOWs5LubkAZNZA 2MmoonsAVWPnR1k3yrWjxhfZvmQhCt3qqNKte7CEGwir8bel2YT8gJAHfDKNWGtXm8 Xd+vEbLKjEPGw== Date: Wed, 21 Jun 2023 16:53:30 +0200 From: Boris Brezillon To: Luben Tuikov Subject: Re: [PATCH v6] drm/sched: Make sure we wait for all dependencies in kill_jobs_cb() Message-ID: <20230621165330.29870beb@collabora.com> In-Reply-To: <3d269410-e9ee-6cf5-8c22-5fb916ff75b2@amd.com> References: <20230619071921.3465992-1-boris.brezillon@collabora.com> <20230621161808.24262cdd@collabora.com> <3d269410-e9ee-6cf5-8c22-5fb916ff75b2@amd.com> Organization: Collabora X-Mailer: Claws Mail 4.1.1 (GTK 3.24.37; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable 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: , Cc: Sarah Walker , dri-devel@lists.freedesktop.org, Sumit Semwal , Donald Robson , Christian =?UTF-8?B?S8O2bmln?= Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Wed, 21 Jun 2023 10:41:22 -0400 Luben Tuikov wrote: > On 2023-06-21 10:18, Boris Brezillon wrote: > > Hello Luben, > >=20 > > On Wed, 21 Jun 2023 09:56:40 -0400 > > Luben Tuikov wrote: > > =20 > >> On 2023-06-19 03:19, Boris Brezillon wrote: =20 > >>> drm_sched_entity_kill_jobs_cb() logic is omitting the last fence popp= ed > >>> from the dependency array that was waited upon before > >>> drm_sched_entity_kill() was called (drm_sched_entity::dependency fiel= d), > >>> so we're basically waiting for all dependencies except one. > >>> > >>> In theory, this wait shouldn't be needed because resources should have > >>> their users registered to the dma_resv object, thus guaranteeing that > >>> future jobs wanting to access these resources wait on all the previous > >>> users (depending on the access type, of course). But we want to keep > >>> these explicit waits in the kill entity path just in case. > >>> > >>> Let's make sure we keep all dependencies in the array in > >>> drm_sched_job_dependency(), so we can iterate over the array and wait > >>> in drm_sched_entity_kill_jobs_cb(). > >>> > >>> We also make sure we wait on drm_sched_fence::finished if we were > >>> originally asked to wait on drm_sched_fence::scheduled. In that case, > >>> we assume the intent was to delegate the wait to the firmware/GPU or > >>> rely on the pipelining done at the entity/scheduler level, but when > >>> killing jobs, we really want to wait for completion not just scheduli= ng. > >>> > >>> v6: > >>> - Back to v4 implementation > >>> - Add Christian's R-b > >>> > >>> v5: > >>> - Flag deps on which we should only wait for the scheduled event > >>> at insertion time > >>> > >>> v4: > >>> - Fix commit message > >>> - Fix a use-after-free bug > >>> > >>> v3: > >>> - Always wait for drm_sched_fence::finished fences in > >>> drm_sched_entity_kill_jobs_cb() when we see a sched_fence > >>> > >>> v2: > >>> - Don't evict deps in drm_sched_job_dependency() =20 > >> > >> Hmm, why is this in reverse chronological order? > >> It's very confusing. =20 > >=20 > > Dunno, that's how I've always ordered things, and quick look at some > > dri-devel patches [1][2] makes me think I'm not the only one to start > > from the latest submission. > >=20 > > [1]https://lkml.org/lkml/2023/6/19/941 > > [2]https://lore.kernel.org/dri-devel/cover.1686729444.git.Sandor.yu@nxp= .com/T/#t > > =20 > >> =20 > >>> > >>> Signed-off-by: Boris Brezillon > >>> Suggested-by: "Christian K=C3=B6nig" > >>> Reviewed-by: "Christian K=C3=B6nig" =20 > >> > >> These three lines would usually come after the CCs. =20 > >=20 > > Again, I think I've always inserted those tags before the Cc, but I can > > re-order things if you prefer. Let me know if you want me to send a v7 > > addressing the Cc+changelog ordering. =20 >=20 > No, it's not necessary for this patch, but in the future I'd rather follow > chronological ordering for the versions, and in the Cc list. It's similar > to how the patch description follows (narrative text) and to how we reply > back to emails, and prevalently in the kernel log in drm ("git log" should > suffice). >=20 > Reading in chronological progression builds a narrative, a picture, in on= e's > mind and makes it easy to see justifications for said narrative, or see r= easons > to change the narrative. >=20 > That is, one can make a better decision knowing the full history, rather = than > only the latest change. >=20 > (And in fact when I read the version revision list, my eyes skip over v[X] > and just read down, so I was wondering why and how Christian R-B the patch > in v2, and it wasn't until I actually saw that they were ordered in rever= se > chronological order, which was in fact v6--listed first, which I'd assumed > was listed last.) >=20 > Do you have access or do you know who is pushing this patch to drm-misc-f= ixes? I can push it.