From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 0E986601A8 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932537AbeFFIqo (ORCPT + 25 others); Wed, 6 Jun 2018 04:46:44 -0400 Received: from metis.ext.pengutronix.de ([85.220.165.71]:49107 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932423AbeFFIqm (ORCPT ); Wed, 6 Jun 2018 04:46:42 -0400 Message-ID: <1528274797.26063.6.camel@pengutronix.de> Subject: Re: [PATCH 1/3] drm/v3d: Take a lock across GPU scheduler job creation and queuing. From: Lucas Stach To: Eric Anholt , dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org Date: Wed, 06 Jun 2018 10:46:37 +0200 In-Reply-To: <20180605190302.18279-1-eric@anholt.net> References: <20180605190302.18279-1-eric@anholt.net> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.22.6-1+deb9u1 Mime-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2001:67c:670:100:fa0f:41ff:fe58:4010 X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Am Dienstag, den 05.06.2018, 12:03 -0700 schrieb Eric Anholt: > Between creation and queueing of a job, you need to prevent any other > job from being created and queued.  Otherwise the scheduler's fences > may be signaled out of seqno order. > > > Signed-off-by: Eric Anholt > Fixes: 57692c94dcbe ("drm/v3d: Introduce a new DRM driver for Broadcom V3D V3.x+") > --- > > ccing amd-gfx due to interaction of this series with the scheduler. > >  drivers/gpu/drm/v3d/v3d_drv.h |  5 +++++ >  drivers/gpu/drm/v3d/v3d_gem.c | 11 +++++++++-- >  2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h > index a043ac3aae98..26005abd9c5d 100644 > --- a/drivers/gpu/drm/v3d/v3d_drv.h > +++ b/drivers/gpu/drm/v3d/v3d_drv.h > @@ -85,6 +85,11 @@ struct v3d_dev { > >    */ > >   struct mutex reset_lock; >   > > + /* Lock taken when creating and pushing the GPU scheduler > > +  * jobs, to keep the sched-fence seqnos in order. > > +  */ > > + struct mutex sched_lock; > + > >   struct { > >   u32 num_allocated; > >   u32 pages_allocated; > diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c > index b513f9189caf..9ea83bdb9a30 100644 > --- a/drivers/gpu/drm/v3d/v3d_gem.c > +++ b/drivers/gpu/drm/v3d/v3d_gem.c > @@ -550,13 +550,16 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, > >   if (ret) > >   goto fail; >   > > + mutex_lock(&v3d->sched_lock); > >   if (exec->bin.start != exec->bin.end) { > >   ret = drm_sched_job_init(&exec->bin.base, > >    &v3d->queue[V3D_BIN].sched, > >    &v3d_priv->sched_entity[V3D_BIN], > >    v3d_priv); > > - if (ret) > > + if (ret) { > > + mutex_unlock(&v3d->sched_lock); >   goto fail_unreserve; I don't see any path where you would go to fail_unreserve with the mutex not yet locked, so you could just fold the mutex_unlock into this error path for a bit less code duplication. Otherwise this looks fine. Regards, Lucas > + } >   > >   exec->bin_done_fence = > >   dma_fence_get(&exec->bin.base.s_fence->finished); > @@ -570,12 +573,15 @@ v3d_submit_cl_ioctl(struct drm_device *dev, void *data, > >    &v3d->queue[V3D_RENDER].sched, > >    &v3d_priv->sched_entity[V3D_RENDER], > >    v3d_priv); > > - if (ret) > > + if (ret) { > > + mutex_unlock(&v3d->sched_lock); > >   goto fail_unreserve; > > + } >   > >   kref_get(&exec->refcount); /* put by scheduler job completion */ > >   drm_sched_entity_push_job(&exec->render.base, > >     &v3d_priv->sched_entity[V3D_RENDER]); > > + mutex_unlock(&v3d->sched_lock); >   > >   v3d_attach_object_fences(exec); >   > @@ -615,6 +621,7 @@ v3d_gem_init(struct drm_device *dev) > >   spin_lock_init(&v3d->job_lock); > >   mutex_init(&v3d->bo_lock); > >   mutex_init(&v3d->reset_lock); > > + mutex_init(&v3d->sched_lock); >   > >   /* Note: We don't allocate address 0.  Various bits of HW > >    * treat 0 as special, such as the occlusion query counters