From: Gerd Hoffmann <kraxel@redhat.com>
To: Chia-I Wu <olvaffe@gmail.com>
Cc: ML dri-devel <dri-devel@lists.freedesktop.org>,
Gurchetan Singh <gurchetansingh@chromium.org>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
"open list:VIRTIO GPU DRIVER"
<virtualization@lists.linux-foundation.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 06/18] drm/virtio: remove ttm calls from in virtio_gpu_object_{reserve,unreserve}
Date: Fri, 5 Jul 2019 10:53:25 +0200 [thread overview]
Message-ID: <20190705085325.am2reucblvxc6qpg@sirius.home.kraxel.org> (raw)
In-Reply-To: <CAPaKu7S4Og7kda2ZjFtuRv=_W8gpFbD5y7s==0JB5Z34S4Hsjw@mail.gmail.com>
On Thu, Jul 04, 2019 at 12:17:48PM -0700, Chia-I Wu wrote:
> On Thu, Jul 4, 2019 at 4:10 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
> >
> > Hi,
> >
> > > > - r = ttm_bo_reserve(&bo->tbo, true, false, NULL);
> > > > + r = reservation_object_lock_interruptible(bo->gem_base.resv, NULL);
> > > Can you elaborate a bit about how TTM keeps the BOs alive in, for
> > > example, virtio_gpu_transfer_from_host_ioctl? In that function, only
> > > three TTM functions are called: ttm_bo_reserve, ttm_bo_validate, and
> > > ttm_bo_unreserve. I am curious how they keep the BO alive.
> >
> > It can't go away between reserve and unreserve, and I think it also
> > can't be evicted then. Havn't checked how ttm implements that.
> Hm, but the vbuf using the BO outlives the reserve/unreserve section.
> The NO_EVICT flag applies only when the BO is still alive. Someone
> needs to hold a reference to the BO to keep it alive, otherwise the BO
> can go away before the vbuf is retired.
Note that patches 14+15 rework virtio_gpu_transfer_*_ioctl to keep
gem reference until the command is finished and patch 17 drops
virtio_gpu_object_{reserve,unreserve} altogether.
Maybe I should try to reorder the series, then squash 6+17 to reduce
confusion. I suspect that'll cause quite a few conflicts though ...
cheers,
Gerd
next prev parent reply other threads:[~2019-07-05 8:53 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190702141903.1131-1-kraxel@redhat.com>
2019-07-02 14:18 ` [PATCH v6 01/18] drm/virtio: pass gem reservation object to ttm init Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 02/18] drm/virtio: switch virtio_gpu_wait_ioctl() to gem helper Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 03/18] drm/virtio: simplify cursor updates Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 04/18] drm/virtio: remove virtio_gpu_object_wait Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 05/18] drm/virtio: drop no_wait argument from virtio_gpu_object_reserve Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 06/18] drm/virtio: remove ttm calls from in virtio_gpu_object_{reserve,unreserve} Gerd Hoffmann
2019-07-03 18:02 ` Chia-I Wu
2019-07-04 11:10 ` Gerd Hoffmann
2019-07-04 19:17 ` Chia-I Wu
2019-07-05 8:53 ` Gerd Hoffmann [this message]
2019-07-07 5:30 ` Chia-I Wu
2019-07-02 14:18 ` [PATCH v6 07/18] drm/virtio: add virtio_gpu_object_array & helpers Gerd Hoffmann
2019-07-03 18:31 ` Chia-I Wu
2019-07-03 19:52 ` Chia-I Wu
2019-07-04 11:19 ` Gerd Hoffmann
2019-07-04 11:11 ` Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 08/18] drm/virtio: rework virtio_gpu_execbuffer_ioctl fencing Gerd Hoffmann
2019-07-03 18:49 ` Chia-I Wu
2019-07-04 11:25 ` Gerd Hoffmann
2019-07-04 18:46 ` Chia-I Wu
2019-07-11 2:35 ` Chia-I Wu
2019-07-02 14:18 ` [PATCH v6 09/18] drm/virtio: rework virtio_gpu_object_create fencing Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 10/18] drm/virtio: drop virtio_gpu_object_list_validate/virtio_gpu_unref_list Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 11/18] drm/virtio: switch from ttm to gem shmem helpers Gerd Hoffmann
2019-07-04 13:33 ` Emil Velikov
2019-07-17 6:04 ` Chia-I Wu
2019-07-02 14:18 ` [PATCH v6 12/18] drm/virtio: remove virtio_gpu_alloc_object Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 13/18] drm/virtio: drop virtio_gpu_object_{ref,unref} Gerd Hoffmann
2019-07-02 14:18 ` [PATCH v6 14/18] drm/virtio: rework virtio_gpu_transfer_from_host_ioctl fencing Gerd Hoffmann
2019-07-03 20:05 ` Chia-I Wu
2019-07-04 11:47 ` Gerd Hoffmann
2019-07-04 18:55 ` Chia-I Wu
2019-07-05 9:01 ` Gerd Hoffmann
2019-07-02 14:19 ` [PATCH v6 15/18] drm/virtio: rework virtio_gpu_transfer_to_host_ioctl fencing Gerd Hoffmann
2019-07-03 19:55 ` Chia-I Wu
2019-07-04 11:51 ` Gerd Hoffmann
2019-07-04 19:08 ` Chia-I Wu
2019-07-05 9:05 ` Gerd Hoffmann
2019-07-05 14:07 ` Gerd Hoffmann
2019-07-02 14:19 ` [PATCH v6 16/18] drm/virtio: rework virtio_gpu_cmd_context_{attach,detach}_resource Gerd Hoffmann
[not found] ` <CAAfnVBmKotCfkrM4hph4++FDrVUYR8WKpomP7Y0-aergqHTSyA@mail.gmail.com>
2019-07-04 12:00 ` Gerd Hoffmann
2019-07-02 14:19 ` [PATCH v6 17/18] drm/virtio: drop virtio_gpu_object_{reserve,unreserve} Gerd Hoffmann
2019-07-02 14:19 ` [PATCH v6 18/18] drm/virtio: add fence sanity check Gerd Hoffmann
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