[PATCH v3 2/2] drm/uapi: add explicit virtgpu context debug name

[Gurchetan Singh]

On Tue, Oct 31, 2023 at 8:55 AM Gurchetan Singh <gurchetansingh at chromium.org>
wrote:

>
>
> On Sun, Oct 22, 2023 at 4:50 PM Dmitry Osipenko <
> dmitry.osipenko at collabora.com> wrote:
>
>> On 10/18/23 21:17, Gurchetan Singh wrote:
>> > There are two problems with the current method of determining the
>> > virtio-gpu debug name.
>> >
>> > 1) TASK_COMM_LEN is defined to be 16 bytes only, and this is a
>> >    Linux kernel idiom (see PR_SET_NAME + PR_GET_NAME). Though,
>> >    Android/FreeBSD get around this via setprogname(..)/getprogname(..)
>> >    in libc.
>> >
>> >    On Android, names longer than 16 bytes are common.  For example,
>> >    one often encounters a program like "com.android.systemui".
>> >
>> >    The virtio-gpu spec allows the debug name to be up to 64 bytes, so
>> >    ideally userspace should be able to set debug names up to 64 bytes.
>> >
>> > 2) The current implementation determines the debug name using whatever
>> >    task initiated virtgpu.  This is could be a "RenderThread" of a
>> >    larger program, when we actually want to propagate the debug name
>> >    of the program.
>> >
>> > To fix these issues, add a new CONTEXT_INIT param that allows userspace
>> > to set the debug name when creating a context.
>> >
>> > It takes a null-terminated C-string as the param value. The length of
>> the
>> > string (excluding the terminator) **should** be <= 64 bytes.  Otherwise,
>> > the debug_name will be truncated to 64 bytes.
>> >
>> > Link to open-source userspace:
>> >
>> https://android-review.googlesource.com/c/platform/hardware/google/gfxstream/+/2787176
>> >
>> > Signed-off-by: Gurchetan Singh <gurchetansingh at chromium.org>
>> > Reviewed-by: Josh Simonot <josh.simonot at gmail.com>
>> > ---
>> > Fixes suggested by Dmitry Osipenko
>> > v2:
>> >     - Squash implementation and UAPI change into one commit
>> >     - Avoid unnecessary casts
>> >     - Use bool when necessary
>> > v3:
>> >     - Use DEBUG_NAME_MAX_LEN - 1 when copying string
>> >
>> >  drivers/gpu/drm/virtio/virtgpu_drv.h   |  5 ++++
>> >  drivers/gpu/drm/virtio/virtgpu_ioctl.c | 39 ++++++++++++++++++++++----
>> >  include/uapi/drm/virtgpu_drm.h         |  2 ++
>> >  3 files changed, 40 insertions(+), 6 deletions(-)
>>
>> Gerd, do you have objections to this UAPI change?
>>
>
> Bump.  I say we wait another week and see if anyone cares [I suspect
> nobody does].
>
>
> https://drm.pages.freedesktop.org/maintainer-tools/committer-drm-misc.html#merge-criteria
>
> As per DRM guidelines, if there are no open comments and the change is
> reviewed, it is mergeable.
>

*hears crickets*

Can we merge this now?


>
>>
>> --
>> Best regards,
>> Dmitry
>>
>>
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