linux-kernel - Re: [PATCH v6 0/4] drm: Use full allocated minor range for DRM

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Date: Thu, 2 May 2024 18:22:26 -0700
From: Eric Pilmore <epilmore@...aio.com>
To: Michał Winiarski <michal.winiarski@...el.com>
Cc: dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org,
 intel-gfx@...ts.freedesktop.org,
 David Airlie <airlied@...ux.ie>,
 Daniel Vetter <daniel@...ll.ch>,
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>,
 Thomas Zimmermann <tzimmermann@...e.de>,
 Simon Ser <contact@...rsion.fr>,
 Matthew Wilcox <willy@...radead.org>,
 Oded Gabbay <ogabbay@...nel.org>,
 Christian König <christian.koenig@....com>,
 James Zhu <James.Zhu@....com>,
 Pekka Paalanen <pekka.paalanen@...labora.com>,
 Emil Velikov <emil.l.velikov@...il.com>
Subject: Re: [PATCH v6 0/4] drm: Use full allocated minor range for DRM



> On Jul 24, 2023, at 2:14 PM, Michał Winiarski <michal.winiarski@...el.com> wrote:
> 
> 64 DRM device nodes is not enough for everyone.
> Upgrade it to ~512K (which definitely is more than enough).
> 
> To allow testing userspace support for >64 devices, add additional DRM
> modparam (force_extended_minors) which causes DRM to skip allocating minors
> in 0-192 range.
> Additionally - convert minors to use XArray instead of IDR to simplify the
> locking.
> 
> v1 -> v2:
> Don't touch DRM_MINOR_CONTROL and its range (Simon Ser)
> 
> v2 -> v3:
> Don't use legacy scheme for >=192 minor range (Dave Airlie)
> Add modparam for testing (Dave Airlie)
> Add lockdep annotation for IDR (Daniel Vetter)
> 
> v3 -> v4:
> Convert from IDR to XArray (Matthew Wilcox)
> 
> v4 -> v5:
> Fixup IDR to XArray conversion (Matthew Wilcox)
> 
> v5 -> v6:
> Also convert Accel to XArray
> Rename skip_legacy_minors to force_extended_minors
> 
> Michał Winiarski (4):
>  drm: Use XArray instead of IDR for minors
>  accel: Use XArray instead of IDR for minors
>  drm: Expand max DRM device number to full MINORBITS
>  drm: Introduce force_extended_minors modparam
> 
> drivers/accel/drm_accel.c      | 110 +++------------------------------
> drivers/gpu/drm/drm_drv.c      | 105 ++++++++++++++++---------------
> drivers/gpu/drm/drm_file.c     |   2 +-
> drivers/gpu/drm/drm_internal.h |   4 --
> include/drm/drm_accel.h        |  18 +-----
> include/drm/drm_file.h         |   5 ++
> 6 files changed, 69 insertions(+), 175 deletions(-)
> 
> -- 
> 2.41.0
> 


Hi Michal,

What is the status on this patch? Did it ever get accepted upstream?
If so, what release? I don’t see the changes in the latest Linux kernel.
I am working on a system that involves a large number of GPUs, where
each GPU consumes a number of DRM devices. As such, I’m easily
exceeding the current limit of 64 in the (6.6) kernel. To workaround this issue,
I have temporarily picked up this patch which is doing the trick, but now
I’m wondering if this patch has seen the light of day in the Linux kernel.

Thanks for any info!

Regards,
Eric