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Subject: Re: [PATCH 0/3] drm: omapdrm: Fix excessive GEM buffers DMM/CMA usage
To:     tomba@kernel.org, airlied@linux.ie, daniel@ffwll.ch
Cc:     dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        linux-omap@vger.kernel.org, merlijn@wizzup.org, tony@atomide.com
References: <1642587791-13222-1-git-send-email-ivo.g.dimitrov.75@gmail.com>
From:   Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Message-ID: <f517358f-fb6c-3343-5d3a-006bd459f6ba@gmail.com>
Date:   Mon, 14 Feb 2022 09:08:35 +0200
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gentle ping

On 19.01.22 г. 12:23 ч., Ivaylo Dimitrov wrote:
> This patch series fixes excessive DMM or CMA usage of GEM buffers leading to
> various runtime allocation failures. The series enables daily usage of devices
> without exausting limited resources like CMA or DMM space if GPU rendering is
> needed.
> 
> The first patch doesn't bring any functional changes, it just moves some
> TILER/DMM related code to a separate function, to simplify the review of the
> next two patches.
> 
> The second patch allows off-CPU rendering to non-scanout buffers. Without that
> patch, it is basically impossible to use the driver allocated GEM buffers on
> OMAP3 for anything else but a basic CPU rendered examples as if we want GPU
> rendering, we must allocate buffers as scanout buffers, which are CMA allocated.
> CMA soon gets fragmented and we start seeing allocation failures. Such failres
> in Xorg cannot be handeled gracefully, so the system is basically unusable.
> 
> Third patch fixes similar issue on OMAP4/5, where DMM/TILER spaces get
> fragmented with time, leading to allocation failures.
> 
> Series were tested on Motolola Droid4 and Nokia N900, with OMAP DDX and
> PVR EXA from https://github.com/maemo-leste/xf86-video-omap
> 
> Ivaylo Dimitrov (3):
>    drm: omapdrm: simplify omap_gem_pin
>    drm: omapdrm: Support exporting of non-contiguous GEM BOs
>    drm: omapdrm: Do no allocate non-scanout GEMs through DMM/TILER
> 
>   drivers/gpu/drm/omapdrm/omap_gem.c        | 198 +++++++++++++++++-------------
>   drivers/gpu/drm/omapdrm/omap_gem.h        |   3 +-
>   drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c |   5 +-
>   3 files changed, 116 insertions(+), 90 deletions(-)
>