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Currently, we are using an alignment of 128 kB to insert a node, which ends up wasting memory as we perform plenty of small BOs allocations (<= 4 kB). We require that allocations are aligned to 128Kb so for any allocation smaller than that, we are wasting the difference. This implies that we cannot effectively use the whole 4 GB address space available for the GPU in the RPi 4. Currently, we can allocate up to 32000 BOs of 4 kB (~140 MB) and 3000 BOs of 400 kB (~1,3 GB). This can be quite limiting for applications that have a high memory requirement, such as vkoverhead [1]. By reducing the page alignment to 4 kB, we can allocate up to 1000000 BOs of 4 kB (~4 GB) and 10000 BOs of 400 kB (~4 GB). Moreover, by performing benchmarks, we were able to attest that reducing the page alignment to 4 kB can provide a general performance improvement in OpenGL applications (e.g. glmark2). Therefore, this patch reduces the alignment of the node allocation to 4 kB, which will allow RPi users to explore the whole 4GB virtual address space provided by the hardware. Also, this patch allow users to fully run vkoverhead in the RPi 4/5, solving the issue reported in [1]. [1] https://github.com/zmike/vkoverhead/issues/14 Signed-off-by: Maíra Canal <mcanal@igalia.com> Reviewed-by: Iago Toral Quiroga <itoral@igalia.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240923141348.2422499-8-mcanal@igalia.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.