89351925a4
The GEM object is grossly overweight for the practicality of tracking large numbers of individual pages, yet it is currently our only abstraction for tracking DMA allocations. Since those allocations need to be reserved upfront before an operation, and that we need to break away from simple system memory, we need to ditch using plain struct page wrappers. In the process, we drop the WC mapping as we ended up clflushing everything anyway due to various issues across a wider range of platforms. Though in a future step, we need to drop the kmap_atomic approach which suggests we need to pre-map all the pages and keep them mapped. v2: Verify our large scratch page is suitably DMA aligned; and manually clear the scratch since we are allocating plain struct pages full of prior content. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Matthew Auld <matthew.auld@intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200729164219.5737-2-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.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 Restructured Text 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.