cad7109a2b
As we start to introduce asynchronous failsafe object migration, where we update the object state and then submit asynchronous commands we need to record what memory resources are actually used by various part of the command stream. Initially for three purposes: 1) Error capture. 2) Asynchronous migration error recovery. 3) Asynchronous vma bind. At the time where these happens, the object state may have been updated to be several migrations ahead and object sg-tables discarded. In order to make it possible to keep sg-tables with memory resource information for these operations, introduce refcounted sg-tables that aren't freed until the last user is done with them. The alternative would be to reference information sitting on the corresponding ttm_resources which typically have the same lifetime as these refcountes sg_tables, but that leads to other awkward constructs: Due to the design direction chosen for ttm resource managers that would lead to diamond-style inheritance, the LMEM resources may sometimes be prematurely freed, and finally the subclassed struct ttm_resource would have to bleed into the asynchronous vma bind code. v3: - Address a number of style issues (Matthew Auld) v4: - Dont check for st->sgl being NULL in i915_ttm_tt__shmem_unpopulate(), that should never happen. (Matthew Auld) v5: - Fix a Potential double-free (Matthew Auld) Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20211101122444.114607-1-thomas.hellstrom@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.