27a5dcfe73
I915_GEM_THROTTLE dates back to the time before contexts where there was just a single engine, and therefore a single timeline and request list globally. That request list was in execution/retirement order, and so walking it to find a particular aged request made sense and could be split per file. That is no more. We now have many timelines with a file, as many as the user wants to construct (essentially per-engine, per-context). Each of those run independently and so make the single list futile. Remove the disordered list, and iterate over all the timelines to find a request to wait on in each to satisfy the criteria that the CPU is no more than 20ms ahead of its oldest request. It should go without saying that the I915_GEM_THROTTLE ioctl is no longer used as the primary means of throttling, so it makes sense to push the complication into the ioctl where it only impacts upon its few irregular users, rather than the execbuf/retire where everybody has to pay the cost. Fortunately, the few users do not create vast amount of contexts, so the loops over contexts/engines should be concise. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200728152010.30701-1-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.