c18636f763
Since the breadcrumb enabling/cancelling itself is serialised by the breadcrumbs.irq_lock, with a bit of care we can remove the outer serialisation with i915_request.lock for concurrent dma_fence_enable_signaling(). This has the important side-effect of eliminating the nested i915_request.lock within request submission. The challenge in serialisation is around the unsubmission where we take an active request that wants a breadcrumb on the signaling engine and put it to sleep. We do not want a concurrent dma_fence_enable_signaling() to attach a breadcrumb as we unsubmit, so we must mark the request as no longer active before serialising with the concurrent enable-signaling. On retire, we serialise with the concurrent enable-signaling, but instead of clearing ACTIVE, we mark it as SIGNALED. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200731154834.8378-1-chris@chris-wilson.co.uk Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> [Joonas: Rebased and reordered into drm-intel-gt-next branch] 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.