79c7a28e1f
Currently we use the engine->active.lock to ensure that the request is not retired as we capture the data. However, we only need to ensure that the vma are not removed prior to use acquiring their contents, and since we have already relinquished our stop-machine protection, we assume that the user will not be overwriting the contents before we are able to record them. In order to capture the vma outside of the spinlock, we acquire a reference and mark the vma as active to prevent it from being unbound. However, since it is tricky allocate an entry in the fence tree (doing so would require taking a mutex) while inside the engine spinlock, we use an atomic bit and special case the handling for i915_active_wait. The core benefit is that we can use some non-atomic methods for mapping the device pages, we can remove the slow compression phase out of atomic context (i.e. stop antagonising the nmi-watchdog), and no we longer need large reserves of atomic pages. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111215 Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190725223843.8971-1-chris@chris-wilson.co.uk
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.