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ptr_unpack_bits() is a function-like macro, as such it is meant to be replaceable by a function. In this case, we should be passing in the out-param as a pointer. Bizarrely this does affect code generation: function old new delta i915_gem_object_pin_map 409 389 -20 An improvement(?) in this case, but one can't help wonder what strict-aliasing optimisations we are preventing. The generated code looks identical in using ptr_unpack_bits (no extra motions to stack, the pointer and bits appear to be kept in registers), the difference appears to be code ordering and with a reorder it is able to use smaller forward jumps. Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-3-chris@chris-wilson.co.uk
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.