2236439bc6
Frequent mapping and unmapping a buffer object adds overhead for modifying the page table and creates debug output. Unmapping a buffer is only required when the memory manager evicts the buffer from its current location. v4: * WARN_ON if buffer is still mapped during BO cleanup Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Reported-and-tested-by: Davidlohr Bueso <dbueso@suse.de> Link: https://patchwork.freedesktop.org/patch/msgid/20190906122056.32018-5-tzimmermann@suse.de
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.