060bb115c2
On 32b, highmem using a finite set of indirect PTE (i.e. vmap) to provide virtual mappings of the high pages. As these are finite, map_new_virtual() must wait for some other kmap() to finish when it runs out. If we map a large number of objects, there is no method for it to tell us to release the mappings, and we deadlock. However, if we make an explicit vmap of the page, that uses a larger vmalloc arena, and also has the ability to tell us to release unwanted mappings. Most importantly, it will fail and propagate an error instead of waiting forever. Fixes:fb8621d3be("drm/i915: Avoid allocating a vmap arena for a single page") #x86-32 References:e87666b52f("drm/i915/shrinker: Hook up vmap allocation failure notifier") Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Matthew Auld <matthew.auld@intel.com> Cc: <stable@vger.kernel.org> # v4.7+ Link: https://patchwork.freedesktop.org/patch/msgid/20200915091417.4086-1-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.