gpu: ion: Request highmem pages for IOMMU heap

When allocating pages for IOMMU heap it is advantageous
to try to allocate pages from highmem in addition to
lowmem since clients using the IOMMU heap can use
either highmem or lowmem.
gpu: ion: Use writecombine for uncached mappings

When we map ion buffers as uncached we want to map them as
uncached but still be able to use buffering of transactions
since turning off buffering has a severe performance impact.
gpu: ion: replace __GFP_ZERO with manual zero'ing

As a performance optimization, omit the __GFP_ZERO flag when
allocating individual pages and, instead, zero out all of the pages in
one fell swoop.
gpu: ion: allocate huge pages in iommu heap

As a performance optimization, use higher-order page allocations if
possible. This can reduce TLB misses and the total number of page
structures.
gpu: ion: suppress excessive logging for expected failure cases

We expect alloc_pages to fail for high-order pages under stressed
memory conditions. It should then fall back to lower-order page
allocations but due to excessive logging the system crashes. Use
__GFP_NOWARN for high-order allocations to avoid excessive logging.
gpu: ion: Align va address to biggest buffer size

Align the virtual address to the max buffer size to
allow IOMMU mappings at the biggest buffer size
gpu: ion: Minimize allocation fallback delay

When we allocate from iommu heap we first try to allocate 1M pages. If
that fails we try 64K pages, which falls back to 4K pages. However,
we don't want to incur too much overhead when allocating with fallbacks
so we don't want the higher order page allocation to retry, perform
reclaim, or run memory compaction.

Configure the GFP flags to ensure that when we allocate pages greater
than order 0 we don't try to do any retries, reclaim, access emergency
pools, or run memory compaction. This will ensure lower memory allocation
latency for applications.
gpu: ion: enable the kmalloc heap

There are some Ion clients who would like to use the kmalloc
heap. Enable it.

+ ion: isolate msm-specific ion extensions - part 3
msm: Add support for ION Flushing without virtual address

Video has very large buffers to be flushed. Due to lack of
vmalloc space, ion_map_kernel cannot be called on each of
the video buffers. With this change the ion handle can be
flushed without the need of the kernel mapping.
gpu: ion: Use correct type for variables

Use correct type for variables to prevent overflow of signed
type when assiging from an unsigned type.
gpu: ion: Do fallback when allocating large sizes

The preferred allocation of memory for kernel data structures in
ION is to use kmalloc. This is mainly for performance reasons. However,
we are not guaranteed to be able to allocate large sizes. So to keep
the code performing well and at the same time allow for larger allocations,
implement a fallback mechanism for allocation of memory for ION kernel data
structures.