c4b17afb0a
Change function __iommu_dma_alloc_pages() to allocate pages for DMA from respective device NUMA node. The ternary operator which would be for alloc_pages_node() is tidied along with this. The motivation for this change is to have a policy for page allocation consistent with direct DMA mapping, which attempts to allocate pages local to the device, as mentioned in [1]. In addition, for certain workloads it has been observed a marginal performance improvement. The patch caused an observation of 0.9% average throughput improvement for running tcrypt with HiSilicon crypto engine. We also include a modification to use kvzalloc() for kzalloc()/vzalloc() combination. [1] https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1692998.html Signed-off-by: Ganapatrao Kulkarni <ganapatrao.kulkarni@cavium.com> [JPG: Added kvzalloc(), drop pages ** being device local, remove ternary operator, update message] Signed-off-by: John Garry <john.garry@huawei.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Signed-off-by: Joerg Roedel <jroedel@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.