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Jason Gunthorpe says: ==================== iommufd follows the same design as KVM and uses memory cgroups to limit the amount of kernel memory a iommufd file descriptor can pin down. The various internal data structures already use GFP_KERNEL_ACCOUNT to charge its own memory. However, one of the biggest consumers of kernel memory is the IOPTEs stored under the iommu_domain and these allocations are not tracked. This series is the first step in fixing it. The iommu driver contract already includes a 'gfp' argument to the map_pages op, allowing iommufd to specify GFP_KERNEL_ACCOUNT and then having the driver allocate the IOPTE tables with that flag will capture a significant amount of the allocations. Update the iommu_map() API to pass in the GFP argument, and fix all call sites. Replace iommu_map_atomic(). Audit the "enterprise" iommu drivers to make sure they do the right thing. Intel and S390 ignore the GFP argument and always use GFP_ATOMIC. This is problematic for iommufd anyhow, so fix it. AMD and ARM SMMUv2/3 are already correct. A follow up series will be needed to capture the allocations made when the iommu_domain itself is allocated, which will complete the job. ==================== * 'iommu-memory-accounting' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/joro/iommu: iommu/s390: Use GFP_KERNEL in sleepable contexts iommu/s390: Push the gfp parameter to the kmem_cache_alloc()'s iommu/intel: Use GFP_KERNEL in sleepable contexts iommu/intel: Support the gfp argument to the map_pages op iommu/intel: Add a gfp parameter to alloc_pgtable_page() iommufd: Use GFP_KERNEL_ACCOUNT for iommu_map() iommu/dma: Use the gfp parameter in __iommu_dma_alloc_noncontiguous() iommu: Add a gfp parameter to iommu_map_sg() iommu: Remove iommu_map_atomic() iommu: Add a gfp parameter to iommu_map() Link: https://lore.kernel.org/linux-iommu/0-v3-76b587fe28df+6e3-iommu_map_gfp_jgg@nvidia.com Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
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.