[PATCH v3 00/10] Let iommufd charge IOPTE allocations to the memory cgroup

Jason Gunthorpe
2023-01-23T20:36:26Z

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.

v3:
- Leave a GFP_ATOMIC in "Add a gfp parameter to iommu_map_sg()"
and move the conversion to gfp argument to "Use the gfp parameter in
__iommu_dma_alloc_noncontiguous()"
- Mask off the zone/policy flags from gfp before doing internal
allocations and add a comment about Robin's note that this is to keep
the buffer and internal seperate.
v2: https://lore.kernel.org/r/0-v2-ce66f632bd0d+484-iommu_map_gfp_jgg@nvidia.com
- Prohibit bad GFP flags in the iommu wrappers
- Split out the new GFP_KERNEL usages into dedicated patches so it is
easier to check. No code change after the full series
v1: https://lore.kernel.org/r/0-v1-6e8b3997c46d+89e-iommu_map_gfp_jgg@nvidia.com

Jason Gunthorpe (10):
iommu: Add a gfp parameter to iommu_map()
iommu: Remove iommu_map_atomic()
iommu: Add a gfp parameter to iommu_map_sg()
iommu/dma: Use the gfp parameter in __iommu_dma_alloc_noncontiguous()
iommufd: Use GFP_KERNEL_ACCOUNT for iommu_map()
iommu/intel: Add a gfp parameter to alloc_pgtable_page()
iommu/intel: Support the gfp argument to the map_pages op
iommu/intel: Use GFP_KERNEL in sleepable contexts
iommu/s390: Push the gfp parameter to the kmem_cache_alloc()'s
iommu/s390: Use GFP_KERNEL in sleepable contexts

arch/arm/mm/dma-mapping.c | 11 ++--
arch/s390/include/asm/pci_dma.h | 5 +-
arch/s390/pci/pci_dma.c | 31 ++++++-----
.../drm/nouveau/nvkm/subdev/instmem/gk20a.c | 3 +-
drivers/gpu/drm/tegra/drm.c | 2 +-
drivers/gpu/host1x/cdma.c | 2 +-
drivers/infiniband/hw/usnic/usnic_uiom.c | 4 +-
drivers/iommu/dma-iommu.c | 18 +++++--
drivers/iommu/intel/iommu.c | 36 +++++++------
drivers/iommu/intel/iommu.h | 2 +-
drivers/iommu/intel/pasid.c | 2 +-
drivers/iommu/iommu.c | 53 +++++++------------
drivers/iommu/iommufd/pages.c | 6 ++-
drivers/iommu/s390-iommu.c | 15 +++---
drivers/media/platform/qcom/venus/firmware.c | 2 +-
drivers/net/ipa/ipa_mem.c | 6 ++-
drivers/net/wireless/ath/ath10k/snoc.c | 2 +-
drivers/net/wireless/ath/ath11k/ahb.c | 4 +-
drivers/remoteproc/remoteproc_core.c | 5 +-
drivers/vfio/vfio_iommu_type1.c | 9 ++--
drivers/vhost/vdpa.c | 2 +-
include/linux/iommu.h | 31 +++--------
22 files changed, 126 insertions(+), 125 deletions(-)

base-commit: 5dc4c995db9eb45f6373a956eb1f69460e69e6d4
--
2.39.0