Merge branch 'iommu-memory-accounting' of ssh://gitolite.kernel.org/pub/scm/linux/kernel/git/joro/iommu intoiommufd/for-next

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>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index 1e1d3509efae..f8d92c9bb65b 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -456,7 +456,8 @@ static int batch_iommu_map_small(struct iommu_domain *domain,
 			size % PAGE_SIZE);
 
 	while (size) {
-		rc = iommu_map(domain, iova, paddr, PAGE_SIZE, prot);
+		rc = iommu_map(domain, iova, paddr, PAGE_SIZE, prot,
+			       GFP_KERNEL_ACCOUNT);
 		if (rc)
 			goto err_unmap;
 		iova += PAGE_SIZE;
@@ -500,7 +501,8 @@ static int batch_to_domain(struct pfn_batch *batch, struct iommu_domain *domain,
 		else
 			rc = iommu_map(domain, iova,
 				       PFN_PHYS(batch->pfns[cur]) + page_offset,
-				       next_iova - iova, area->iommu_prot);
+				       next_iova - iova, area->iommu_prot,
+				       GFP_KERNEL_ACCOUNT);
 		if (rc)
 			goto err_unmap;
 		iova = next_iova;