2023-01-18 18:02:33

by Jason Gunthorpe

Subject: [PATCH v2 05/10] iommufd: Use GFP_KERNEL_ACCOUNT for iommu_map()

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.

However, one of the biggest consumers of kernel memory is the IOPTEs
stored under the iommu_domain. Many drivers will allocate these at
iommu_map() time and will trivially do the right thing if we pass in
GFP_KERNEL_ACCOUNT.

Signed-off-by: Jason Gunthorpe <[email protected]>
---
drivers/iommu/iommufd/pages.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/iommufd/pages.c b/drivers/iommu/iommufd/pages.c
index 22cc3bb0c6c55a..f8d92c9bb65b60 100644
--- a/drivers/iommu/iommufd/pages.c
+++ b/drivers/iommu/iommufd/pages.c
@@ -457,7 +457,7 @@ static int batch_iommu_map_small(struct iommu_domain *domain,

while (size) {
rc = iommu_map(domain, iova, paddr, PAGE_SIZE, prot,
- GFP_KERNEL);
+ GFP_KERNEL_ACCOUNT);
if (rc)
goto err_unmap;
iova += PAGE_SIZE;
@@ -502,7 +502,7 @@ static int batch_to_domain(struct pfn_batch *batch, struct iommu_domain *domain,
rc = iommu_map(domain, iova,
PFN_PHYS(batch->pfns[cur]) + page_offset,
next_iova - iova, area->iommu_prot,
- GFP_KERNEL);
+ GFP_KERNEL_ACCOUNT);
if (rc)
goto err_unmap;
iova = next_iova;
--
2.39.0

2023-01-20 04:34:04

by Tian, Kevin

Subject: RE: [PATCH v2 05/10] iommufd: Use GFP_KERNEL_ACCOUNT for iommu_map()

> From: Jason Gunthorpe <[email protected]>
> Sent: Thursday, January 19, 2023 2:01 AM
>
> 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.
>
> However, one of the biggest consumers of kernel memory is the IOPTEs
> stored under the iommu_domain. Many drivers will allocate these at
> iommu_map() time and will trivially do the right thing if we pass in
> GFP_KERNEL_ACCOUNT.
>
> Signed-off-by: Jason Gunthorpe <[email protected]>

Reviewed-by: Kevin Tian <[email protected]>