netdev - [PATCH 5/8] iommufd: Use GFP_KERNEL_ACCOUNT for iommu

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Message-Id: <5-v1-6e8b3997c46d+89e-iommu_map_gfp_jgg@nvidia.com>
Date:   Fri,  6 Jan 2023 12:42:45 -0400
From:   Jason Gunthorpe <jgg@...dia.com>
To:     Lu Baolu <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        Kevin Tian <kevin.tian@...el.com>,
        Matthew Rosato <mjrosato@...ux.ibm.com>,
        Robin Murphy <robin.murphy@....com>
Cc:     Alex Williamson <alex.williamson@...hat.com>,
        ath10k@...ts.infradead.org, ath11k@...ts.infradead.org,
        Christian Borntraeger <borntraeger@...ux.ibm.com>,
        dri-devel@...ts.freedesktop.org, iommu@...ts.linux.dev,
        kvm@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-media@...r.kernel.org,
        linux-rdma@...r.kernel.org, linux-remoteproc@...r.kernel.org,
        linux-s390@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        linux-tegra@...r.kernel.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org, nouveau@...ts.freedesktop.org,
        Niklas Schnelle <schnelle@...ux.ibm.com>,
        virtualization@...ts.linux-foundation.org
Subject: [PATCH 5/8] 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 <jgg@...dia.com>
---
 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