[PATCH 14/16] iommu: account IOMMU allocated memory

Pasha Tatashin
2023-11-28T20:50:29Z

In order to be able to limit the amount of memory that is allocated
by IOMMU subsystem, the memory must be accounted.

Account IOMMU as part of the secondary pagetables as it was discussed
at LPC.

The value of SecPageTables now contains mmeory allocation by IOMMU
and KVM.

Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com>
---
Documentation/admin-guide/cgroup-v2.rst | 2 +-
Documentation/filesystems/proc.rst | 4 ++--
drivers/iommu/iommu-pages.h | 2 ++
include/linux/mmzone.h | 2 +-
4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 3f85254f3cef..e004e05a7cde 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1418,7 +1418,7 @@ PAGE_SIZE multiple when read back.
sec_pagetables
Amount of memory allocated for secondary page tables,
this currently includes KVM mmu allocations on x86
- and arm64.
+ and arm64 and IOMMU page tables.

percpu (npn)
Amount of memory used for storing per-cpu kernel
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 49ef12df631b..86f137a9b66b 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -1110,8 +1110,8 @@ KernelStack
PageTables
Memory consumed by userspace page tables
SecPageTables
- Memory consumed by secondary page tables, this currently
- currently includes KVM mmu allocations on x86 and arm64.
+ Memory consumed by secondary page tables, this currently includes
+ KVM mmu and IOMMU allocations on x86 and arm64.
NFS_Unstable
Always zero. Previous counted pages which had been written to
the server, but has not been committed to stable storage.
diff --git a/drivers/iommu/iommu-pages.h b/drivers/iommu/iommu-pages.h
index 69895a355c0c..cdd257585284 100644
--- a/drivers/iommu/iommu-pages.h
+++ b/drivers/iommu/iommu-pages.h
@@ -27,6 +27,7 @@ static inline void __iommu_alloc_account(struct page *pages, int order)
const long pgcnt = 1l << order;

mod_node_page_state(page_pgdat(pages), NR_IOMMU_PAGES, pgcnt);
+ mod_lruvec_page_state(pages, NR_SECONDARY_PAGETABLE, pgcnt);
}

/**
@@ -39,6 +40,7 @@ static inline void __iommu_free_account(struct page *pages, int order)
const long pgcnt = 1l << order;

mod_node_page_state(page_pgdat(pages), NR_IOMMU_PAGES, -pgcnt);
+ mod_lruvec_page_state(pages, NR_SECONDARY_PAGETABLE, -pgcnt);
}

/**
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 1a4d0bba3e8b..aaabb385663c 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -199,7 +199,7 @@ enum node_stat_item {
NR_KERNEL_SCS_KB, /* measured in KiB */
#endif
NR_PAGETABLE, /* used for pagetables */
- NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */
+ NR_SECONDARY_PAGETABLE, /* secondary pagetables, KVM & IOMMU */
#ifdef CONFIG_IOMMU_SUPPORT
NR_IOMMU_PAGES, /* # of pages allocated by IOMMU */
#endif
--
2.43.0.rc2.451.g8631bc7472-goog