Commit 212c5c07 authored by Pasha Tatashin's avatar Pasha Tatashin Committed by Joerg Roedel
Browse files

iommu: account IOMMU allocated memory 



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.

There is a difference between GFP_ACCOUNT and what NR_IOMMU_PAGES shows.
GFP_ACCOUNT is set only where it makes sense to charge to user
processes, i.e. IOMMU Page Tables, but there more IOMMU shared data
that should not really be charged to a specific process.

Signed-off-by: default avatarPasha Tatashin <pasha.tatashin@soleen.com>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Tested-by: default avatarBagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20240413002522.1101315-12-pasha.tatashin@soleen.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent bd3520a9

Documentation/admin-guide/cgroup-v2.rst

+1 −1
Original line number Diff line number Diff line
@@ -1432,7 +1432,7 @@ 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

Documentation/filesystems/proc.rst

+2 −2
Original line number Diff line number Diff line
@@ -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.

drivers/iommu/iommu-pages.h

+2 −0
Original line number Diff line number Diff line
@@ -30,6 +30,7 @@ static inline void __iommu_alloc_account(struct page *page, int order) 
	const long pgcnt = 1l << order;



	mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, pgcnt);

	mod_lruvec_page_state(page, NR_SECONDARY_PAGETABLE, pgcnt);

}



/**
@@ -42,6 +43,7 @@ static inline void __iommu_free_account(struct page *page, int order) 
	const long pgcnt = 1l << order;



	mod_node_page_state(page_pgdat(page), NR_IOMMU_PAGES, -pgcnt);

	mod_lruvec_page_state(page, NR_SECONDARY_PAGETABLE, -pgcnt);

}



/**

include/linux/mmzone.h

+1 −1
Original line number Diff line number Diff line
@@ -205,7 +205,7 @@ 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