Commit bd3520a9 authored by Pasha Tatashin's avatar Pasha Tatashin Committed by Joerg Roedel
Browse files

iommu: observability of the IOMMU allocations 



Add NR_IOMMU_PAGES into node_stat_item that counts number of pages
that are allocated by the IOMMU subsystem.

The allocations can be view per-node via:
/sys/devices/system/node/nodeN/vmstat.

For example:

$ grep iommu /sys/devices/system/node/node*/vmstat
/sys/devices/system/node/node0/vmstat:nr_iommu_pages 106025
/sys/devices/system/node/node1/vmstat:nr_iommu_pages 3464

The value is in page-count, therefore, in the above example
the iommu allocations amount to ~428M.

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/20240413002522.1101315-11-pasha.tatashin@soleen.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 8e8b4ac5

drivers/iommu/iommu-pages.h

+30 −0
Original line number Diff line number Diff line
@@ -20,6 +20,30 @@ 
 * large, i.e. multiple gigabytes in size.

 */



/**

 * __iommu_alloc_account - account for newly allocated page.

 * @page: head struct page of the page.

 * @order: order of the page

 */

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);

}



/**

 * __iommu_free_account - account a page that is about to be freed.

 * @page: head struct page of the page.

 * @order: order of the page

 */

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);

}



/**

 * __iommu_alloc_pages - allocate a zeroed page of a given order.

 * @gfp: buddy allocator flags
@@ -35,6 +59,8 @@ static inline struct page *__iommu_alloc_pages(gfp_t gfp, int order) 
	if (unlikely(!page))

		return NULL;



	__iommu_alloc_account(page, order);



	return page;

}
@@ -48,6 +74,7 @@ static inline void __iommu_free_pages(struct page *page, int order) 
	if (!page)

		return;



	__iommu_free_account(page, order);

	__free_pages(page, order);

}
@@ -67,6 +94,8 @@ static inline void *iommu_alloc_pages_node(int nid, gfp_t gfp, int order) 
	if (unlikely(!page))

		return NULL;



	__iommu_alloc_account(page, order);



	return page_address(page);

}
@@ -147,6 +176,7 @@ static inline void iommu_put_pages_list(struct list_head *page) 
		struct page *p = list_entry(page->prev, struct page, lru);



		list_del(&p->lru);

		__iommu_free_account(p, 0);

		put_page(p);

	}

}

include/linux/mmzone.h

+3 −0
Original line number Diff line number Diff line
@@ -206,6 +206,9 @@ enum node_stat_item { 
#endif

	NR_PAGETABLE,		/* used for pagetables */

	NR_SECONDARY_PAGETABLE, /* secondary pagetables, e.g. KVM pagetables */

#ifdef CONFIG_IOMMU_SUPPORT

	NR_IOMMU_PAGES,		/* # of pages allocated by IOMMU */

#endif

#ifdef CONFIG_SWAP

	NR_SWAPCACHE,

#endif

mm/vmstat.c

+3 −0
Original line number Diff line number Diff line
@@ -1242,6 +1242,9 @@ const char * const vmstat_text[] = { 
#endif

	"nr_page_table_pages",

	"nr_sec_page_table_pages",

#ifdef CONFIG_IOMMU_SUPPORT

	"nr_iommu_pages",

#endif

#ifdef CONFIG_SWAP

	"nr_swapcached",

#endif