[13/16] iommu: observability of the IOMMU allocations
Commit Message
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: Pasha Tatashin <pasha.tatashin@soleen.com>
---
drivers/iommu/iommu-pages.h | 30 ++++++++++++++++++++++++++++++
include/linux/mmzone.h | 3 +++
mm/vmstat.c | 3 +++
3 files changed, 36 insertions(+)
Comments
Hi Pasha,
kernel test robot noticed the following build errors:
[auto build test ERROR on akpm-mm/mm-everything]
[also build test ERROR on awilliam-vfio/for-linus linus/master v6.7-rc3]
[cannot apply to joro-iommu/next awilliam-vfio/next next-20231130]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Pasha-Tatashin/iommu-vt-d-add-wrapper-functions-for-page-allocations/20231129-054908
base: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link: https://lore.kernel.org/r/20231128204938.1453583-14-pasha.tatashin%40soleen.com
patch subject: [PATCH 13/16] iommu: observability of the IOMMU allocations
config: sparc64-randconfig-r054-20231130 (https://download.01.org/0day-ci/archive/20231130/202311302108.WERv9oSO-lkp@intel.com/config)
compiler: sparc64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231130/202311302108.WERv9oSO-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202311302108.WERv9oSO-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from drivers/iommu/iommufd/iova_bitmap.c:11:
drivers/iommu/iommufd/../iommu-pages.h: In function '__iommu_alloc_account':
>> drivers/iommu/iommufd/../iommu-pages.h:29:48: error: 'NR_IOMMU_PAGES' undeclared (first use in this function)
29 | mod_node_page_state(page_pgdat(pages), NR_IOMMU_PAGES, pgcnt);
| ^~~~~~~~~~~~~~
drivers/iommu/iommufd/../iommu-pages.h:29:48: note: each undeclared identifier is reported only once for each function it appears in
drivers/iommu/iommufd/../iommu-pages.h: In function '__iommu_free_account':
drivers/iommu/iommufd/../iommu-pages.h:41:48: error: 'NR_IOMMU_PAGES' undeclared (first use in this function)
41 | mod_node_page_state(page_pgdat(pages), NR_IOMMU_PAGES, -pgcnt);
| ^~~~~~~~~~~~~~
vim +/NR_IOMMU_PAGES +29 drivers/iommu/iommufd/../iommu-pages.h
13
14 /*
15 * All page allocation that are performed in the IOMMU subsystem must use one of
16 * the functions below. This is necessary for the proper accounting as IOMMU
17 * state can be rather large, i.e. multiple gigabytes in size.
18 */
19
20 /**
21 * __iommu_alloc_account - account for newly allocated page.
22 * @pages: head struct page of the page.
23 * @order: order of the page
24 */
25 static inline void __iommu_alloc_account(struct page *pages, int order)
26 {
27 const long pgcnt = 1l << order;
28
> 29 mod_node_page_state(page_pgdat(pages), NR_IOMMU_PAGES, pgcnt);
30 }
31
@@ -17,6 +17,30 @@
* state can be rather large, i.e. multiple gigabytes in size.
*/
+/**
+ * __iommu_alloc_account - account for newly allocated page.
+ * @pages: head struct page of the page.
+ * @order: order of the page
+ */
+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);
+}
+
+/**
+ * __iommu_free_account - account a page that is about to be freed.
+ * @pages: head struct page of the page.
+ * @order: order of the page
+ */
+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);
+}
+
/**
* __iommu_alloc_pages_node - allocate a zeroed page of a given order from
* specific NUMA node.
@@ -35,6 +59,8 @@ static inline struct page *__iommu_alloc_pages_node(int nid, gfp_t gfp,
if (!pages)
return NULL;
+ __iommu_alloc_account(pages, order);
+
return pages;
}
@@ -53,6 +79,8 @@ static inline struct page *__iommu_alloc_pages(gfp_t gfp, int order)
if (!pages)
return NULL;
+ __iommu_alloc_account(pages, order);
+
return pages;
}
@@ -89,6 +117,7 @@ static inline void __iommu_free_pages(struct page *pages, int order)
if (!pages)
return;
+ __iommu_free_account(pages, order);
__free_pages(pages, order);
}
@@ -192,6 +221,7 @@ static inline void iommu_free_pages_list(struct list_head *pages)
struct page *p = list_entry(pages->prev, struct page, lru);
list_del(&p->lru);
+ __iommu_free_account(p, 0);
put_page(p);
}
}
@@ -200,6 +200,9 @@ 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
@@ -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