[PATCH v4 1/4] mm: add NR_SECONDARY_PAGETABLE to count secondary page table uses.

Yosry Ahmed
2022-04-29T20:11:52Z

Add NR_SECONDARY_PAGETABLE stat to count secondary page table uses, e.g.
KVM mmu. This provides more insights on the kernel memory used
by a workload.

This stat will be used by subsequent patches to count KVM mmu
memory usage.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
---
Documentation/admin-guide/cgroup-v2.rst | 5 +++++
Documentation/filesystems/proc.rst | 4 ++++
drivers/base/node.c | 2 ++
fs/proc/meminfo.c | 2 ++
include/linux/mmzone.h | 1 +
mm/memcontrol.c | 1 +
mm/page_alloc.c | 6 +++++-
mm/vmstat.c | 1 +
8 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 69d7a6983f78..828cb6b6f918 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1312,6 +1312,11 @@ PAGE_SIZE multiple when read back.
pagetables
Amount of memory allocated for page tables.

+ secondary_pagetables
+ Amount of memory allocated for secondary page tables,
+ this currently includes KVM mmu allocations on x86
+ and arm64.
+
percpu (npn)
Amount of memory used for storing per-cpu kernel
data structures.
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 061744c436d9..894d6317f3bd 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -973,6 +973,7 @@ You may not have all of these fields.
SReclaimable: 159856 kB
SUnreclaim: 124508 kB
PageTables: 24448 kB
+ SecPageTables: 0 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
@@ -1067,6 +1068,9 @@ SUnreclaim
PageTables
amount of memory dedicated to the lowest level of page
tables.
+SecPageTables
+ amount of memory dedicated to secondary page tables, this
+ currently includes KVM mmu 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/base/node.c b/drivers/base/node.c
index ec8bb24a5a22..9fe716832546 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -433,6 +433,7 @@ static ssize_t node_read_meminfo(struct device *dev,
"Node %d ShadowCallStack:%8lu kB\n"
#endif
"Node %d PageTables: %8lu kB\n"
+ "Node %d SecPageTables: %8lu kB\n"
"Node %d NFS_Unstable: %8lu kB\n"
"Node %d Bounce: %8lu kB\n"
"Node %d WritebackTmp: %8lu kB\n"
@@ -459,6 +460,7 @@ static ssize_t node_read_meminfo(struct device *dev,
nid, node_page_state(pgdat, NR_KERNEL_SCS_KB),
#endif
nid, K(node_page_state(pgdat, NR_PAGETABLE)),
+ nid, K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
nid, 0UL,
nid, K(sum_zone_node_page_state(nid, NR_BOUNCE)),
nid, K(node_page_state(pgdat, NR_WRITEBACK_TEMP)),
diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c
index 6fa761c9cc78..fad29024eb2e 100644
--- a/fs/proc/meminfo.c
+++ b/fs/proc/meminfo.c
@@ -108,6 +108,8 @@ static int meminfo_proc_show(struct seq_file *m, void *v)
#endif
show_val_kb(m, "PageTables: ",
global_node_page_state(NR_PAGETABLE));
+ show_val_kb(m, "SecPageTables: ",
+ global_node_page_state(NR_SECONDARY_PAGETABLE));

show_val_kb(m, "NFS_Unstable: ", 0);
show_val_kb(m, "Bounce: ",
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 962b14d403e8..35f57f2578c0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -219,6 +219,7 @@ 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 shadow pagetables */
#ifdef CONFIG_SWAP
NR_SWAPCACHE,
#endif
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 725f76723220..89fbd1793960 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1388,6 +1388,7 @@ static const struct memory_stat memory_stats[] = {
{ "kernel", MEMCG_KMEM },
{ "kernel_stack", NR_KERNEL_STACK_KB },
{ "pagetables", NR_PAGETABLE },
+ { "secondary_pagetables", NR_SECONDARY_PAGETABLE },
{ "percpu", MEMCG_PERCPU_B },
{ "sock", MEMCG_SOCK },
{ "vmalloc", MEMCG_VMALLOC },
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2db95780e003..96d00ae9d5c1 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5932,7 +5932,8 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
" active_file:%lu inactive_file:%lu isolated_file:%lu\n"
" unevictable:%lu dirty:%lu writeback:%lu\n"
" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
- " mapped:%lu shmem:%lu pagetables:%lu bounce:%lu\n"
+ " mapped:%lu shmem:%lu pagetables:%lu\n"
+ " secondary_pagetables:%lu bounce:%lu\n"
" kernel_misc_reclaimable:%lu\n"
" free:%lu free_pcp:%lu free_cma:%lu\n",
global_node_page_state(NR_ACTIVE_ANON),
@@ -5949,6 +5950,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
global_node_page_state(NR_FILE_MAPPED),
global_node_page_state(NR_SHMEM),
global_node_page_state(NR_PAGETABLE),
+ global_node_page_state(NR_SECONDARY_PAGETABLE),
global_zone_page_state(NR_BOUNCE),
global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE),
global_zone_page_state(NR_FREE_PAGES),
@@ -5982,6 +5984,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
" shadow_call_stack:%lukB"
#endif
" pagetables:%lukB"
+ " secondary_pagetables:%lukB"
" all_unreclaimable? %s"
"\n",
pgdat->node_id,
@@ -6007,6 +6010,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
node_page_state(pgdat, NR_KERNEL_SCS_KB),
#endif
K(node_page_state(pgdat, NR_PAGETABLE)),
+ K(node_page_state(pgdat, NR_SECONDARY_PAGETABLE)),
pgdat->kswapd_failures >= MAX_RECLAIM_RETRIES ?
"yes" : "no");
}
diff --git a/mm/vmstat.c b/mm/vmstat.c
index b75b1a64b54c..50bbec73809b 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1240,6 +1240,7 @@ const char * const vmstat_text[] = {
"nr_shadow_call_stack",
#endif
"nr_page_table_pages",
+ "nr_secondary_page_table_pages",
#ifdef CONFIG_SWAP
"nr_swapcached",
#endif
--
2.36.0.464.gb9c8b46e94-goog