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Date:   Fri, 29 Apr 2022 20:11:28 +0000
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Subject: [PATCH v4 1/4] mm: add NR_SECONDARY_PAGETABLE to count secondary page
 table uses.
From:   Yosry Ahmed <yosryahmed@google.com>
To:     Tejun Heo <tj@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>,
        Zefan Li <lizefan.x@bytedance.com>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Oliver Upton <oupton@google.com>
Cc:     cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        kvm@vger.kernel.org, linux-mm@kvack.org,
        Yosry Ahmed <yosryahmed@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

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