mm: memcontrol: report kernel stack usage in cgroup2 memory.stat

Show how much memory is allocated to kernel stacks.

Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 17 insertions, 2 deletions

diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index e4e0c1d78cee..e2f4e7948a66 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -843,6 +843,10 @@ PAGE_SIZE multiple when read back.
                 Amount of memory used to cache filesystem data,
                 including tmpfs and shared memory.
 
+          kernel_stack
+
+                Amount of memory allocated to kernel stacks.
+
           slab
 
                 Amount of memory used for storing in-kernel data
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index e7af4834ffea..d6300313b298 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -52,9 +52,10 @@ enum mem_cgroup_stat_index {
         MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
         MEM_CGROUP_STAT_NSTATS,
         /* default hierarchy stats */
-        MEMCG_SOCK = MEM_CGROUP_STAT_NSTATS,
+        MEMCG_KERNEL_STACK = MEM_CGROUP_STAT_NSTATS,
         MEMCG_SLAB_RECLAIMABLE,
         MEMCG_SLAB_UNRECLAIMABLE,
+        MEMCG_SOCK,
         MEMCG_NR_STAT,
 };
 
diff --git a/kernel/fork.c b/kernel/fork.c
index 2e391c754ae7..accb7221d547 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -164,12 +164,20 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk,
         struct page *page = alloc_kmem_pages_node(node, THREADINFO_GFP,
                                                   THREAD_SIZE_ORDER);
 
+        if (page)
+                memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,
+                                            1 << THREAD_SIZE_ORDER);
+
         return page ? page_address(page) : NULL;
 }
 
 static inline void free_thread_info(struct thread_info *ti)
 {
-        free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER);
+        struct page *page = virt_to_page(ti);
+
+        memcg_kmem_update_page_stat(page, MEMCG_KERNEL_STACK,
+                                    -(1 << THREAD_SIZE_ORDER));
+        __free_kmem_pages(page, THREAD_SIZE_ORDER);
 }
 # else
 static struct kmem_cache *thread_info_cache;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3ad64bf464fd..4b7dda7c2e74 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5106,6 +5106,8 @@ static int memory_stat_show(struct seq_file *m, void *v)
                    (u64)stat[MEM_CGROUP_STAT_RSS] * PAGE_SIZE);
         seq_printf(m, "file %llu\n",
                    (u64)stat[MEM_CGROUP_STAT_CACHE] * PAGE_SIZE);
+        seq_printf(m, "kernel_stack %llu\n",
+                   (u64)stat[MEMCG_KERNEL_STACK] * PAGE_SIZE);
         seq_printf(m, "slab %llu\n",
                    (u64)(stat[MEMCG_SLAB_RECLAIMABLE] +
                          stat[MEMCG_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);