mm: add kernel_misc_reclaimable in show_free_areas

Print NR_KERNEL_MISC_RECLAIMABLE stat from show_free_areas() so users can
check whether the shrinker is working correctly and to show the current
memory usage.

Link: https://lkml.kernel.org/r/20210813104725.4562-1-liuhailong@oppo.comSigned-off-by: Nliuhailong <liuhailong@oppo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -5903,6 +5903,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		" unevictable:%lu dirty:%lu writeback:%lu\n"
 		" slab_reclaimable:%lu slab_unreclaimable:%lu\n"
 		" mapped:%lu shmem:%lu 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),
 		global_node_page_state(NR_INACTIVE_ANON),
@@ -5919,6 +5920,7 @@ void show_free_areas(unsigned int filter, nodemask_t *nodemask)
 		global_node_page_state(NR_SHMEM),
 		global_node_page_state(NR_PAGETABLE),
 		global_zone_page_state(NR_BOUNCE),
+		global_node_page_state(NR_KERNEL_MISC_RECLAIMABLE),
 		global_zone_page_state(NR_FREE_PAGES),
 		free_pcp,
 		global_zone_page_state(NR_FREE_CMA_PAGES));