admin-guide/cgroup-v1/memcg_test.rst

10 is complex. This is a document for memcg's internal behavior.
28    The page_cgroup has USED bit and double count against a page_cgroup never
29    occurs. swap_cgroup is used only when a charged page is swapped-out.
34    a page/swp_entry may be charged (usage += PAGE_SIZE) at
41   a page/swp_entry may be uncharged (usage -= PAGE_SIZE) by
44 	  Called when a page's refcount goes down to 0.
47 	  Called when swp_entry's refcnt goes down to 0. A charge against swap
77 	(a) If the SwapCache is newly allocated and read, it has no charges.
84 	(a) add to swap cache. (marked as SwapCache)
126 	- A new page is added to shmem's radix-tree.
127 	- A swp page is read. (move a charge from swap_cgroup to page_cgroup)
138 	each LRU handled under a single lru_lock for that memcg and node.
166 	is useful. Following is a sample script to do migration::
170 		mkdir /opt/cpuset/01
171 		echo 1 > /opt/cpuset/01/cpuset.cpus
172 		echo 0 > /opt/cpuset/01/cpuset.mems
173 		echo 1 > /opt/cpuset/01/cpuset.memory_migrate
179 	In above set, when you moves a task from 01 to 02, page migration to
180 	node 0 to node 1 will occur. Following is a script to migrate all
218 		mkdir /opt/cgroup/01/child_a
219 		mkdir /opt/cgroup/01/child_b
221 		set limit to 01.
222 		add limit to 01/child_b
227 		/opt/cgroup/01/child_a/child_aa
228 		/opt/cgroup/01/child_b/child_bb
229 		/opt/cgroup/01/child_c
236 	Mounting with other subsystems is a good test because there is a
254 	(Shell-A)::
266 		# /sbin/swapoff -a
276 	the memcg. When hierarchy is used, a task under hierarchy
284 	Case A) when you can swapoff::
286 		#swapoff -a
301 	Charges associated with a task can be moved along with task migration.
303 	(Shell-A)::
305 		#mkdir /cgroup/A
306 		#echo $$ >/cgroup/A/tasks
308 	run some programs which uses some amount of memory in /cgroup/A.
314 		#echo "pid of the program running in group A" >/cgroup/B/tasks
317 	memory.stat of both A and B.
328 	(Shell-A) Create cgroup and run event listener::
330 		# mkdir /cgroup/A
331 		# ./cgroup_event_listener /cgroup/A/memory.usage_in_bytes 5M
335 		# echo $$ >/cgroup/A/tasks
336 		# a="$(dd if=/dev/zero bs=1M count=10)"
337 		# a=
342 	Use /cgroup/A/memory.memsw.usage_in_bytes to test memsw thresholds.