admin-guide/cgroup-v1/memory.rst

46  - accounting anonymous pages, file caches, swap caches usage and limiting them.
48  - optionally, memory+swap usage can be accounted and limited.
71  memory.memsw.usage_in_bytes	     show current usage for memory+Swap
74  memory.memsw.limit_in_bytes	     set/show limit of memory+Swap usage
76  memory.memsw.failcnt		     show the number of memory+Swap hits limits
78  memory.memsw.max_usage_in_bytes     show max memory+Swap usage recorded
229 Since page's memcg recorded into swap whatever memsw enabled, the page will
250 2.4 Swap Extension
253 Swap usage is always recorded for each of cgroup. Swap Extension allows you to
261 memsw means memory+swap. Usage of memory+swap is limited by
264 Example: Assume a system with 4G of swap. A task which allocates 6G of memory
265 (by mistake) under 2G memory limitation will use all swap.
266 In this case, setting memsw.limit_in_bytes=3G will prevent bad use of swap.
267 By using the memsw limit, you can avoid system OOM which can be caused by swap
270 2.4.1 why 'memory+swap' rather than swap
273 The global LRU(kswapd) can swap out arbitrary pages. Swap-out means
274 to move account from memory to swap...there is no change in usage of
275 memory+swap. In other words, when we want to limit the usage of swap without
276 affecting global LRU, memory+swap limit is better than just limiting swap from
282 When a cgroup hits memory.memsw.limit_in_bytes, it's useless to do swap-out
283 in this cgroup. Then, swap-out will not be done by cgroup routine and file
493 2. The user is using anonymous memory and swap is turned off or too low
527 Charges recorded in swap information is not updated at removal of cgroup.
528 Recorded information is discarded and a cgroup which uses swap (swapcache)
557     rss             # of bytes of anonymous and swap cache memory (includes
567     swap            # of bytes of swap usage
568     swapcached      # of bytes of swap cached in memory
572     inactive_anon   # of bytes of anonymous and swap cache memory on inactive
574     active_anon     # of bytes of anonymous and swap cache memory on active
588     hierarchical_memsw_limit  # of bytes of memory+swap limit with regard to
612 	Only anonymous and swap cache memory is listed as part of 'rss' stat.
630 there is a swap storage available. This might lead to memcg OOM killer
650 method and doesn't show 'exact' value of memory (and swap) usage, it's a fuzz
652 If you want to know more exact memory usage, you should use RSS+CACHE(+SWAP)
807 a page or a swap can be moved only when it is charged to the task's current
813 | 0 | A charge of an anonymous page (or swap of it) used by the target task.   |
814 |   | You must enable Swap Extension (see 2.4) to enable move of swap charges. |
822 |   | of the mapcount). You must enable Swap Extension (see 2.4) to            |
823 |   | enable move of swap charges.                                             |
920 pressure, the system might be making swap, paging out active file caches,