Lines Matching +full:enable +full:- +full:charge +full:- +full:control
18 we call it "memory cgroup". When you see git-log and source code, you'll
30 Memory-hungry applications can be isolated and limited to a smaller
34 c. Virtualization solutions can control the amount of memory they want
36 d. A CD/DVD burner could control the amount of memory used by the
42 Current Status: linux-2.6.34-mmotm(development version of 2010/April)
46 - accounting anonymous pages, file caches, swap caches usage and limiting them.
47 - pages are linked to per-memcg LRU exclusively, and there is no global LRU.
48 - optionally, memory+swap usage can be accounted and limited.
49 - hierarchical accounting
50 - soft limit
51 - moving (recharging) account at moving a task is selectable.
52 - usage threshold notifier
53 - memory pressure notifier
54 - oom-killer disable knob and oom-notifier
55 - Root cgroup has no limit controls.
59 <cgroup-v1-memory-kernel-extension>`)
61 Brief summary of control files.
133 there were several implementations for memory control. The goal of the
135 for memory control. The first RSS controller was posted by Balbir Singh [2]_
141 Cache Control [11]_.
143 2. Memory Control
156 3. Kernel user memory accounting and slab control
162 -----------
170 ---------------
172 .. code-block::
175 +--------------------+
178 +--------------------+
181 +---------------+ | +---------------+
184 +---------------+ | +---------------+
186 + --------------+
188 +---------------+ +------+--------+
189 | page +----------> page_cgroup|
191 +---------------+ +---------------+
206 If everything goes well, a page meta-data-structure called page_cgroup is
208 (*) page_cgroup structure is allocated at boot/memory-hotplug time.
211 ------------------------
226 A swapped-in page is accounted after adding into swapcache.
228 Note: The kernel does swapin-readahead and reads multiple swaps at once.
234 Note: we just account pages-on-LRU because our purpose is to control amount
235 of used pages; not-on-LRU pages tend to be out-of-control from VM view.
238 --------------------------
244 the cgroup that brought it in -- this will happen on memory pressure).
246 But see :ref:`section 8.2 <cgroup-v1-memory-movable-charges>` when moving a
251 --------------------------------------
258 - memory.memsw.usage_in_bytes.
259 - memory.memsw.limit_in_bytes.
273 The global LRU(kswapd) can swap out arbitrary pages. Swap-out means
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
289 -----------
296 cgroup. (See :ref:`10. OOM Control <cgroup-v1-memory-oom-control>` below.)
299 pages that are selected for reclaiming come from the per-cgroup LRU
310 (See :ref:`oom_control <cgroup-v1-memory-oom-control>` section)
313 -----------
318 mm->page_table_lock or split pte_lock
319 folio_memcg_lock (memcg->move_lock)
320 mapping->i_pages lock
321 lruvec->lru_lock.
323 Per-node-per-memcgroup LRU (cgroup's private LRU) is guarded by
324 lruvec->lru_lock; the folio LRU flag is cleared before
325 isolating a page from its LRU under lruvec->lru_lock.
327 .. _cgroup-v1-memory-kernel-extension:
330 -----------------------------------------------
338 it can be disabled system-wide by passing cgroup.memory=nokmem to the kernel
353 -----------------------------------------------
377 ----------------------
390 deployments where the total amount of memory per-cgroup is overcommitted.
392 box can still run out of non-reclaimable memory.
413 1. Enable CONFIG_CGROUPS and CONFIG_MEMCG options
415 <cgroups-why-needed>` for the background information)::
417 # mount -t tmpfs none /sys/fs/cgroup
419 # mount -t cgroup none /sys/fs/cgroup/memory -o memory
441 We can write "-1" to reset the ``*.limit_in_bytes(unlimited)``.
455 availability of memory on the system. The user is required to re-read
477 Page-fault scalability is also important. At measuring parallel
478 page fault test, multi-process test may be better than multi-thread
484 .. _cgroup-v1-memory-test-troubleshoot:
487 -------------------
498 To know what happens, disabling OOM_Kill as per :ref:`"10. OOM Control"
499 <cgroup-v1-memory-oom-control>` (below) and seeing what happens will be
502 .. _cgroup-v1-memory-test-task-migration:
505 ------------------
507 When a task migrates from one cgroup to another, its charge is not
509 remain charged to it, the charge is dropped when the page is freed or
513 See :ref:`8. "Move charges at task migration" <cgroup-v1-memory-move-charges>`
516 ---------------------
519 <cgroup-v1-memory-test-troubleshoot>` and :ref:`4.2
520 <cgroup-v1-memory-test-task-migration>`, a cgroup might have some charge
522 we charge against pages, not against tasks.)
524 We move the stats to parent, and no change on the charge except uncharging
535 ---------------
545 charged file caches. Some out-of-use page caches may keep charged until
549 -------------
553 * per-memory cgroup local status
576 inactive_file # of bytes of file-backed memory and MADV_FREE anonymous
578 active_file # of bytes of file-backed memory on active LRU list.
623 --------------
634 -----------
646 ------------------
656 -------------
658 This is similar to numa_maps but operates on a per-memcg basis. This is
665 per-node page counts including "hierarchical_<counter>" which sums up all
700 ---------------------------------------
716 is to allow control groups to use as much of the memory as needed, provided
721 When the system detects memory contention or low memory, control groups
722 are pushed back to their soft limits. If the soft limit of each control
724 sure that one control group does not starve the others of memory.
726 Please note that soft limits is a best-effort feature; it comes with
733 -------------
752 .. _cgroup-v1-memory-move-charges:
761 cgroups to allow fine-grained policy adjustments without having to
762 move physical pages between control domains.
765 is, uncharge task's pages from the old cgroup and charge them to the new cgroup.
770 -------------
775 If you want to enable it::
782 <cgroup-v1-memory-movable-charges>` for details.
785 Charges are moved only when you move mm->owner, in other words,
800 .. _cgroup-v1-memory-movable-charges:
803 --------------------------------------
810 +---+--------------------------------------------------------------------------+
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. |
815 +---+--------------------------------------------------------------------------+
816 | 1 | A charge of file pages (normal file, tmpfs file (e.g. ipc shared memory) |
822 | | of the mapcount). You must enable Swap Extension (see 2.4) to |
823 | | enable move of swap charges. |
824 +---+--------------------------------------------------------------------------+
827 --------
829 - All of moving charge operations are done under cgroup_mutex. It's not good
841 - create an eventfd using eventfd(2);
842 - open memory.usage_in_bytes or memory.memsw.usage_in_bytes;
843 - write string like "<event_fd> <fd of memory.usage_in_bytes> <threshold>" to
849 It's applicable for root and non-root cgroup.
851 .. _cgroup-v1-memory-oom-control:
853 10. OOM Control (DEPRECATED)
866 - create an eventfd using eventfd(2)
867 - open memory.oom_control file
868 - write string like "<event_fd> <fd of memory.oom_control>" to
874 You can disable the OOM-killer by writing "1" to memory.oom_control file, as:
878 If OOM-killer is disabled, tasks under cgroup will hang/sleep
879 in memory cgroup's OOM-waitqueue when they request accountable memory.
895 - oom_kill_disable 0 or 1
896 (if 1, oom-killer is disabled)
897 - under_oom 0 or 1
899 - oom_kill integer counter
923 resources that can be easily reconstructed or re-read from a disk.
926 about to out of memory (OOM) or even the in-kernel OOM killer is on its
932 events are not pass-through. For example, you have three cgroups: A->B->C. Now
942 - "default": this is the default behavior specified above. This mode is the
946 - "hierarchy": events always propagate up to the root, similar to the default
951 - "local": events are pass-through, i.e. they only receive notifications when
960 specified by a comma-delimited string, i.e. "low,hierarchy" specifies
961 hierarchical, pass-through, notification for all ancestor memcgs. Notification
962 that is the default, non pass-through behavior, does not specify a mode.
963 "medium,local" specifies pass-through notification for the medium level.
968 - create an eventfd using eventfd(2);
969 - open memory.pressure_level;
970 - write string as "<event_fd> <fd of memory.pressure_level> <level[,mode]>"
992 (Expect a bunch of notifications, and eventually, the oom-killer will
998 1. Make per-cgroup scanner reclaim not-shared pages first
999 2. Teach controller to account for shared-pages
1013 .. [2] Singh, Balbir. Memory Controller (RSS Control),
1022 6. Menage, Paul. Control Groups v10, http://lwn.net/Articles/236032/
1023 7. Vaidyanathan, Srinivasan, Control Groups: Pagecache accounting and control
1030 https://lore.kernel.org/r/20070819094658.654.84837.sendpatchset@balbir-laptop
1033 https://lore.kernel.org/r/20070817084228.26003.12568.sendpatchset@balbir-laptop