- 08 Jan, 2009 40 commits
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Daisuke Nishimura authored
mem_cgroup_hierarchicl_reclaim() works properly even when !use_hierarchy now (by memcg-hierarchy-avoid-unnecessary-reclaim.patch), so, instead of try_to_free_mem_cgroup_pages(), it should be used in many cases. The only exception is force_empty. The group has no children in this case. Signed-off-by:
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by:
Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Daisuke Nishimura authored
mpol_rebind_mm(), which can be called from cpuset_attach(), does down_write(mm->mmap_sem). This means down_write(mm->mmap_sem) can be called under cgroup_mutex. OTOH, page fault path does down_read(mm->mmap_sem) and calls mem_cgroup_try_charge_xxx(), which may eventually calls mem_cgroup_out_of_memory(). And mem_cgroup_out_of_memory() calls cgroup_lock(). This means cgroup_lock() can be called under down_read(mm->mmap_sem). If those two paths race, deadlock can happen. This patch avoid this deadlock by: - remove cgroup_lock() from mem_cgroup_out_of_memory(). - define new mutex (memcg_tasklist) and serialize mem_cgroup_move_task() (->attach handler of memory cgroup) and mem_cgroup_out_of_memory. Signed-off-by: -
Daisuke Nishimura authored
After previous patch, mem_cgroup_try_charge is not used by anyone, so we can remove it. Signed-off-by:
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Daisuke Nishimura authored
I think triggering OOM at mem_cgroup_prepare_migration would be just a bit overkill. Returning -ENOMEM would be enough for mem_cgroup_prepare_migration. The caller would handle the case anyway. Signed-off-by:
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KAMEZAWA Hiroyuki authored
Documentation for implementation details and how to test. Just an example. feel free to modify, add, remove lines. Signed-off-by:
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KAMEZAWA Hiroyuki authored
Show "real" limit of memcg. This helps my debugging and maybe useful for users. While testing hierarchy like this mount -t cgroup none /cgroup -t memory mkdir /cgroup/A set use_hierarchy==1 to "A" mkdir /cgroup/A/01 mkdir /cgroup/A/01/02 mkdir /cgroup/A/01/03 mkdir /cgroup/A/01/03/04 mkdir /cgroup/A/08 mkdir /cgroup/A/08/01 .... and set each own limit to them, "real" limit of each memcg is unclear. This patch shows real limit by checking all ancestors. Changelog: (v1) -> (v2) - remove "if" and use "min(a,b)" Acked-by:
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KOSAKI Motohiro authored
Currently, inactive_ratio of memcg is calculated at setting limit. because page_alloc.c does so and current implementation is straightforward porting. However, memcg introduced hierarchy feature recently. In hierarchy restriction, memory limit is not only decided memory.limit_in_bytes of current cgroup, but also parent limit and sibling memory usage. Then, The optimal inactive_ratio is changed frequently. So, everytime calculation is better. Tested-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by:
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KOSAKI Motohiro authored
Currently, /proc/sys/vm/swappiness can change swappiness ratio for global reclaim. However, memcg reclaim doesn't have tuning parameter for itself. In general, the optimal swappiness depend on workload. (e.g. hpc workload need to low swappiness than the others.) Then, per cgroup swappiness improve administrator tunability. Signed-off-by:
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KOSAKI Motohiro authored
Currently, mem_cgroup doesn't have own lock and almost its member doesn't need. (e.g. mem_cgroup->info is protected by zone lock, mem_cgroup->stat is per cpu variable) However, there is one explict exception. mem_cgroup->prev_priorit need lock, but doesn't protect. Luckly, this is NOT bug because prev_priority isn't used for current reclaim code. However, we plan to use prev_priority future again. Therefore, fixing is better. In addition, we plan to reuse this lock for another member. Then "reclaim_param_lock" name is better than "prev_priority_lock". Acked-by:
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KAMEZAWA Hiroyuki authored
Rename scan_global_lru() to scanning_global_lru(). Signed-off-by:
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KOSAKI Motohiro authored
Add the following four fields to memory.stat file: - inactive_ratio - recent_rotated_anon - recent_rotated_file - recent_scanned_anon - recent_scanned_file Acked-by:
Rik van Riel <riel@redhat.com> Signed-off-by:
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KOSAKI Motohiro authored
Now, get_scan_ratio() return correct value although memcg reclaim. Then, mem_cgroup_calc_reclaim() can be removed. So, memcg reclaim get the same capability of anon/file reclaim balancing as global reclaim now. Acked-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@redhat.com> Acked-by:
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KOSAKI Motohiro authored
Introduce mem_cgroup_per_zone::reclaim_stat member and its statics collecting function. Now, get_scan_ratio() can calculate correct value on memcg reclaim. [hugh@veritas.com: avoid reclaim_stat oops when disabled] Acked-by:
Hugh Dickins <hugh@veritas.com> Signed-off-by:
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KOSAKI Motohiro authored
Introduce mem_cgroup_zone_nr_pages(). It is called by zone_nr_pages() helper function. This patch doesn't have any behavior change. Acked-by:
Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by:
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KOSAKI Motohiro authored
The inactive_anon_is_low() is key component of active/inactive anon balancing on reclaim. However current inactive_anon_is_low() function only consider global reclaim. Therefore, we need following ugly scan_global_lru() condition. if (lru == LRU_ACTIVE_ANON && (!scan_global_lru(sc) || inactive_anon_is_low(zone))) { shrink_active_list(nr_to_scan, zone, sc, priority, file); return 0; it cause that memcg reclaim always deactivate pages when shrink_list() is called. To make mem_cgroup_inactive_anon_is_low() improve active/inactive anon balancing of memcgroup. Acked-by: -
KOSAKI Motohiro authored
If CONFIG_CGROUP_MEM_RES_CTLR_SWAP=y, page_cgroup::mem_cgroup can be NULL. Therefore null checking is better. A later patch uses this function. Acked-by:
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KOSAKI Motohiro authored
Currently, get_scan_ratio() always calculate the balancing value for global reclaim and memcg reclaim doesn't use it. Therefore it doesn't have scan_global_lru() condition. However, we plan to expand get_scan_ratio() to be usable for memcg too, latter. Then, The dependency code of global reclaim in the get_scan_ratio() insert into scan_global_lru() condision explictly. This patch doesn't have any functional change. Acked-by:
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KOSAKI Motohiro authored
Add zone_nr_pages() helper function. It is used by a later patch. This patch doesn't have any functional change. Reviewed-by:
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KOSAKI Motohiro authored
Add zone_reclam_stat struct for later enhancement. A later patch uses this. This patch doesn't any behavior change (yet). Reviewed-by:
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KOSAKI Motohiro authored
The inactive_anon_is_low() is called only vmscan. Then it can move to vmscan.c This patch doesn't have any functional change. Reviewd-by:
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Daisuke Nishimura authored
If hierarchy is not used, no tree-walk is necessary. Reviewed-by:
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KAMEZAWA Hiroyuki authored
css's refcnt is dropped before end of following access. Hold it until end of access. Reported-by:
Li Zefan <lizf@cn.fujitsu.com> Signed-off-by:
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Daisuke Nishimura authored
There are scatterd calls of res_counter_check_under_limit(), and most of them don't take mem+swap accounting into account. define mem_cgroup_check_under_limit() and avoid direct use of res_counter_check_limit(). Reported-by:
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Nikanth Karthikesan authored
Remove unnecessary codes (...fragments of not-implemented functionalilty...) Reported-by:
Nikanth Karthikesan <knikanth@suse.de> Signed-off-by:
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KAMEZAWA Hiroyuki authored
My patch, memcg-fix-gfp_mask-of-callers-of-charge.patch changed gfp_mask of callers of charge to be GFP_HIGHUSER_MOVABLE for showing what will happen at memory reclaim. But in recent discussion, it's NACKed because it sounds ugly. This patch is for reverting it and add some clean up to gfp_mask of callers of charge. No behavior change but need review before generating HUNK in deep queue. This patch also adds explanation to meaning of gfp_mask passed to charge functions in memcontrol.h. Signed-off-by:
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KAMEZAWA Hiroyuki authored
check_under_limit logic was wrong and this check should be against mem_over_limit rather than mem. Reported-by:
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KAMEZAWA Hiroyuki authored
Current mmtom has new oom function as pagefault_out_of_memory(). It's added for select bad process rathar than killing current. When memcg hit limit and calls OOM at page_fault, this handler called and system-wide-oom handling happens. (means kernel panics if panic_on_oom is true....) To avoid overkill, check memcg's recent behavior before starting system-wide-oom. And this patch also fixes to guarantee "don't accnout against process with TIF_MEMDIE". This is necessary for smooth OOM. [akpm@linux-foundation.org: build fix] Signed-off-by:
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Lai Jiangshan authored
mm_match_cgroup() calls cgroup_subsys_state(). We must use rcu_read_lock() to protect cgroup_subsys_state(). Signed-off-by:
Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Reviewed-by:
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Balbir Singh authored
Don't enable multiple hierarchy support by default. This patch introduces a features element that can be set to enable the nested depth hierarchy feature. This feature can only be enabled when the cgroup for which the feature this is enabled, has no children. Signed-off-by:
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Balbir Singh authored
This patch introduces hierarchical reclaim. When an ancestor goes over its limit, the charging routine points to the parent that is above its limit. The reclaim process then starts from the last scanned child of the ancestor and reclaims until the ancestor goes below its limit. [akpm@linux-foundation.org: coding-style fixes] [d-nishimura@mtf.biglobe.ne.jp: mem_cgroup_from_res_counter should handle both mem->res and mem->memsw] Signed-off-by:
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Balbir Singh authored
Add support for building hierarchies in resource counters. Cgroups allows us to build a deep hierarchy, but we currently don't link the resource counters belonging to the memory controller control groups, in the same fashion as the corresponding cgroup entries in the cgroup hierarchy. This patch provides the infrastructure for resource counters that have the same hiearchy as their cgroup counter parts. These set of patches are based on the resource counter hiearchy patches posted by Pavel Emelianov. NOTE: Building hiearchies is expensive, deeper hierarchies imply charging the all the way up to the root. It is known that hiearchies are expensive, so the user needs to be careful and aware of the trade-offs before creating very deep ones. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Balbir Singh authored
Documentation updates for hierarchy support Signed-off-by:
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Hirokazu Takahashi authored
We check mem_cgroup is disabled or not by checking mem_cgroup_subsys.disabled. I think it has more references than expected, now. replacing if (mem_cgroup_subsys.disabled) with if (mem_cgroup_disabled()) give us good look, I think. [kamezawa.hiroyu@jp.fujitsu.com: fix typo] Signed-off-by:
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KAMEZAWA Hiroyuki authored
A big patch for changing memcg's LRU semantics. Now, - page_cgroup is linked to mem_cgroup's its own LRU (per zone). - LRU of page_cgroup is not synchronous with global LRU. - page and page_cgroup is one-to-one and statically allocated. - To find page_cgroup is on what LRU, you have to check pc->mem_cgroup as - lru = page_cgroup_zoneinfo(pc, nid_of_pc, zid_of_pc); - SwapCache is handled. And, when we handle LRU list of page_cgroup, we do following. pc = lookup_page_cgroup(page); lock_page_cgroup(pc); .....................(1) mz = page_cgroup_zoneinfo(pc); spin_lock(&mz->lru_lock); .....add to LRU spin_unlock(&mz->lru_lock); unlock_page_cgroup(pc); But (1) is spin_lock and we have to be afraid of dead-lock with zone->lru_lock. So, trylock() is used at (1), now. Without (1), we can't trust "mz" is correct. This is a trial to remove this dirty nesting of locks. This patch changes mz->lru_lock to be zone->lru_lock. Then, above sequence will be written as spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU mem_cgroup_add/remove/etc_lru() { pc = lookup_page_cgroup(page); mz = page_cgroup_zoneinfo(pc); if (PageCgroupUsed(pc)) { ....add to LRU } spin_lock(&zone->lru_lock); # in vmscan.c or swap.c via global LRU This is much simpler. (*) We're safe even if we don't take lock_page_cgroup(pc). Because.. 1. When pc->mem_cgroup can be modified. - at charge. - at account_move(). 2. at charge the PCG_USED bit is not set before pc->mem_cgroup is fixed. 3. at account_move() the page is isolated and not on LRU. Pros. - easy for maintenance. - memcg can make use of laziness of pagevec. - we don't have to duplicated LRU/Active/Unevictable bit in page_cgroup. - LRU status of memcg will be synchronized with global LRU's one. - # of locks are reduced. - account_move() is simplified very much. Cons. - may increase cost of LRU rotation. (no impact if memcg is not configured.) Signed-off-by: -
KAMEZAWA Hiroyuki authored
This patch implements per cgroup limit for usage of memory+swap. However there are SwapCache, double counting of swap-cache and swap-entry is avoided. Mem+Swap controller works as following. - memory usage is limited by memory.limit_in_bytes. - memory + swap usage is limited by memory.memsw_limit_in_bytes. This has following benefits. - A user can limit total resource usage of mem+swap. Without this, because memory resource controller doesn't take care of usage of swap, a process can exhaust all the swap (by memory leak.) We can avoid this case. And Swap is shared resource but it cannot be reclaimed (goes back to memory) until it's used. This characteristic can be trouble when the memory is divided into some parts by cpuset or memcg. Assume group A and group B. After some application executes, the system can be.. Group A -- very large free memory space but occupy 99% of swap. Group B -- under memory shortage but cannot use swap...it's nearly full. Ability to set appropriate swap limit for each group is required. Maybe someone wonder "why not swap but mem+swap ?" - The global LRU(kswapd) can swap out arbitrary pages. Swap-out means to move account from memory to swap...there is no change in usage of mem+swap. In other words, when we want to limit the usage of swap without affecting global LRU, mem+swap limit is better than just limiting swap. Accounting target information is stored in swap_cgroup which is per swap entry record. Charge is done as following. map - charge page and memsw. unmap - uncharge page/memsw if not SwapCache. swap-out (__delete_from_swap_cache) - uncharge page - record mem_cgroup information to swap_cgroup. swap-in (do_swap_page) - charged as page and memsw. record in swap_cgroup is cleared. memsw accounting is decremented. swap-free (swap_free()) - if swap entry is freed, memsw is uncharged by PAGE_SIZE. There are people work under never-swap environments and consider swap as something bad. For such people, this mem+swap controller extension is just an overhead. This overhead is avoided by config or boot option. (see Kconfig. detail is not in this patch.) TODO: - maybe more optimization can be don in swap-in path. (but not very safe.) But we just do simple accounting at this stage. [nishimura@mxp.nes.nec.co.jp: make resize limit hold mutex] [hugh@veritas.com: memswap controller core swapcache fixes] Signed-off-by: -
KAMEZAWA Hiroyuki authored
For accounting swap, we need a record per swap entry, at least. This patch adds following function. - swap_cgroup_swapon() .... called from swapon - swap_cgroup_swapoff() ... called at the end of swapoff. - swap_cgroup_record() .... record information of swap entry. - swap_cgroup_lookup() .... lookup information of swap entry. This patch just implements "how to record information". No actual method for limit the usage of swap. These routine uses flat table to record and lookup. "wise" lookup system like radix-tree requires requires memory allocation at new records but swap-out is usually called under memory shortage (or memcg hits limit.) So, I used static allocation. (maybe dynamic allocation is not very hard but it adds additional memory allocation in memory shortage path.) Note1: In this, we use pointer to record information and this means 8bytes per swap entry. I think we can reduce this when we create "id of cgroup" in the range of 0-65535 or 0-255. Reported-by: -
KAMEZAWA Hiroyuki authored
Config and control variable for mem+swap controller. This patch adds CONFIG_CGROUP_MEM_RES_CTLR_SWAP (memory resource controller swap extension.) For accounting swap, it's obvious that we have to use additional memory to remember "who uses swap". This adds more overhead. So, it's better to offer "choice" to users. This patch adds 2 choices. This patch adds 2 parameters to enable swap extension or not. - CONFIG - boot option Reviewed-by:
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KAMEZAWA Hiroyuki authored
SwapCache support for memory resource controller (memcg) Before mem+swap controller, memcg itself should handle SwapCache in proper way. This is cut-out from it. In current memcg, SwapCache is just leaked and the user can create tons of SwapCache. This is a leak of account and should be handled. SwapCache accounting is done as following. charge (anon) - charged when it's mapped. (because of readahead, charge at add_to_swap_cache() is not sane) uncharge (anon) - uncharged when it's dropped from swapcache and fully unmapped. means it's not uncharged at unmap. Note: delete from swap cache at swap-in is done after rmap information is established. charge (shmem) - charged at swap-in. this prevents charge at add_to_page_cache(). uncharge (shmem) - uncharged when it's dropped from swapcache and not on shmem's radix-tree. at migration, check against 'old page' is modified to handle shmem. Comparing to the old version discussed (and caused troubles), we have advantages of - PCG_USED bit. - simple migrating handling. So, situation is much easier than several months ago, maybe. [hugh@veritas.com: memcg: handle swap caches build fix] Reviewed-by:
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KAMEZAWA Hiroyuki authored
By memcg-move-all-accounts-to-parent-at-rmdir.patch, there is no leak of memory usage and force_empty is removed. This patch adds "force_empty" again, in reasonable manner. memory.force_empty file works when #echo 0 (or some) > memory.force_empty and have following function. 1. only works when there are no task in this cgroup. 2. free all page under this cgroup as much as possible. 3. page which cannot be freed will be moved up to parent. 4. Then, memcg will be empty after above echo returns. This is much better behavior than old "force_empty" which just forget all accounts. This patch also check signal_pending() and above "echo" can be stopped by "Ctrl-C". [akpm@linux-foundation.org: cleanup] Signed-off-by:
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Jan Blunck authored
As Jan Blunck <jblunck@suse.de> pointed out, allocating per-cpu stat for memcg to the size of NR_CPUS is not good. This patch changes mem_cgroup's cpustat allocation not based on NR_CPUS but based on nr_cpu_ids. Reviewed-by:
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