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* memcg: generic filestat update interfaceKAMEZAWA Hiroyuki2010-10-281-7/+18
| | | | | | | | | | | | | | | | | | | This patch extracts the core logic from mem_cgroup_update_file_mapped() as mem_cgroup_update_file_stat() and adds a wrapper. As a planned future update, memory cgroup has to count dirty pages to implement dirty_ratio/limit. And more, the number of dirty pages is required to kick flusher thread to start writeback. (Now, no kick.) This patch is preparation for it and makes other statistics implementation clearer. Just a clean up. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Greg Thelen <gthelen@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: cpu hotplug aware quick acount_move detectionKAMEZAWA Hiroyuki2010-10-281-7/+30
| | | | | | | | | | | | | | | | An event counter MEM_CGROUP_ON_MOVE is used for quick check whether file stat update can be done in async manner or not. Now, it use percpu counter and for_each_possible_cpu to update. This patch replaces for_each_possible_cpu to for_each_online_cpu and adds necessary synchronization logic at CPU HOTPLUG. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: cpu hotplug aware percpu count updatesKAMEZAWA Hiroyuki2010-10-281-9/+93
| | | | | | | | | | | | | | | Now, memcgroup's per cpu coutner uses for_each_possible_cpu() to get the value. It's better to use for_each_online_cpu() and a cpu hotplug handler. This patch only handles statistics counter. MEM_CGROUP_ON_MOVE will be handled in another patch. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: use for_each_mem_cgroupKAMEZAWA Hiroyuki2010-10-281-87/+83
| | | | | | | | | | | | | | | | | | | | | | | | | | | | In memory cgroup management, we sometimes have to walk through subhierarchy of cgroup to gather informaiton, or lock something, etc. Now, to do that, mem_cgroup_walk_tree() function is provided. It calls given callback function per cgroup found. But the bad thing is that it has to pass a fixed style function and argument, "void*" and it adds much type casting to memcontrol.c. To make the code clean, this patch replaces walk_tree() with for_each_mem_cgroup_tree(iter, root) An iterator style call. The good point is that iterator call doesn't have to assume what kind of function is called under it. A bad point is that it may cause reference-count leak if a caller use "break" from the loop by mistake. I think the benefit is larger. The modified code seems straigtforward and easy to read because we don't have misterious callbacks and pointer cast. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: avoid lock in updating file_mapped (Was fix race in file_mapped ↵KAMEZAWA Hiroyuki2010-10-281-14/+85
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | accouting flag management At accounting file events per memory cgroup, we need to find memory cgroup via page_cgroup->mem_cgroup. Now, we use lock_page_cgroup() for guarantee pc->mem_cgroup is not overwritten while we make use of it. But, considering the context which page-cgroup for files are accessed, we can use alternative light-weight mutual execusion in the most case. At handling file-caches, the only race we have to take care of is "moving" account, IOW, overwriting page_cgroup->mem_cgroup. (See comment in the patch) Unlike charge/uncharge, "move" happens not so frequently. It happens only when rmdir() and task-moving (with a special settings.) This patch adds a race-checker for file-cache-status accounting v.s. account moving. The new per-cpu-per-memcg counter MEM_CGROUP_ON_MOVE is added. The routine for account move 1. Increment it before start moving 2. Call synchronize_rcu() 3. Decrement it after the end of moving. By this, file-status-counting routine can check it needs to call lock_page_cgroup(). In most case, I doesn't need to call it. Following is a perf data of a process which mmap()/munmap 32MB of file cache in a minute. Before patch: 28.25% mmap mmap [.] main 22.64% mmap [kernel.kallsyms] [k] page_fault 9.96% mmap [kernel.kallsyms] [k] mem_cgroup_update_file_mapped 3.67% mmap [kernel.kallsyms] [k] filemap_fault 3.50% mmap [kernel.kallsyms] [k] unmap_vmas 2.99% mmap [kernel.kallsyms] [k] __do_fault 2.76% mmap [kernel.kallsyms] [k] find_get_page After patch: 30.00% mmap mmap [.] main 23.78% mmap [kernel.kallsyms] [k] page_fault 5.52% mmap [kernel.kallsyms] [k] mem_cgroup_update_file_mapped 3.81% mmap [kernel.kallsyms] [k] unmap_vmas 3.26% mmap [kernel.kallsyms] [k] find_get_page 3.18% mmap [kernel.kallsyms] [k] __do_fault 3.03% mmap [kernel.kallsyms] [k] filemap_fault 2.40% mmap [kernel.kallsyms] [k] handle_mm_fault 2.40% mmap [kernel.kallsyms] [k] do_page_fault This patch reduces memcg's cost to some extent. (mem_cgroup_update_file_mapped is called by both of map/unmap) Note: It seems some more improvements are required..but no idea. maybe removing set/unset flag is required. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix race in file_mapped accouting flag managementKAMEZAWA Hiroyuki2010-10-281-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Presently memory cgroup accounts file-mapped by counter and flag. counter is working in the same way with zone_stat but FileMapped flag only exists in memcg (for helping move_account). This flag can be updated wrongly in a case. Assume CPU0 and CPU1 and a thread mapping a page on CPU0, another thread unmapping it on CPU1. CPU0 CPU1 rmv rmap (mapcount 1->0) add rmap (mapcount 0->1) lock_page_cgroup() memcg counter+1 (some delay) set MAPPED FLAG. unlock_page_cgroup() lock_page_cgroup() memcg counter-1 clear MAPPED flag In the above sequence counter is properly updated but FLAG is not. This means that representing a state by a flag which is maintained by counter needs some special care. To handle this, when clearing a flag, this patch check mapcount directly and clear the flag only when mapcount == 0. (if mapcount >0, someone will make it to zero later and flag will be cleared.) Reverse case, dec-after-inc cannot be a problem because page_table_lock() works well for it. (IOW, to make above sequence, 2 processes should touch the same page at once with map/unmap.) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Greg Thelen <gthelen@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix thresholds with use_hierarchy == 1Kirill A. Shutemov2010-10-071-3/+7
| | | | | | | | | | | | | We need to check parent's thresholds if parent has use_hierarchy == 1 to be sure that parent's threshold events will be triggered even if parent itself is not active (no MEM_CGROUP_EVENTS). Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Reviewed-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>
* memcg: convert to use zone_to_nid() from bare zone->zone_pgdat->node_idKOSAKI Motohiro2010-08-111-3/+3
| | | | | | | | | | | | | We have zone_to_nid(). this patch convert all existing users of zone->zone_pgdat->node_id. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: remove nid and zid argument from mem_cgroup_soft_limit_reclaim()KOSAKI Motohiro2010-08-111-3/+2
| | | | | | | | | | | | | mem_cgroup_soft_limit_reclaim() has zone, nid and zid argument. but nid and zid can be calculated from zone. So remove it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: mem_cgroup_shrink_node_zone() doesn't need sc.nodemaskKOSAKI Motohiro2010-08-111-2/+1
| | | | | | | | | | | | | | Currently mem_cgroup_shrink_node_zone() call shrink_zone() directly. thus it doesn't need to initialize sc.nodemask because shrink_zone() doesn't use it at all. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Nishimura Daisuke <d-nishimura@mtf.biglobe.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: avoid css_get()KAMEZAWA Hiroyuki2010-08-111-43/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now, memory cgroup increments css(cgroup subsys state)'s reference count per a charged page. And the reference count is kept until the page is uncharged. But this has 2 bad effect. 1. Because css_get/put calls atomic_inc()/dec, heavy call of them on large smp will not scale well. 2. Because css's refcnt cannot be in a state as "ready-to-release", cgroup's notify_on_release handler can't work with memcg. 3. css's refcnt is atomic_t, it means smaller than 32bit. Maybe too small. This has been a problem since the 1st merge of memcg. This is a trial to remove css's refcnt per a page. Even if we remove refcnt, pre_destroy() does enough synchronization as - check res->usage == 0. - check no pages on LRU. This patch removes css's refcnt per page. Even after this patch, at the 1st look, it seems css_get() is still called in try_charge(). But the logic is. - If a memcg of mm->owner is cached one, consume_stock() will work. At success, return immediately. - If consume_stock returns false, css_get() is called and go to slow path which may be blocked. At the end of slow path, css_put() is called and restart from the start if necessary. So, in the fast path, we don't call css_get() and can avoid access to shared counter. This patch can make the most possible case fast. Here is a result of multi-threaded page fault benchmark. [Before] 25.32% multi-fault-all [kernel.kallsyms] [k] clear_page_c 9.30% multi-fault-all [kernel.kallsyms] [k] _raw_spin_lock_irqsave 8.02% multi-fault-all [kernel.kallsyms] [k] try_get_mem_cgroup_from_mm <=====(*) 7.83% multi-fault-all [kernel.kallsyms] [k] down_read_trylock 5.38% multi-fault-all [kernel.kallsyms] [k] __css_put 5.29% multi-fault-all [kernel.kallsyms] [k] __alloc_pages_nodemask 4.92% multi-fault-all [kernel.kallsyms] [k] _raw_spin_lock_irq 4.24% multi-fault-all [kernel.kallsyms] [k] up_read 3.53% multi-fault-all [kernel.kallsyms] [k] css_put 2.11% multi-fault-all [kernel.kallsyms] [k] handle_mm_fault 1.76% multi-fault-all [kernel.kallsyms] [k] __rmqueue 1.64% multi-fault-all [kernel.kallsyms] [k] __mem_cgroup_commit_charge [After] 28.41% multi-fault-all [kernel.kallsyms] [k] clear_page_c 10.08% multi-fault-all [kernel.kallsyms] [k] _raw_spin_lock_irq 9.58% multi-fault-all [kernel.kallsyms] [k] down_read_trylock 9.38% multi-fault-all [kernel.kallsyms] [k] _raw_spin_lock_irqsave 5.86% multi-fault-all [kernel.kallsyms] [k] __alloc_pages_nodemask 5.65% multi-fault-all [kernel.kallsyms] [k] up_read 2.82% multi-fault-all [kernel.kallsyms] [k] handle_mm_fault 2.64% multi-fault-all [kernel.kallsyms] [k] mem_cgroup_add_lru_list 2.48% multi-fault-all [kernel.kallsyms] [k] __mem_cgroup_commit_charge Then, 8.02% of try_get_mem_cgroup_from_mm() disappears because this patch removes css_tryget() in it. (But yes, this is an extreme case.) Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: use find_lock_task_mm() in memory cgroups oomKAMEZAWA Hiroyuki2010-08-111-3/+7
| | | | | | | | | | | | | | | | | When the OOM killer scans task, it check a task is under memcg or not when it's called via memcg's context. But, as Oleg pointed out, a thread group leader may have NULL ->mm and task_in_mem_cgroup() may do wrong decision. We have to use find_lock_task_mm() in memcg as generic OOM-Killer does. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: remove mem from arg of charge_commonDaisuke Nishimura2010-08-111-9/+8
| | | | | | | | | | | mem_cgroup_charge_common() is always called with @mem = NULL, so it's meaningless. This patch removes it. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: remove redundant codeDaisuke Nishimura2010-08-111-10/+0
| | | | | | | | | | | | | | | | - try_get_mem_cgroup_from_mm() calls rcu_read_lock/unlock by itself, so we don't have to call them in task_in_mem_cgroup(). - *mz is not used in __mem_cgroup_uncharge_common(). - we don't have to call lookup_page_cgroup() in mem_cgroup_end_migration() after we've cleared PCG_MIGRATION of @oldpage. - remove empty comment. - remove redundant empty line in mem_cgroup_cache_charge(). Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: clean up waiting move acctKAMEZAWA Hiroyuki2010-08-111-22/+29
| | | | | | | | | | | | | | | | | | Now, for checking a memcg is under task-account-moving, we do css_tryget() against mc.to and mc.from. But this is just complicating things. This patch makes the check easier. This patch adds a spinlock to move_charge_struct and guard modification of mc.to and mc.from. By this, we don't have to think about complicated races arount this not-critical path. [balbir@linux.vnet.ibm.com: don't crash on a null memcg being passed] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: clean up try_charge main loopKAMEZAWA Hiroyuki2010-08-111-100/+148
| | | | | | | | | | | | | | | | | | | mem_cgroup_try_charge() has a big loop in it and seems to be hard to read. Most of routines are for slow path. This patch moves codes out from the loop and make it clear what's done. Summary: - refactoring a function to detect a memcg is under acccount move or not. - refactoring a function to wait for the end of moving task acct. - refactoring a main loop('s slow path) as a function and make it clear why we retry or quit by return code. - add fatal_signal_pending() check for bypassing charge loops. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: add mm_vmscan_memcg_isolate tracepointKOSAKI Motohiro2010-08-101-0/+6
| | | | | | | | | | | | Memcg also need to trace page isolation information as global reclaim. This patch does it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> 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>
* oom: badness heuristic rewriteDavid Rientjes2010-08-101-0/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This a complete rewrite of the oom killer's badness() heuristic which is used to determine which task to kill in oom conditions. The goal is to make it as simple and predictable as possible so the results are better understood and we end up killing the task which will lead to the most memory freeing while still respecting the fine-tuning from userspace. Instead of basing the heuristic on mm->total_vm for each task, the task's rss and swap space is used instead. This is a better indication of the amount of memory that will be freeable if the oom killed task is chosen and subsequently exits. This helps specifically in cases where KDE or GNOME is chosen for oom kill on desktop systems instead of a memory hogging task. The baseline for the heuristic is a proportion of memory that each task is currently using in memory plus swap compared to the amount of "allowable" memory. "Allowable," in this sense, means the system-wide resources for unconstrained oom conditions, the set of mempolicy nodes, the mems attached to current's cpuset, or a memory controller's limit. The proportion is given on a scale of 0 (never kill) to 1000 (always kill), roughly meaning that if a task has a badness() score of 500 that the task consumes approximately 50% of allowable memory resident in RAM or in swap space. The proportion is always relative to the amount of "allowable" memory and not the total amount of RAM systemwide so that mempolicies and cpusets may operate in isolation; they shall not need to know the true size of the machine on which they are running if they are bound to a specific set of nodes or mems, respectively. Root tasks are given 3% extra memory just like __vm_enough_memory() provides in LSMs. In the event of two tasks consuming similar amounts of memory, it is generally better to save root's task. Because of the change in the badness() heuristic's baseline, it is also necessary to introduce a new user interface to tune it. It's not possible to redefine the meaning of /proc/pid/oom_adj with a new scale since the ABI cannot be changed for backward compatability. Instead, a new tunable, /proc/pid/oom_score_adj, is added that ranges from -1000 to +1000. It may be used to polarize the heuristic such that certain tasks are never considered for oom kill while others may always be considered. The value is added directly into the badness() score so a value of -500, for example, means to discount 50% of its memory consumption in comparison to other tasks either on the system, bound to the mempolicy, in the cpuset, or sharing the same memory controller. /proc/pid/oom_adj is changed so that its meaning is rescaled into the units used by /proc/pid/oom_score_adj, and vice versa. Changing one of these per-task tunables will rescale the value of the other to an equivalent meaning. Although /proc/pid/oom_adj was originally defined as a bitshift on the badness score, it now shares the same linear growth as /proc/pid/oom_score_adj but with different granularity. This is required so the ABI is not broken with userspace applications and allows oom_adj to be deprecated for future removal. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Nick Piggin <npiggin@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: kill prev_priority completelyKOSAKI Motohiro2010-08-101-31/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since 2.6.28 zone->prev_priority is unused. Then it can be removed safely. It reduce stack usage slightly. Now I have to say that I'm sorry. 2 years ago, I thought prev_priority can be integrate again, it's useful. but four (or more) times trying haven't got good performance number. Thus I give up such approach. The rest of this changelog is notes on prev_priority and why it existed in the first place and why it might be not necessary any more. This information is based heavily on discussions between Andrew Morton, Rik van Riel and Kosaki Motohiro who is heavily quotes from. Historically prev_priority was important because it determined when the VM would start unmapping PTE pages. i.e. there are no balances of note within the VM, Anon vs File and Mapped vs Unmapped. Without prev_priority, there is a potential risk of unnecessarily increasing minor faults as a large amount of read activity of use-once pages could push mapped pages to the end of the LRU and get unmapped. There is no proof this is still a problem but currently it is not considered to be. Active files are not deactivated if the active file list is smaller than the inactive list reducing the liklihood that file-mapped pages are being pushed off the LRU and referenced executable pages are kept on the active list to avoid them getting pushed out by read activity. Even if it is a problem, prev_priority prev_priority wouldn't works nowadays. First of all, current vmscan still a lot of UP centric code. it expose some weakness on some dozens CPUs machine. I think we need more and more improvement. The problem is, current vmscan mix up per-system-pressure, per-zone-pressure and per-task-pressure a bit. example, prev_priority try to boost priority to other concurrent priority. but if the another task have mempolicy restriction, it is unnecessary, but also makes wrong big latency and exceeding reclaim. per-task based priority + prev_priority adjustment make the emulation of per-system pressure. but it have two issue 1) too rough and brutal emulation 2) we need per-zone pressure, not per-system. Another example, currently DEF_PRIORITY is 12. it mean the lru rotate about 2 cycle (1/4096 + 1/2048 + 1/1024 + .. + 1) before invoking OOM-Killer. but if 10,0000 thrreads enter DEF_PRIORITY reclaim at the same time, the system have higher memory pressure than priority==0 (1/4096*10,000 > 2). prev_priority can't solve such multithreads workload issue. In other word, prev_priority concept assume the sysmtem don't have lots threads." Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Michael Rubin <mrubin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix wake up in oom wait queueKAMEZAWA Hiroyuki2010-06-301-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | OOM-waitqueue should be waken up when oom_disable is canceled. This is a fix for 3c11ecf448eff8f1 ("memcg: oom kill disable and oom status"). How to test: Create a cgroup A... 1. set memory.limit and memory.memsw.limit to be small value 2. echo 1 > /cgroup/A/memory.oom_control, this disables oom-kill. 3. run a program which must cause OOM. A program executed in 3 will sleep by oom_waiqueue in memcg. Then, how to wake it up is problem. 1. echo 0 > /cgroup/A/memory.oom_control (enable OOM-killer) 2. echo big mem > /cgroup/A/memory.memsw.limit_in_bytes(allow more swap) etc.. Without the patch, a task in slept can not be waken up. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: clean up memory thresholdsKirill A. Shutemov2010-05-271-85/+66
| | | | | | | | | | | | | | | | Introduce struct mem_cgroup_thresholds. It helps to reduce number of checks of thresholds type (memory or mem+swap). [akpm@linux-foundation.org: repair comment] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: make cftype.unregister_event() void-returningKirill A. Shutemov2010-05-271-24/+41
| | | | | | | | | | | | | | | | | | | | | Since we are unable to handle an error returned by cftype.unregister_event() properly, let's make the callback void-returning. mem_cgroup_unregister_event() has been rewritten to be a "never fail" function. On mem_cgroup_usage_register_event() we save old buffer for thresholds array and reuse it in mem_cgroup_usage_unregister_event() to avoid allocation. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix mis-accounting of file mapped racy with migrationakpm@linux-foundation.org2010-05-271-38/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | FILE_MAPPED per memcg of migrated file cache is not properly updated, because our hook in page_add_file_rmap() can't know to which memcg FILE_MAPPED should be counted. Basically, this patch is for fixing the bug but includes some big changes to fix up other messes. Now, at migrating mapped file, events happen in following sequence. 1. allocate a new page. 2. get memcg of an old page. 3. charge ageinst a new page before migration. But at this point, no changes to new page's page_cgroup, no commit for the charge. (IOW, PCG_USED bit is not set.) 4. page migration replaces radix-tree, old-page and new-page. 5. page migration remaps the new page if the old page was mapped. 6. Here, the new page is unlocked. 7. memcg commits the charge for newpage, Mark the new page's page_cgroup as PCG_USED. Because "commit" happens after page-remap, we can count FILE_MAPPED at "5", because we should avoid to trust page_cgroup->mem_cgroup. if PCG_USED bit is unset. (Note: memcg's LRU removal code does that but LRU-isolation logic is used for helping it. When we overwrite page_cgroup->mem_cgroup, page_cgroup is not on LRU or page_cgroup->mem_cgroup is NULL.) We can lose file_mapped accounting information at 5 because FILE_MAPPED is updated only when mapcount changes 0->1. So we should catch it. BTW, historically, above implemntation comes from migration-failure of anonymous page. Because we charge both of old page and new page with mapcount=0, we can't catch - the page is really freed before remap. - migration fails but it's freed before remap or .....corner cases. New migration sequence with memcg is: 1. allocate a new page. 2. mark PageCgroupMigration to the old page. 3. charge against a new page onto the old page's memcg. (here, new page's pc is marked as PageCgroupUsed.) 4. page migration replaces radix-tree, page table, etc... 5. At remapping, new page's page_cgroup is now makrked as "USED" We can catch 0->1 event and FILE_MAPPED will be properly updated. And we can catch SWAPOUT event after unlock this and freeing this page by unmap() can be caught. 7. Clear PageCgroupMigration of the old page. So, FILE_MAPPED will be correctly updated. Then, for what MIGRATION flag is ? Without it, at migration failure, we may have to charge old page again because it may be fully unmapped. "charge" means that we have to dive into memory reclaim or something complated. So, it's better to avoid charge it again. Before this patch, __commit_charge() was working for both of the old/new page and fixed up all. But this technique has some racy condtion around FILE_MAPPED and SWAPOUT etc... Now, the kernel use MIGRATION flag and don't uncharge old page until the end of migration. I hope this change will make memcg's page migration much simpler. This page migration has caused several troubles. Worth to add a flag for simplification. Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: memcontrol - uninitialised return valuePhil Carmody2010-05-271-1/+1
| | | | | | | | | | | | Only an out of memory error will cause ret to be set. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove unnecessary use of atomicPhil Carmody2010-05-271-7/+7
| | | | | | | | | | | | | | | | | | | | | | The bottom 4 hunks are atomically changing memory to which there are no aliases as it's freshly allocated, so there's no need to use atomic operations. The other hunks are just atomic_read and atomic_set, and do not involve any read-modify-write. The use of atomic_{read,set} doesn't prevent a read/write or write/write race, so if a race were possible (I'm not saying one is), then it would still be there even with atomic_set. See: http://digitalvampire.org/blog/index.php/2007/05/13/atomic-cargo-cults/ Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: move charge of file pagesDaisuke Nishimura2010-05-271-12/+44
| | | | | | | | | | | | | | | | | | | | | | This patch adds support for moving charge of file pages, which include normal file, tmpfs file and swaps of tmpfs file. It's enabled by setting bit 1 of <target cgroup>/memory.move_charge_at_immigrate. Unlike the case of anonymous pages, file pages(and swaps) in the range mmapped by the task will be moved even if the task hasn't done page fault, i.e. they might not be the task's "RSS", but other task's "RSS" that maps the same file. And mapcount of the page is ignored(the page can be moved even if page_mapcount(page) > 1). So, conditions that the page/swap should be met to be moved is that it must be in the range mmapped by the target task and it must be charged to the old cgroup. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix warning] Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: clean up move chargeDaisuke Nishimura2010-05-271-37/+59
| | | | | | | | | | | | | | | | This patch cleans up move charge code by: - define functions to handle pte for each types, and make is_target_pte_for_mc() cleaner. - instead of checking the MOVE_CHARGE_TYPE_ANON bit, define a function that checks the bit. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: oom kill disable and oom statusKAMEZAWA Hiroyuki2010-05-271-19/+94
| | | | | | | | | | | | | | | | | | | | | | | | | | | This adds a feature to disable oom-killer for memcg, if disabled, of course, tasks under memcg will stop. But now, we have oom-notifier for memcg. And the world around memcg is not under out-of-memory. memcg's out-of-memory just shows memcg hits limit. Then, administrator or management daemon can recover the situation by - kill some process - enlarge limit, add more swap. - migrate some tasks - remove file cache on tmps (difficult ?) Unlike oom-killer, you can take enough information before killing tasks. (by gcore, or, ps etc.) [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: oom notifierKAMEZAWA Hiroyuki2010-05-271-8/+92
| | | | | | | | | | | | | | | | | | | | | | | Considering containers or other resource management softwares in userland, event notification of OOM in memcg should be implemented. Now, memcg has "threshold" notifier which uses eventfd, we can make use of it for oom notification. This patch adds oom notification eventfd callback for memcg. The usage is very similar to threshold notifier, but control file is memory.oom_control and no arguments other than eventfd is required. % cgroup_event_notifier /cgroup/A/memory.oom_control dummy (About cgroup_event_notifier, see Documentation/cgroup/) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: oom wakeup filterKAMEZAWA Hiroyuki2010-05-271-17/+46
| | | | | | | | | | | | | | | | | memcg's oom waitqueue is a system-wide wait_queue (for handling hierarchy.) So, it's better to add custom wake function and do filtering in wake up path. This patch adds a filtering feature for waking up oom-waiters. Hierarchy is properly handled. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-05-201-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (44 commits) vlynq: make whole Kconfig-menu dependant on architecture add descriptive comment for TIF_MEMDIE task flag declaration. EEPROM: max6875: Header file cleanup EEPROM: 93cx6: Header file cleanup EEPROM: Header file cleanup agp: use NULL instead of 0 when pointer is needed rtc-v3020: make bitfield unsigned PCI: make bitfield unsigned jbd2: use NULL instead of 0 when pointer is needed cciss: fix shadows sparse warning doc: inode uses a mutex instead of a semaphore. uml: i386: Avoid redefinition of NR_syscalls fix "seperate" typos in comments cocbalt_lcdfb: correct sections doc: Change urls for sparse Powerpc: wii: Fix typo in comment i2o: cleanup some exit paths Documentation/: it's -> its where appropriate UML: Fix compiler warning due to missing task_struct declaration UML: add kernel.h include to signal.c ...
| * Merge branch 'master' into for-nextJiri Kosina2010-04-231-33/+35
| |\
| * | mm: fix typo in refill_stock() commentGreg Thelen2010-03-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | Change refill_stock() comment: s/consumt_stock()/consume_stock()/ Signed-off-by: Greg Thelen <gthelen@google.com> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | | memcg: fix css_is_ancestor() RCU lockingKAMEZAWA Hiroyuki2010-05-121-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some callers (in memcontrol.c) calls css_is_ancestor() without rcu_read_lock. Because css_is_ancestor() has to access RCU protected data, it should be under rcu_read_lock(). This makes css_is_ancestor() itself does safe access to RCU protected area. (At least, "root" can have refcnt==0 if it's not an ancestor of "child". So, we need rcu_read_lock().) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: 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>
* | | memcg: fix css_id() RCU locking for realKAMEZAWA Hiroyuki2010-05-121-14/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit ad4ba375373937817404fd92239ef4cadbded23b ("memcg: css_id() must be called under rcu_read_lock()") modifies memcontol.c for fixing RCU check message. But Andrew Morton pointed out that the fix doesn't seems sane and it was just for hidining lockdep messages. This is a patch for do proper things. Checking again, all places, accessing without rcu_read_lock, that commit fixies was intentional.... all callers of css_id() has reference count on it. So, it's not necessary to be under rcu_read_lock(). Considering again, we can use rcu_dereference_check for css_id(). We know css->id is valid if css->refcnt > 0. (css->id never changes and freed after css->refcnt going to be 0.) This patch makes use of rcu_dereference_check() in css_id/depth and remove unnecessary rcu-read-lock added by the commit. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: 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>
* | | Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds2010-05-071-5/+16
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: rcu: create rcu_my_thread_group_empty() wrapper memcg: css_id() must be called under rcu_read_lock() cgroup: Check task_lock in task_subsys_state() sched: Fix an RCU warning in print_task() cgroup: Fix an RCU warning in alloc_css_id() cgroup: Fix an RCU warning in cgroup_path() KEYS: Fix an RCU warning in the reading of user keys KEYS: Fix an RCU warning
| * | | memcg: css_id() must be called under rcu_read_lock()Paul E. McKenney2010-05-041-5/+16
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes task_in_mem_cgroup(), mem_cgroup_uncharge_swapcache(), mem_cgroup_move_swap_account(), and is_target_pte_for_mc() to protect calls to css_id(). An additional RCU lockdep splat was reported for memcg_oom_wake_function(), however, this function is not yet in mainline as of 2.6.34-rc5. Reported-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org>
* / | memcg: fix prepare migrationAndrea Arcangeli2010-04-241-2/+2
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If a signal is pending (task being killed by sigkill) __mem_cgroup_try_charge will write NULL into &mem, and css_put will oops on null pointer dereference. BUG: unable to handle kernel NULL pointer dereference at 0000000000000010 IP: [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0 PGD a5d89067 PUD a5d8a067 PMD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/platform/microcode/firmware/microcode/loading CPU 0 Modules linked in: nfs lockd nfs_acl auth_rpcgss sunrpc acpi_cpufreq pcspkr sg [last unloaded: microcode] Pid: 5299, comm: largepages Tainted: G W 2.6.34-rc3 #3 Penryn1600SLI-110dB/To Be Filled By O.E.M. RIP: 0010:[<ffffffff810fc6cc>] [<ffffffff810fc6cc>] mem_cgroup_prepare_migration+0x7c/0xc0 [nishimura@mxp.nes.nec.co.jp: fix merge issues] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | memcg: fix race in file_mapped accountingKAMEZAWA Hiroyuki2010-04-071-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Presently, memcg's FILE_MAPPED accounting has following race with move_account (happens at rmdir()). increment page->mapcount (rmap.c) mem_cgroup_update_file_mapped() move_account() lock_page_cgroup() check page_mapped() if page_mapped(page)>1 { FILE_MAPPED -1 from old memcg FILE_MAPPED +1 to old memcg } ..... overwrite pc->mem_cgroup unlock_page_cgroup() lock_page_cgroup() FILE_MAPPED + 1 to pc->mem_cgroup unlock_page_cgroup() Then, old memcg (-1 file mapped) new memcg (+2 file mapped) This happens because move_account see page_mapped() which is not guarded by lock_page_cgroup(). This patch adds FILE_MAPPED flag to page_cgroup and move account information based on it. Now, all checks are synchronous with lock_page_cgroup(). Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Balbir Singh <balbir@in.ibm.com> Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Andrea Righi <arighi@develer.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | memcontrol: fix potential null derefDan Carpenter2010-03-251-2/+4
| | | | | | | | | | | | | | | | | | | | There was a potential null deref introduced in c62b1a3b31b5 ("memcg: use generic percpu instead of private implementation"). Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | memcg: disable move charge in no mmu caseDaisuke Nishimura2010-03-251-22/+22
|/ | | | | | | | | | | | | | | | In commit 02491447 ("memcg: move charges of anonymous swap"), I tried to disable move charge feature in no mmu case by enclosing all the related functions with "#ifdef CONFIG_MMU", but the commit places these ifdefs in wrong place. (it seems that it's mangled while handling some fixes...) This patch fixes it up. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: fix oom kill behaviorKAMEZAWA Hiroyuki2010-03-131-27/+107
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In current page-fault code, handle_mm_fault() -> ... -> mem_cgroup_charge() -> map page or handle error. -> check return code. If page fault's return code is VM_FAULT_OOM, page_fault_out_of_memory() is called. But if it's caused by memcg, OOM should have been already invoked. Then, I added a patch: a636b327f731143ccc544b966cfd8de6cb6d72c6. That patch records last_oom_jiffies for memcg's sub-hierarchy and prevents page_fault_out_of_memory from being invoked in near future. But Nishimura-san reported that check by jiffies is not enough when the system is terribly heavy. This patch changes memcg's oom logic as. * If memcg causes OOM-kill, continue to retry. * remove jiffies check which is used now. * add memcg-oom-lock which works like perzone oom lock. * If current is killed(as a process), bypass charge. Something more sophisticated can be added but this pactch does fundamental things. TODO: - add oom notifier - add permemcg disable-oom-kill flag and freezer at oom. - more chances for wake up oom waiter (when changing memory limit etc..) Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cgroups: remove events before destroying subsystem state objectsKirill A. Shutemov2010-03-131-9/+0
| | | | | | | | | | | | | | | | | Events should be removed after rmdir of cgroup directory, but before destroying subsystem state objects. Let's take reference to cgroup directory dentry to do that. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg : share event counter rather than duplicateKAMEZAWA Hiroyuki2010-03-131-45/+41
| | | | | | | | | | | | | | | | | | | Memcg has 2 eventcountes which counts "the same" event. Just usages are different from each other. This patch tries to reduce event counter. Now logic uses "only increment, no reset" counter and masks for each checks. Softlimit chesk was done per 1000 evetns. So, the similar check can be done by !(new_counter & 0x3ff). Threshold check was done per 100 events. So, the similar check can be done by (!new_counter & 0x7f) ALL event checks are done right after EVENT percpu counter is updated. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: update threshold and softlimit at commitKAMEZAWA Hiroyuki2010-03-131-20/+18
| | | | | | | | | | | | | | | | | | | | | Presently, move_task does "batched" precharge. Because res_counter or css's refcnt are not-scalable jobs for memcg, try_charge_().. tend to be done in batched manner if allowed. Now, softlimit and threshold check their event counter in try_charge, but the charge is not a per-page event. And event counter is not updated at charge(). Moreover, precharge doesn't pass "page" to try_charge() and softlimit tree will be never updated until uncharge() causes an event." So the best place to check the event counter is commit_charge(). This is per-page event by its nature. This patch move checks to there. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: use generic percpu instead of private implementationKAMEZAWA Hiroyuki2010-03-131-121/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When per-cpu counter for memcg was implemneted, dynamic percpu allocator was not very good. But now, we have good one and useful macros. This patch replaces memcg's private percpu counter implementation with generic dynamic percpu allocator. The benefits are - We can remove private implementation. - The counters will be NUMA-aware. (Current one is not...) - This patch makes sizeof struct mem_cgroup smaller. Then, struct mem_cgroup may be fit in page size on small config. - About basic performance aspects, see below. [Before] # size mm/memcontrol.o text data bss dec hex filename 24373 2528 4132 31033 7939 mm/memcontrol.o [page-fault-throuput test on 8cpu/SMP in root cgroup] # /root/bin/perf stat -a -e page-faults,cache-misses --repeat 5 ./multi-fault-fork 8 Performance counter stats for './multi-fault-fork 8' (5 runs): 45878618 page-faults ( +- 0.110% ) 602635826 cache-misses ( +- 0.105% ) 61.005373262 seconds time elapsed ( +- 0.004% ) Then cache-miss/page fault = 13.14 [After] #size mm/memcontrol.o text data bss dec hex filename 23913 2528 4132 30573 776d mm/memcontrol.o # /root/bin/perf stat -a -e page-faults,cache-misses --repeat 5 ./multi-fault-fork 8 Performance counter stats for './multi-fault-fork 8' (5 runs): 48179400 page-faults ( +- 0.271% ) 588628407 cache-misses ( +- 0.136% ) 61.004615021 seconds time elapsed ( +- 0.004% ) Then cache-miss/page fault = 12.22 Text size is reduced. This performance improvement is not big and will be invisible in real world applications. But this result shows this patch has some good effect even on (small) SMP. Here is a test program I used. 1. fork() processes on each cpus. 2. do page fault repeatedly on each process. 3. after 60secs, kill all childredn and exit. (3 is necessary for getting stable data, this is improvement from previous one.) #define _GNU_SOURCE #include <stdio.h> #include <sched.h> #include <sys/mman.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <signal.h> #include <stdlib.h> /* * For avoiding contention in page table lock, FAULT area is * sparse. If FAULT_LENGTH is too large for your cpus, decrease it. */ #define FAULT_LENGTH (2 * 1024 * 1024) #define PAGE_SIZE 4096 #define MAXNUM (128) void alarm_handler(int sig) { } void *worker(int cpu, int ppid) { void *start, *end; char *c; cpu_set_t set; int i; CPU_ZERO(&set); CPU_SET(cpu, &set); sched_setaffinity(0, sizeof(set), &set); start = mmap(NULL, FAULT_LENGTH, PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); if (start == MAP_FAILED) { perror("mmap"); exit(1); } end = start + FAULT_LENGTH; pause(); //fprintf(stderr, "run%d", cpu); while (1) { for (c = (char*)start; (void *)c < end; c += PAGE_SIZE) *c = 0; madvise(start, FAULT_LENGTH, MADV_DONTNEED); } return NULL; } int main(int argc, char *argv[]) { int num, i, ret, pid, status; int pids[MAXNUM]; if (argc < 2) return 0; setpgid(0, 0); signal(SIGALRM, alarm_handler); num = atoi(argv[1]); pid = getpid(); for (i = 0; i < num; ++i) { ret = fork(); if (!ret) { worker(i, pid); exit(0); } pids[i] = ret; } sleep(1); kill(-pid, SIGALRM); sleep(60); for (i = 0; i < num; i++) kill(pids[i], SIGKILL); for (i = 0; i < num; i++) waitpid(pids[i], &status, 0); return 0; } Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: typo in comment to mem_cgroup_print_oom_info()Kirill A. Shutemov2010-03-131-1/+1
| | | | | | | | | | | s/mem_cgroup_print_mem_info/mem_cgroup_print_oom_info/ Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: implement memory thresholdsKirill A. Shutemov2010-03-131-0/+309
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It allows to register multiple memory and memsw thresholds and gets notifications when it crosses. To register a threshold application need: - create an eventfd; - open memory.usage_in_bytes or memory.memsw.usage_in_bytes; - write string like "<event_fd> <memory.usage_in_bytes> <threshold>" to cgroup.event_control. Application will be notified through eventfd when memory usage crosses threshold in any direction. It's applicable for root and non-root cgroup. It uses stats to track memory usage, simmilar to soft limits. It checks if we need to send event to userspace on every 100 page in/out. I guess it's good compromise between performance and accuracy of thresholds. [akpm@linux-foundation.org: coding-style fixes] [nishimura@mxp.nes.nec.co.jp: fix documentation merge issue] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: rework usage of stats by soft limitKirill A. Shutemov2010-03-131-8/+10
| | | | | | | | | | | | | | | | | | | | | | | | | Instead of incrementing counter on each page in/out and comparing it with constant, we set counter to constant, decrement counter on each page in/out and compare it with zero. We want to make comparing as fast as possible. On many RISC systems (probably not only RISC) comparing with zero is more effective than comparing with a constant, since not every constant can be immediate operand for compare instruction. Also, I've renamed MEM_CGROUP_STAT_EVENTS to MEM_CGROUP_STAT_SOFTLIMIT, since really it's not a generic counter. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: extract mem_group_usage() from mem_cgroup_read()Kirill A. Shutemov2010-03-131-22/+32
| | | | | | | | | | | | | | | | | Helper to get memory or mem+swap usage of the cgroup. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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