memcg: oom kill disable and oom status
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>
This commit is contained in:
KAMEZAWA Hiroyuki
Linus Torvalds
Родитель
9490ff2756
Коммит
3c11ecf448
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@ -493,6 +493,8 @@ It's applicable for root and non-root cgroup.
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10. OOM Control
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memory.oom_control file is for OOM notification and other controls.
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Memory controler implements oom notifier using cgroup notification
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API (See cgroups.txt). It allows to register multiple oom notification
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delivery and gets notification when oom happens.
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@ -505,6 +507,27 @@ To register a notifier, application need:
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Application will be notifier through eventfd when oom happens.
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OOM notification doesn't work for root cgroup.
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You can disable oom-killer by writing "1" to memory.oom_control file.
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As.
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#echo 1 > memory.oom_control
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This operation is only allowed to the top cgroup of subhierarchy.
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If oom-killer is disabled, tasks under cgroup will hang/sleep
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in memcg's oom-waitq when they request accountable memory.
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For running them, you have to relax the memcg's oom sitaution by
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* enlarge limit or reduce usage.
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To reduce usage,
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* kill some tasks.
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* move some tasks to other group with account migration.
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* remove some files (on tmpfs?)
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Then, stopped tasks will work again.
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At reading, current status of OOM is shown.
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oom_kill_disable 0 or 1 (if 1, oom-killer is disabled)
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under_oom 0 or 1 (if 1, the memcg is under OOM,tasks may
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be stopped.)
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11. TODO
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111
mm/memcontrol.c
111
mm/memcontrol.c
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@ -214,6 +214,8 @@ struct mem_cgroup {
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atomic_t refcnt;
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unsigned int swappiness;
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/* OOM-Killer disable */
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int oom_kill_disable;
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/* set when res.limit == memsw.limit */
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bool memsw_is_minimum;
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@ -235,7 +237,6 @@ struct mem_cgroup {
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* mem_cgroup ? And what type of charges should we move ?
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*/
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unsigned long move_charge_at_immigrate;
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/*
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* percpu counter.
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*/
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@ -1342,20 +1343,26 @@ static void memcg_wakeup_oom(struct mem_cgroup *mem)
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__wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem);
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}
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static void memcg_oom_recover(struct mem_cgroup *mem)
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{
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if (mem->oom_kill_disable && atomic_read(&mem->oom_lock))
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memcg_wakeup_oom(mem);
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}
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/*
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* try to call OOM killer. returns false if we should exit memory-reclaim loop.
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*/
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bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
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{
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struct oom_wait_info owait;
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bool locked;
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bool locked, need_to_kill;
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owait.mem = mem;
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owait.wait.flags = 0;
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owait.wait.func = memcg_oom_wake_function;
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owait.wait.private = current;
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INIT_LIST_HEAD(&owait.wait.task_list);
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need_to_kill = true;
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/* At first, try to OOM lock hierarchy under mem.*/
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mutex_lock(&memcg_oom_mutex);
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locked = mem_cgroup_oom_lock(mem);
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@ -1364,15 +1371,17 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
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* accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
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* under OOM is always welcomed, use TASK_KILLABLE here.
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*/
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if (!locked)
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prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
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else
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if (!locked || mem->oom_kill_disable)
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need_to_kill = false;
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if (locked)
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mem_cgroup_oom_notify(mem);
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mutex_unlock(&memcg_oom_mutex);
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if (locked)
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if (need_to_kill) {
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finish_wait(&memcg_oom_waitq, &owait.wait);
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mem_cgroup_out_of_memory(mem, mask);
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else {
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} else {
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schedule();
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finish_wait(&memcg_oom_waitq, &owait.wait);
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}
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@ -2162,15 +2171,6 @@ __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
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/* If swapout, usage of swap doesn't decrease */
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if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
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uncharge_memsw = false;
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/*
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* do_batch > 0 when unmapping pages or inode invalidate/truncate.
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* In those cases, all pages freed continously can be expected to be in
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* the same cgroup and we have chance to coalesce uncharges.
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* But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
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* because we want to do uncharge as soon as possible.
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*/
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if (!current->memcg_batch.do_batch || test_thread_flag(TIF_MEMDIE))
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goto direct_uncharge;
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batch = ¤t->memcg_batch;
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/*
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@ -2180,6 +2180,17 @@ __do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype)
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*/
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if (!batch->memcg)
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batch->memcg = mem;
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/*
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* do_batch > 0 when unmapping pages or inode invalidate/truncate.
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* In those cases, all pages freed continously can be expected to be in
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* the same cgroup and we have chance to coalesce uncharges.
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* But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
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* because we want to do uncharge as soon as possible.
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*/
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if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
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goto direct_uncharge;
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/*
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* In typical case, batch->memcg == mem. This means we can
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* merge a series of uncharges to an uncharge of res_counter.
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@ -2196,6 +2207,8 @@ direct_uncharge:
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res_counter_uncharge(&mem->res, PAGE_SIZE);
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if (uncharge_memsw)
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res_counter_uncharge(&mem->memsw, PAGE_SIZE);
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if (unlikely(batch->memcg != mem))
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memcg_oom_recover(mem);
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return;
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}
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@ -2332,6 +2345,7 @@ void mem_cgroup_uncharge_end(void)
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res_counter_uncharge(&batch->memcg->res, batch->bytes);
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if (batch->memsw_bytes)
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res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes);
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memcg_oom_recover(batch->memcg);
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/* forget this pointer (for sanity check) */
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batch->memcg = NULL;
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}
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@ -2568,10 +2582,11 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
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unsigned long long val)
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{
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int retry_count;
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u64 memswlimit;
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u64 memswlimit, memlimit;
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int ret = 0;
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int children = mem_cgroup_count_children(memcg);
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u64 curusage, oldusage;
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int enlarge;
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/*
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* For keeping hierarchical_reclaim simple, how long we should retry
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@ -2582,6 +2597,7 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
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oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
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enlarge = 0;
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while (retry_count) {
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if (signal_pending(current)) {
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ret = -EINTR;
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@ -2599,6 +2615,11 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
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mutex_unlock(&set_limit_mutex);
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break;
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}
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memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
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if (memlimit < val)
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enlarge = 1;
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ret = res_counter_set_limit(&memcg->res, val);
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if (!ret) {
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if (memswlimit == val)
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@ -2620,6 +2641,8 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
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else
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oldusage = curusage;
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}
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if (!ret && enlarge)
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memcg_oom_recover(memcg);
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return ret;
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}
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@ -2628,9 +2651,10 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
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unsigned long long val)
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{
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int retry_count;
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u64 memlimit, oldusage, curusage;
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u64 memlimit, memswlimit, oldusage, curusage;
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int children = mem_cgroup_count_children(memcg);
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int ret = -EBUSY;
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int enlarge = 0;
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/* see mem_cgroup_resize_res_limit */
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retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
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@ -2652,6 +2676,9 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
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mutex_unlock(&set_limit_mutex);
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break;
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}
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memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
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if (memswlimit < val)
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enlarge = 1;
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ret = res_counter_set_limit(&memcg->memsw, val);
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if (!ret) {
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if (memlimit == val)
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@ -2674,6 +2701,8 @@ static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
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else
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oldusage = curusage;
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}
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if (!ret && enlarge)
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memcg_oom_recover(memcg);
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return ret;
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}
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@ -2865,6 +2894,7 @@ move_account:
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if (ret)
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break;
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}
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memcg_oom_recover(mem);
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/* it seems parent cgroup doesn't have enough mem */
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if (ret == -ENOMEM)
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goto try_to_free;
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@ -3645,6 +3675,46 @@ static int mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
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return 0;
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}
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static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
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struct cftype *cft, struct cgroup_map_cb *cb)
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{
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struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
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cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable);
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if (atomic_read(&mem->oom_lock))
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cb->fill(cb, "under_oom", 1);
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else
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cb->fill(cb, "under_oom", 0);
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return 0;
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}
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/*
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*/
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static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
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struct cftype *cft, u64 val)
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{
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struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
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struct mem_cgroup *parent;
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/* cannot set to root cgroup and only 0 and 1 are allowed */
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if (!cgrp->parent || !((val == 0) || (val == 1)))
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return -EINVAL;
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parent = mem_cgroup_from_cont(cgrp->parent);
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cgroup_lock();
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/* oom-kill-disable is a flag for subhierarchy. */
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if ((parent->use_hierarchy) ||
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(mem->use_hierarchy && !list_empty(&cgrp->children))) {
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cgroup_unlock();
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return -EINVAL;
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}
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mem->oom_kill_disable = val;
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cgroup_unlock();
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return 0;
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}
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static struct cftype mem_cgroup_files[] = {
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{
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.name = "usage_in_bytes",
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@ -3702,6 +3772,8 @@ static struct cftype mem_cgroup_files[] = {
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},
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{
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.name = "oom_control",
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.read_map = mem_cgroup_oom_control_read,
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.write_u64 = mem_cgroup_oom_control_write,
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.register_event = mem_cgroup_oom_register_event,
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.unregister_event = mem_cgroup_oom_unregister_event,
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.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
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@ -3943,6 +4015,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
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} else {
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parent = mem_cgroup_from_cont(cont->parent);
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mem->use_hierarchy = parent->use_hierarchy;
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mem->oom_kill_disable = parent->oom_kill_disable;
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}
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if (parent && parent->use_hierarchy) {
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@ -4215,6 +4288,7 @@ static void mem_cgroup_clear_mc(void)
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if (mc.precharge) {
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__mem_cgroup_cancel_charge(mc.to, mc.precharge);
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mc.precharge = 0;
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memcg_oom_recover(mc.to);
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}
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/*
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* we didn't uncharge from mc.from at mem_cgroup_move_account(), so
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@ -4223,6 +4297,7 @@ static void mem_cgroup_clear_mc(void)
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if (mc.moved_charge) {
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__mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
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mc.moved_charge = 0;
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memcg_oom_recover(mc.from);
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}
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/* we must fixup refcnts and charges */
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if (mc.moved_swap) {
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