From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754086Ab0KWXvc (ORCPT ); Tue, 23 Nov 2010 18:51:32 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:49247 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753016Ab0KWXvb (ORCPT ); Tue, 23 Nov 2010 18:51:31 -0500 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Linus Torvalds Subject: Re: [PATCH] Revert oom rewrite series Cc: kosaki.motohiro@jp.fujitsu.com, LKML , David Rientjes , Andrew Morton , Ying Han , Bodo Eggert <7eggert@web.de>, Mandeep Singh Baines , "Figo.zhang" In-Reply-To: References: <20101114133543.E00A.A69D9226@jp.fujitsu.com> Message-Id: <20101124085102.7BE2.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Wed, 24 Nov 2010 08:51:26 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > 2010/11/13 KOSAKI Motohiro : > > > > Please apply this. this patch revert commits of oom changes since v2.6.35. > > I'm not getting involved in this whole flame-war. You need to convince > Andrew, who has been the person everything went through. I did. Therefore, I will resend the patch to you. Thanks. -------------------------------------------------------------------------- Subject: [PATCH] Revert oom rewrite series This reverts following commits. They has broke an ABI and made multiple enduser claim. 9c28ab662a8e3d19d07077ac0a8931c015e8afec Revert "oom: badness heuristic rewrite" 74cd8c6cb3e093c4d67ac3eb3581e246e4981dad Revert "oom: deprecate oom_adj tunable" 79a0bd5796e754c4b4e22071c4edddef3517d010 Revert "memcg: use find_lock_task_mm() in memory cgroups oom" a465ef80c2a9fe73c85029fcea5c68ffee8dbb69 Revert "oom: always return a badness score of non-zero for eligible tas 516fcbb0c45d943df1b739d3be3d417aee2275f3 Revert "oom: filter unkillable tasks from tasklist dump" b1c98f95a7954c450dadd809280f86863ea9d05d Revert "oom: add per-mm oom disable count" fd79f3f47c82a0af5288afe7556905dd171bfc43 Revert "oom: avoid killing a task if a thread sharing its mm cannot be 2d72175528870dcef577db4a2a0b49d819c6eaff Revert "oom: kill all threads sharing oom killed task's mm" be212960618ddcdb9526ce2cb73fd081fd3e90ea Revert "oom: rewrite error handling for oom_adj and oom_score_adj tunab 1b17c41599c594c7d11ef415a92d47c205fe89ea Revert "oom: fix locking for oom_adj and oom_score_adj" Signed-off-by: KOSAKI Motohiro --- Documentation/feature-removal-schedule.txt | 25 --- Documentation/filesystems/proc.txt | 97 ++++----- fs/exec.c | 5 - fs/proc/base.c | 176 ++-------------- include/linux/memcontrol.h | 8 - include/linux/mm_types.h | 2 - include/linux/oom.h | 19 +-- include/linux/sched.h | 3 +- kernel/exit.c | 3 - kernel/fork.c | 16 +-- mm/memcontrol.c | 28 +--- mm/oom_kill.c | 323 ++++++++++++++-------------- 12 files changed, 227 insertions(+), 478 deletions(-) diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index d8f36f9..9af16b9 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -166,31 +166,6 @@ Who: Eric Biederman --------------------------- -What: /proc//oom_adj -When: August 2012 -Why: /proc//oom_adj allows userspace to influence the oom killer's - badness heuristic used to determine which task to kill when the kernel - is out of memory. - - The badness heuristic has since been rewritten since the introduction of - this tunable such that its meaning is deprecated. The value was - implemented as a bitshift on a score generated by the badness() - function that did not have any precise units of measure. With the - rewrite, the score is given as a proportion of available memory to the - task allocating pages, so using a bitshift which grows the score - exponentially is, thus, impossible to tune with fine granularity. - - A much more powerful interface, /proc//oom_score_adj, was - introduced with the oom killer rewrite that allows users to increase or - decrease the badness() score linearly. This interface will replace - /proc//oom_adj. - - A warning will be emitted to the kernel log if an application uses this - deprecated interface. After it is printed once, future warnings will be - suppressed until the kernel is rebooted. - ---------------------------- - What: remove EXPORT_SYMBOL(kernel_thread) When: August 2006 Files: arch/*/kernel/*_ksyms.c diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index e73df27..030e3a1 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -33,8 +33,7 @@ Table of Contents 2 Modifying System Parameters 3 Per-Process Parameters - 3.1 /proc//oom_adj & /proc//oom_score_adj - Adjust the oom-killer - score + 3.1 /proc//oom_adj - Adjust the oom-killer score 3.2 /proc//oom_score - Display current oom-killer score 3.3 /proc//io - Display the IO accounting fields 3.4 /proc//coredump_filter - Core dump filtering settings @@ -1246,64 +1245,42 @@ of the kernel. CHAPTER 3: PER-PROCESS PARAMETERS ------------------------------------------------------------------------------ -3.1 /proc//oom_adj & /proc//oom_score_adj- Adjust the oom-killer score --------------------------------------------------------------------------------- - -These file can be used to adjust the badness heuristic used to select which -process gets killed in out of memory conditions. - -The badness heuristic assigns a value to each candidate task ranging from 0 -(never kill) to 1000 (always kill) to determine which process is targeted. The -units are roughly a proportion along that range of allowed memory the process -may allocate from based on an estimation of its current memory and swap use. -For example, if a task is using all allowed memory, its badness score will be -1000. If it is using half of its allowed memory, its score will be 500. - -There is an additional factor included in the badness score: root -processes are given 3% extra memory over other tasks. - -The amount of "allowed" memory depends on the context in which the oom killer -was called. If it is due to the memory assigned to the allocating task's cpuset -being exhausted, the allowed memory represents the set of mems assigned to that -cpuset. If it is due to a mempolicy's node(s) being exhausted, the allowed -memory represents the set of mempolicy nodes. If it is due to a memory -limit (or swap limit) being reached, the allowed memory is that configured -limit. Finally, if it is due to the entire system being out of memory, the -allowed memory represents all allocatable resources. - -The value of /proc//oom_score_adj is added to the badness score before it -is used to determine which task to kill. Acceptable values range from -1000 -(OOM_SCORE_ADJ_MIN) to +1000 (OOM_SCORE_ADJ_MAX). This allows userspace to -polarize the preference for oom killing either by always preferring a certain -task or completely disabling it. The lowest possible value, -1000, is -equivalent to disabling oom killing entirely for that task since it will always -report a badness score of 0. - -Consequently, it is very simple for userspace to define the amount of memory to -consider for each task. Setting a /proc//oom_score_adj value of +500, for -example, is roughly equivalent to allowing the remainder of tasks sharing the -same system, cpuset, mempolicy, or memory controller resources to use at least -50% more memory. A value of -500, on the other hand, would be roughly -equivalent to discounting 50% of the task's allowed memory from being considered -as scoring against the task. - -For backwards compatibility with previous kernels, /proc//oom_adj may also -be used to tune the badness score. Its acceptable values range from -16 -(OOM_ADJUST_MIN) to +15 (OOM_ADJUST_MAX) and a special value of -17 -(OOM_DISABLE) to disable oom killing entirely for that task. Its value is -scaled linearly with /proc//oom_score_adj. - -Writing to /proc//oom_score_adj or /proc//oom_adj will change the -other with its scaled value. - -NOTICE: /proc//oom_adj is deprecated and will be removed, please see -Documentation/feature-removal-schedule.txt. - -Caveat: when a parent task is selected, the oom killer will sacrifice any first -generation children with seperate address spaces instead, if possible. This -avoids servers and important system daemons from being killed and loses the -minimal amount of work. - +3.1 /proc//oom_adj - Adjust the oom-killer score +------------------------------------------------------ + +This file can be used to adjust the score used to select which processes +should be killed in an out-of-memory situation. Giving it a high score will +increase the likelihood of this process being killed by the oom-killer. Valid +values are in the range -16 to +15, plus the special value -17, which disables +oom-killing altogether for this process. + +The process to be killed in an out-of-memory situation is selected among all others +based on its badness score. This value equals the original memory size of the process +and is then updated according to its CPU time (utime + stime) and the +run time (uptime - start time). The longer it runs the smaller is the score. +Badness score is divided by the square root of the CPU time and then by +the double square root of the run time. + +Swapped out tasks are killed first. Half of each child's memory size is added to +the parent's score if they do not share the same memory. Thus forking servers +are the prime candidates to be killed. Having only one 'hungry' child will make +parent less preferable than the child. + +/proc//oom_score shows process' current badness score. + +The following heuristics are then applied: + * if the task was reniced, its score doubles + * superuser or direct hardware access tasks (CAP_SYS_ADMIN, CAP_SYS_RESOURCE + or CAP_SYS_RAWIO) have their score divided by 4 + * if oom condition happened in one cpuset and checked process does not belong + to it, its score is divided by 8 + * the resulting score is multiplied by two to the power of oom_adj, i.e. + points <<= oom_adj when it is positive and + points >>= -(oom_adj) otherwise + +The task with the highest badness score is then selected and its children +are killed, process itself will be killed in an OOM situation when it does +not have children or some of them disabled oom like described above. 3.2 /proc//oom_score - Display current oom-killer score ------------------------------------------------------------- diff --git a/fs/exec.c b/fs/exec.c index 99d33a1..47986fb 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -54,7 +54,6 @@ #include #include #include -#include #include #include @@ -766,10 +765,6 @@ static int exec_mmap(struct mm_struct *mm) tsk->mm = mm; tsk->active_mm = mm; activate_mm(active_mm, mm); - if (old_mm && tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { - atomic_dec(&old_mm->oom_disable_count); - atomic_inc(&tsk->mm->oom_disable_count); - } task_unlock(tsk); arch_pick_mmap_layout(mm); if (old_mm) { diff --git a/fs/proc/base.c b/fs/proc/base.c index f3d02ca..ed7d18e 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -63,7 +63,6 @@ #include #include #include -#include #include #include #include @@ -431,11 +430,12 @@ static const struct file_operations proc_lstats_operations = { static int proc_oom_score(struct task_struct *task, char *buffer) { unsigned long points = 0; + struct timespec uptime; + do_posix_clock_monotonic_gettime(&uptime); read_lock(&tasklist_lock); if (pid_alive(task)) - points = oom_badness(task, NULL, NULL, - totalram_pages + total_swap_pages); + points = badness(task, NULL, NULL, uptime.tv_sec); read_unlock(&tasklist_lock); return sprintf(buffer, "%lu\n", points); } @@ -1025,74 +1025,36 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf, memset(buffer, 0, sizeof(buffer)); if (count > sizeof(buffer) - 1) count = sizeof(buffer) - 1; - if (copy_from_user(buffer, buf, count)) { - err = -EFAULT; - goto out; - } + if (copy_from_user(buffer, buf, count)) + return -EFAULT; err = strict_strtol(strstrip(buffer), 0, &oom_adjust); if (err) - goto out; + return -EINVAL; if ((oom_adjust < OOM_ADJUST_MIN || oom_adjust > OOM_ADJUST_MAX) && - oom_adjust != OOM_DISABLE) { - err = -EINVAL; - goto out; - } + oom_adjust != OOM_DISABLE) + return -EINVAL; task = get_proc_task(file->f_path.dentry->d_inode); - if (!task) { - err = -ESRCH; - goto out; - } - - task_lock(task); - if (!task->mm) { - err = -EINVAL; - goto err_task_lock; - } - + if (!task) + return -ESRCH; if (!lock_task_sighand(task, &flags)) { - err = -ESRCH; - goto err_task_lock; + put_task_struct(task); + return -ESRCH; } if (oom_adjust < task->signal->oom_adj && !capable(CAP_SYS_RESOURCE)) { - err = -EACCES; - goto err_sighand; - } - - if (oom_adjust != task->signal->oom_adj) { - if (oom_adjust == OOM_DISABLE) - atomic_inc(&task->mm->oom_disable_count); - if (task->signal->oom_adj == OOM_DISABLE) - atomic_dec(&task->mm->oom_disable_count); + unlock_task_sighand(task, &flags); + put_task_struct(task); + return -EACCES; } - /* - * Warn that /proc/pid/oom_adj is deprecated, see - * Documentation/feature-removal-schedule.txt. - */ - printk_once(KERN_WARNING "%s (%d): /proc/%d/oom_adj is deprecated, " - "please use /proc/%d/oom_score_adj instead.\n", - current->comm, task_pid_nr(current), - task_pid_nr(task), task_pid_nr(task)); task->signal->oom_adj = oom_adjust; - /* - * Scale /proc/pid/oom_score_adj appropriately ensuring that a maximum - * value is always attainable. - */ - if (task->signal->oom_adj == OOM_ADJUST_MAX) - task->signal->oom_score_adj = OOM_SCORE_ADJ_MAX; - else - task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) / - -OOM_DISABLE; -err_sighand: + unlock_task_sighand(task, &flags); -err_task_lock: - task_unlock(task); put_task_struct(task); -out: - return err < 0 ? err : count; + + return count; } static const struct file_operations proc_oom_adjust_operations = { @@ -1101,106 +1063,6 @@ static const struct file_operations proc_oom_adjust_operations = { .llseek = generic_file_llseek, }; -static ssize_t oom_score_adj_read(struct file *file, char __user *buf, - size_t count, loff_t *ppos) -{ - struct task_struct *task = get_proc_task(file->f_path.dentry->d_inode); - char buffer[PROC_NUMBUF]; - int oom_score_adj = OOM_SCORE_ADJ_MIN; - unsigned long flags; - size_t len; - - if (!task) - return -ESRCH; - if (lock_task_sighand(task, &flags)) { - oom_score_adj = task->signal->oom_score_adj; - unlock_task_sighand(task, &flags); - } - put_task_struct(task); - len = snprintf(buffer, sizeof(buffer), "%d\n", oom_score_adj); - return simple_read_from_buffer(buf, count, ppos, buffer, len); -} - -static ssize_t oom_score_adj_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) -{ - struct task_struct *task; - char buffer[PROC_NUMBUF]; - unsigned long flags; - long oom_score_adj; - int err; - - memset(buffer, 0, sizeof(buffer)); - if (count > sizeof(buffer) - 1) - count = sizeof(buffer) - 1; - if (copy_from_user(buffer, buf, count)) { - err = -EFAULT; - goto out; - } - - err = strict_strtol(strstrip(buffer), 0, &oom_score_adj); - if (err) - goto out; - if (oom_score_adj < OOM_SCORE_ADJ_MIN || - oom_score_adj > OOM_SCORE_ADJ_MAX) { - err = -EINVAL; - goto out; - } - - task = get_proc_task(file->f_path.dentry->d_inode); - if (!task) { - err = -ESRCH; - goto out; - } - - task_lock(task); - if (!task->mm) { - err = -EINVAL; - goto err_task_lock; - } - - if (!lock_task_sighand(task, &flags)) { - err = -ESRCH; - goto err_task_lock; - } - - if (oom_score_adj < task->signal->oom_score_adj && - !capable(CAP_SYS_RESOURCE)) { - err = -EACCES; - goto err_sighand; - } - - if (oom_score_adj != task->signal->oom_score_adj) { - if (oom_score_adj == OOM_SCORE_ADJ_MIN) - atomic_inc(&task->mm->oom_disable_count); - if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) - atomic_dec(&task->mm->oom_disable_count); - } - task->signal->oom_score_adj = oom_score_adj; - /* - * Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is - * always attainable. - */ - if (task->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) - task->signal->oom_adj = OOM_DISABLE; - else - task->signal->oom_adj = (oom_score_adj * OOM_ADJUST_MAX) / - OOM_SCORE_ADJ_MAX; -err_sighand: - unlock_task_sighand(task, &flags); -err_task_lock: - task_unlock(task); - put_task_struct(task); -out: - return err < 0 ? err : count; -} - -static const struct file_operations proc_oom_score_adj_operations = { - .read = oom_score_adj_read, - .write = oom_score_adj_write, - .llseek = default_llseek, -}; - #ifdef CONFIG_AUDITSYSCALL #define TMPBUFLEN 21 static ssize_t proc_loginuid_read(struct file * file, char __user * buf, @@ -2779,7 +2641,6 @@ static const struct pid_entry tgid_base_stuff[] = { #endif INF("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adjust_operations), - REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations), #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), @@ -3115,7 +2976,6 @@ static const struct pid_entry tid_base_stuff[] = { #endif INF("oom_score", S_IRUGO, proc_oom_score), REG("oom_adj", S_IRUGO|S_IWUSR, proc_oom_adjust_operations), - REG("oom_score_adj", S_IRUGO|S_IWUSR, proc_oom_score_adj_operations), #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUSR, proc_sessionid_operations), diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 159a076..b13fc2a 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -124,8 +124,6 @@ static inline bool mem_cgroup_disabled(void) void mem_cgroup_update_file_mapped(struct page *page, int val); unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, gfp_t gfp_mask); -u64 mem_cgroup_get_limit(struct mem_cgroup *mem); - #else /* CONFIG_CGROUP_MEM_RES_CTLR */ struct mem_cgroup; @@ -305,12 +303,6 @@ unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, return 0; } -static inline -u64 mem_cgroup_get_limit(struct mem_cgroup *mem) -{ - return 0; -} - #endif /* CONFIG_CGROUP_MEM_CONT */ #endif /* _LINUX_MEMCONTROL_H */ diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index bb7288a..cb57d65 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -310,8 +310,6 @@ struct mm_struct { #ifdef CONFIG_MMU_NOTIFIER struct mmu_notifier_mm *mmu_notifier_mm; #endif - /* How many tasks sharing this mm are OOM_DISABLE */ - atomic_t oom_disable_count; }; /* Future-safe accessor for struct mm_struct's cpu_vm_mask. */ diff --git a/include/linux/oom.h b/include/linux/oom.h index 5e3aa83..40e5e3a 100644 --- a/include/linux/oom.h +++ b/include/linux/oom.h @@ -1,27 +1,14 @@ #ifndef __INCLUDE_LINUX_OOM_H #define __INCLUDE_LINUX_OOM_H -/* - * /proc//oom_adj is deprecated, see - * Documentation/feature-removal-schedule.txt. - * - * /proc//oom_adj set to -17 protects from the oom-killer - */ +/* /proc//oom_adj set to -17 protects from the oom-killer */ #define OOM_DISABLE (-17) /* inclusive */ #define OOM_ADJUST_MIN (-16) #define OOM_ADJUST_MAX 15 -/* - * /proc//oom_score_adj set to OOM_SCORE_ADJ_MIN disables oom killing for - * pid. - */ -#define OOM_SCORE_ADJ_MIN (-1000) -#define OOM_SCORE_ADJ_MAX 1000 - #ifdef __KERNEL__ -#include #include #include @@ -40,8 +27,6 @@ enum oom_constraint { CONSTRAINT_MEMCG, }; -extern unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, - const nodemask_t *nodemask, unsigned long totalpages); extern int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags); extern void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags); @@ -66,8 +51,6 @@ static inline void oom_killer_enable(void) extern unsigned long badness(struct task_struct *p, struct mem_cgroup *mem, const nodemask_t *nodemask, unsigned long uptime); -extern struct task_struct *find_lock_task_mm(struct task_struct *p); - /* sysctls */ extern int sysctl_oom_dump_tasks; extern int sysctl_oom_kill_allocating_task; diff --git a/include/linux/sched.h b/include/linux/sched.h index d0036e5..a35acb6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -624,8 +624,7 @@ struct signal_struct { struct tty_audit_buf *tty_audit_buf; #endif - int oom_adj; /* OOM kill score adjustment (bit shift) */ - int oom_score_adj; /* OOM kill score adjustment */ + int oom_adj; /* OOM kill score adjustment (bit shift) */ struct mutex cred_guard_mutex; /* guard against foreign influences on * credential calculations diff --git a/kernel/exit.c b/kernel/exit.c index 21aa7b3..c806406 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -50,7 +50,6 @@ #include #include #include -#include #include #include @@ -696,8 +695,6 @@ static void exit_mm(struct task_struct * tsk) enter_lazy_tlb(mm, current); /* We don't want this task to be frozen prematurely */ clear_freeze_flag(tsk); - if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) - atomic_dec(&mm->oom_disable_count); task_unlock(tsk); mm_update_next_owner(mm); mmput(mm); diff --git a/kernel/fork.c b/kernel/fork.c index 3b159c5..cca5e8b 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -65,7 +65,6 @@ #include #include #include -#include #include #include @@ -489,7 +488,6 @@ static struct mm_struct * mm_init(struct mm_struct * mm, struct task_struct *p) mm->cached_hole_size = ~0UL; mm_init_aio(mm); mm_init_owner(mm, p); - atomic_set(&mm->oom_disable_count, 0); if (likely(!mm_alloc_pgd(mm))) { mm->def_flags = 0; @@ -743,8 +741,6 @@ good_mm: /* Initializing for Swap token stuff */ mm->token_priority = 0; mm->last_interval = 0; - if (tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) - atomic_inc(&mm->oom_disable_count); tsk->mm = mm; tsk->active_mm = mm; @@ -906,7 +902,6 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk) tty_audit_fork(sig); sig->oom_adj = current->signal->oom_adj; - sig->oom_score_adj = current->signal->oom_score_adj; mutex_init(&sig->cred_guard_mutex); @@ -1305,13 +1300,8 @@ bad_fork_cleanup_io: bad_fork_cleanup_namespaces: exit_task_namespaces(p); bad_fork_cleanup_mm: - if (p->mm) { - task_lock(p); - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) - atomic_dec(&p->mm->oom_disable_count); - task_unlock(p); + if (p->mm) mmput(p->mm); - } bad_fork_cleanup_signal: if (!(clone_flags & CLONE_THREAD)) free_signal_struct(p->signal); @@ -1704,10 +1694,6 @@ SYSCALL_DEFINE1(unshare, unsigned long, unshare_flags) active_mm = current->active_mm; current->mm = new_mm; current->active_mm = new_mm; - if (current->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { - atomic_dec(&mm->oom_disable_count); - atomic_inc(&new_mm->oom_disable_count); - } activate_mm(active_mm, new_mm); new_mm = mm; } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9a99cfa..c628370 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -47,7 +47,6 @@ #include #include #include -#include #include "internal.h" #include @@ -917,13 +916,10 @@ int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) { int ret; struct mem_cgroup *curr = NULL; - struct task_struct *p; - p = find_lock_task_mm(task); - if (!p) - return 0; - curr = try_get_mem_cgroup_from_mm(p->mm); - task_unlock(p); + task_lock(task); + curr = try_get_mem_cgroup_from_mm(task->mm); + task_unlock(task); if (!curr) return 0; /* @@ -1297,24 +1293,6 @@ static int mem_cgroup_count_children(struct mem_cgroup *mem) } /* - * Return the memory (and swap, if configured) limit for a memcg. - */ -u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) -{ - u64 limit; - u64 memsw; - - limit = res_counter_read_u64(&memcg->res, RES_LIMIT) + - total_swap_pages; - memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); - /* - * If memsw is finite and limits the amount of swap space available - * to this memcg, return that limit. - */ - return min(limit, memsw); -} - -/* * Visit the first child (need not be the first child as per the ordering * of the cgroup list, since we track last_scanned_child) of @mem and use * that to reclaim free pages from. diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 7dcca55..f251ddb 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -4,8 +4,6 @@ * Copyright (C) 1998,2000 Rik van Riel * Thanks go out to Claus Fischer for some serious inspiration and * for goading me into coding this file... - * Copyright (C) 2010 Google, Inc. - * Rewritten by David Rientjes * * The routines in this file are used to kill a process when * we're seriously out of memory. This gets called from __alloc_pages() @@ -36,6 +34,7 @@ int sysctl_panic_on_oom; int sysctl_oom_kill_allocating_task; int sysctl_oom_dump_tasks = 1; static DEFINE_SPINLOCK(zone_scan_lock); +/* #define DEBUG */ #ifdef CONFIG_NUMA /** @@ -106,7 +105,7 @@ static void boost_dying_task_prio(struct task_struct *p, * pointer. Return p, or any of its subthreads with a valid ->mm, with * task_lock() held. */ -struct task_struct *find_lock_task_mm(struct task_struct *p) +static struct task_struct *find_lock_task_mm(struct task_struct *p) { struct task_struct *t = p; @@ -121,8 +120,8 @@ struct task_struct *find_lock_task_mm(struct task_struct *p) } /* return true if the task is not adequate as candidate victim task. */ -static bool oom_unkillable_task(struct task_struct *p, - const struct mem_cgroup *mem, const nodemask_t *nodemask) +static bool oom_unkillable_task(struct task_struct *p, struct mem_cgroup *mem, + const nodemask_t *nodemask) { if (is_global_init(p)) return true; @@ -141,82 +140,137 @@ static bool oom_unkillable_task(struct task_struct *p, } /** - * oom_badness - heuristic function to determine which candidate task to kill + * badness - calculate a numeric value for how bad this task has been * @p: task struct of which task we should calculate - * @totalpages: total present RAM allowed for page allocation + * @uptime: current uptime in seconds * - * The heuristic for determining which task to kill is made to be as simple and - * predictable as possible. The goal is to return the highest value for the - * task consuming the most memory to avoid subsequent oom failures. + * The formula used is relatively simple and documented inline in the + * function. The main rationale is that we want to select a good task + * to kill when we run out of memory. + * + * Good in this context means that: + * 1) we lose the minimum amount of work done + * 2) we recover a large amount of memory + * 3) we don't kill anything innocent of eating tons of memory + * 4) we want to kill the minimum amount of processes (one) + * 5) we try to kill the process the user expects us to kill, this + * algorithm has been meticulously tuned to meet the principle + * of least surprise ... (be careful when you change it) */ -unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, - const nodemask_t *nodemask, unsigned long totalpages) +unsigned long badness(struct task_struct *p, struct mem_cgroup *mem, + const nodemask_t *nodemask, unsigned long uptime) { - int points; + unsigned long points, cpu_time, run_time; + struct task_struct *child; + struct task_struct *c, *t; + int oom_adj = p->signal->oom_adj; + struct task_cputime task_time; + unsigned long utime; + unsigned long stime; if (oom_unkillable_task(p, mem, nodemask)) return 0; + if (oom_adj == OOM_DISABLE) + return 0; p = find_lock_task_mm(p); if (!p) return 0; /* - * Shortcut check for a thread sharing p->mm that is OOM_SCORE_ADJ_MIN - * so the entire heuristic doesn't need to be executed for something - * that cannot be killed. + * The memory size of the process is the basis for the badness. */ - if (atomic_read(&p->mm->oom_disable_count)) { - task_unlock(p); - return 0; - } + points = p->mm->total_vm; + task_unlock(p); /* - * When the PF_OOM_ORIGIN bit is set, it indicates the task should have - * priority for oom killing. + * swapoff can easily use up all memory, so kill those first. */ - if (p->flags & PF_OOM_ORIGIN) { - task_unlock(p); - return 1000; - } + if (p->flags & PF_OOM_ORIGIN) + return ULONG_MAX; /* - * The memory controller may have a limit of 0 bytes, so avoid a divide - * by zero, if necessary. + * Processes which fork a lot of child processes are likely + * a good choice. We add half the vmsize of the children if they + * have an own mm. This prevents forking servers to flood the + * machine with an endless amount of children. In case a single + * child is eating the vast majority of memory, adding only half + * to the parents will make the child our kill candidate of choice. */ - if (!totalpages) - totalpages = 1; + t = p; + do { + list_for_each_entry(c, &t->children, sibling) { + child = find_lock_task_mm(c); + if (child) { + if (child->mm != p->mm) + points += child->mm->total_vm/2 + 1; + task_unlock(child); + } + } + } while_each_thread(p, t); /* - * The baseline for the badness score is the proportion of RAM that each - * task's rss and swap space use. + * CPU time is in tens of seconds and run time is in thousands + * of seconds. There is no particular reason for this other than + * that it turned out to work very well in practice. */ - points = (get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS)) * 1000 / - totalpages; - task_unlock(p); + thread_group_cputime(p, &task_time); + utime = cputime_to_jiffies(task_time.utime); + stime = cputime_to_jiffies(task_time.stime); + cpu_time = (utime + stime) >> (SHIFT_HZ + 3); + + + if (uptime >= p->start_time.tv_sec) + run_time = (uptime - p->start_time.tv_sec) >> 10; + else + run_time = 0; + + if (cpu_time) + points /= int_sqrt(cpu_time); + if (run_time) + points /= int_sqrt(int_sqrt(run_time)); /* - * Root processes get 3% bonus, just like the __vm_enough_memory() - * implementation used by LSMs. + * Niced processes are most likely less important, so double + * their badness points. */ - if (has_capability_noaudit(p, CAP_SYS_ADMIN)) - points -= 30; + if (task_nice(p) > 0) + points *= 2; /* - * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may - * either completely disable oom killing or always prefer a certain - * task. + * Superuser processes are usually more important, so we make it + * less likely that we kill those. */ - points += p->signal->oom_score_adj; + if (has_capability_noaudit(p, CAP_SYS_ADMIN) || + has_capability_noaudit(p, CAP_SYS_RESOURCE)) + points /= 4; /* - * Never return 0 for an eligible task that may be killed since it's - * possible that no single user task uses more than 0.1% of memory and - * no single admin tasks uses more than 3.0%. + * We don't want to kill a process with direct hardware access. + * Not only could that mess up the hardware, but usually users + * tend to only have this flag set on applications they think + * of as important. */ - if (points <= 0) - return 1; - return (points < 1000) ? points : 1000; + if (has_capability_noaudit(p, CAP_SYS_RAWIO)) + points /= 4; + + /* + * Adjust the score by oom_adj. + */ + if (oom_adj) { + if (oom_adj > 0) { + if (!points) + points = 1; + points <<= oom_adj; + } else + points >>= -(oom_adj); + } + +#ifdef DEBUG + printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", + p->pid, p->comm, points); +#endif + return points; } /* @@ -224,20 +278,12 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, */ #ifdef CONFIG_NUMA static enum oom_constraint constrained_alloc(struct zonelist *zonelist, - gfp_t gfp_mask, nodemask_t *nodemask, - unsigned long *totalpages) + gfp_t gfp_mask, nodemask_t *nodemask) { struct zone *zone; struct zoneref *z; enum zone_type high_zoneidx = gfp_zone(gfp_mask); - bool cpuset_limited = false; - int nid; - - /* Default to all available memory */ - *totalpages = totalram_pages + total_swap_pages; - if (!zonelist) - return CONSTRAINT_NONE; /* * Reach here only when __GFP_NOFAIL is used. So, we should avoid * to kill current.We have to random task kill in this case. @@ -247,37 +293,26 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist, return CONSTRAINT_NONE; /* - * This is not a __GFP_THISNODE allocation, so a truncated nodemask in - * the page allocator means a mempolicy is in effect. Cpuset policy - * is enforced in get_page_from_freelist(). + * The nodemask here is a nodemask passed to alloc_pages(). Now, + * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy + * feature. mempolicy is an only user of nodemask here. + * check mempolicy's nodemask contains all N_HIGH_MEMORY */ - if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) { - *totalpages = total_swap_pages; - for_each_node_mask(nid, *nodemask) - *totalpages += node_spanned_pages(nid); + if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) return CONSTRAINT_MEMORY_POLICY; - } /* Check this allocation failure is caused by cpuset's wall function */ for_each_zone_zonelist_nodemask(zone, z, zonelist, high_zoneidx, nodemask) if (!cpuset_zone_allowed_softwall(zone, gfp_mask)) - cpuset_limited = true; + return CONSTRAINT_CPUSET; - if (cpuset_limited) { - *totalpages = total_swap_pages; - for_each_node_mask(nid, cpuset_current_mems_allowed) - *totalpages += node_spanned_pages(nid); - return CONSTRAINT_CPUSET; - } return CONSTRAINT_NONE; } #else static enum oom_constraint constrained_alloc(struct zonelist *zonelist, - gfp_t gfp_mask, nodemask_t *nodemask, - unsigned long *totalpages) + gfp_t gfp_mask, nodemask_t *nodemask) { - *totalpages = totalram_pages + total_swap_pages; return CONSTRAINT_NONE; } #endif @@ -288,16 +323,17 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist, * * (not docbooked, we don't want this one cluttering up the manual) */ -static struct task_struct *select_bad_process(unsigned int *ppoints, - unsigned long totalpages, struct mem_cgroup *mem, - const nodemask_t *nodemask) +static struct task_struct *select_bad_process(unsigned long *ppoints, + struct mem_cgroup *mem, const nodemask_t *nodemask) { struct task_struct *p; struct task_struct *chosen = NULL; + struct timespec uptime; *ppoints = 0; + do_posix_clock_monotonic_gettime(&uptime); for_each_process(p) { - unsigned int points; + unsigned long points; if (oom_unkillable_task(p, mem, nodemask)) continue; @@ -329,11 +365,11 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, return ERR_PTR(-1UL); chosen = p; - *ppoints = 1000; + *ppoints = ULONG_MAX; } - points = oom_badness(p, mem, nodemask, totalpages); - if (points > *ppoints) { + points = badness(p, mem, nodemask, uptime.tv_sec); + if (points > *ppoints || !chosen) { chosen = p; *ppoints = points; } @@ -345,24 +381,27 @@ static struct task_struct *select_bad_process(unsigned int *ppoints, /** * dump_tasks - dump current memory state of all system tasks * @mem: current's memory controller, if constrained - * @nodemask: nodemask passed to page allocator for mempolicy ooms * - * Dumps the current memory state of all eligible tasks. Tasks not in the same - * memcg, not in the same cpuset, or bound to a disjoint set of mempolicy nodes - * are not shown. + * Dumps the current memory state of all system tasks, excluding kernel threads. * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj - * value, oom_score_adj value, and name. + * score, and name. + * + * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are + * shown. * * Call with tasklist_lock read-locked. */ -static void dump_tasks(const struct mem_cgroup *mem, const nodemask_t *nodemask) +static void dump_tasks(const struct mem_cgroup *mem) { struct task_struct *p; struct task_struct *task; - pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n"); + printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj " + "name\n"); for_each_process(p) { - if (oom_unkillable_task(p, mem, nodemask)) + if (p->flags & PF_KTHREAD) + continue; + if (mem && !task_in_mem_cgroup(p, mem)) continue; task = find_lock_task_mm(p); @@ -375,69 +414,43 @@ static void dump_tasks(const struct mem_cgroup *mem, const nodemask_t *nodemask) continue; } - pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n", + pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %s\n", task->pid, task_uid(task), task->tgid, task->mm->total_vm, get_mm_rss(task->mm), - task_cpu(task), task->signal->oom_adj, - task->signal->oom_score_adj, task->comm); + task_cpu(task), task->signal->oom_adj, task->comm); task_unlock(task); } } static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, - struct mem_cgroup *mem, const nodemask_t *nodemask) + struct mem_cgroup *mem) { task_lock(current); pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " - "oom_adj=%d, oom_score_adj=%d\n", - current->comm, gfp_mask, order, current->signal->oom_adj, - current->signal->oom_score_adj); + "oom_adj=%d\n", + current->comm, gfp_mask, order, current->signal->oom_adj); cpuset_print_task_mems_allowed(current); task_unlock(current); dump_stack(); mem_cgroup_print_oom_info(mem, p); show_mem(); if (sysctl_oom_dump_tasks) - dump_tasks(mem, nodemask); + dump_tasks(mem); } #define K(x) ((x) << (PAGE_SHIFT-10)) static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) { - struct task_struct *q; - struct mm_struct *mm; - p = find_lock_task_mm(p); if (!p) return 1; - /* mm cannot be safely dereferenced after task_unlock(p) */ - mm = p->mm; - pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n", task_pid_nr(p), p->comm, K(p->mm->total_vm), K(get_mm_counter(p->mm, MM_ANONPAGES)), K(get_mm_counter(p->mm, MM_FILEPAGES))); task_unlock(p); - /* - * Kill all processes sharing p->mm in other thread groups, if any. - * They don't get access to memory reserves or a higher scheduler - * priority, though, to avoid depletion of all memory or task - * starvation. This prevents mm->mmap_sem livelock when an oom killed - * task cannot exit because it requires the semaphore and its contended - * by another thread trying to allocate memory itself. That thread will - * now get access to memory reserves since it has a pending fatal - * signal. - */ - for_each_process(q) - if (q->mm == mm && !same_thread_group(q, p)) { - task_lock(q); /* Protect ->comm from prctl() */ - pr_err("Kill process %d (%s) sharing same memory\n", - task_pid_nr(q), q->comm); - task_unlock(q); - force_sig(SIGKILL, q); - } set_tsk_thread_flag(p, TIF_MEMDIE); force_sig(SIGKILL, p); @@ -454,17 +467,17 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem) #undef K static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, - unsigned int points, unsigned long totalpages, - struct mem_cgroup *mem, nodemask_t *nodemask, - const char *message) + unsigned long points, struct mem_cgroup *mem, + nodemask_t *nodemask, const char *message) { struct task_struct *victim = p; struct task_struct *child; struct task_struct *t = p; - unsigned int victim_points = 0; + unsigned long victim_points = 0; + struct timespec uptime; if (printk_ratelimit()) - dump_header(p, gfp_mask, order, mem, nodemask); + dump_header(p, gfp_mask, order, mem); /* * If the task is already exiting, don't alarm the sysadmin or kill @@ -477,7 +490,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, } task_lock(p); - pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n", + pr_err("%s: Kill process %d (%s) score %lu or sacrifice child\n", message, task_pid_nr(p), p->comm, points); task_unlock(p); @@ -487,15 +500,14 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, * parent. This attempts to lose the minimal amount of work done while * still freeing memory. */ + do_posix_clock_monotonic_gettime(&uptime); do { list_for_each_entry(child, &t->children, sibling) { - unsigned int child_points; + unsigned long child_points; - /* - * oom_badness() returns 0 if the thread is unkillable - */ - child_points = oom_badness(child, mem, nodemask, - totalpages); + /* badness() returns 0 if the thread is unkillable */ + child_points = badness(child, mem, nodemask, + uptime.tv_sec); if (child_points > victim_points) { victim = child; victim_points = child_points; @@ -510,7 +522,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, * Determines whether the kernel must panic because of the panic_on_oom sysctl. */ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, - int order, const nodemask_t *nodemask) + int order) { if (likely(!sysctl_panic_on_oom)) return; @@ -524,7 +536,7 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, return; } read_lock(&tasklist_lock); - dump_header(NULL, gfp_mask, order, NULL, nodemask); + dump_header(NULL, gfp_mask, order, NULL); read_unlock(&tasklist_lock); panic("Out of memory: %s panic_on_oom is enabled\n", sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); @@ -533,19 +545,17 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask, #ifdef CONFIG_CGROUP_MEM_RES_CTLR void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) { - unsigned long limit; - unsigned int points = 0; + unsigned long points = 0; struct task_struct *p; - check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); - limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT; + check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0); read_lock(&tasklist_lock); retry: - p = select_bad_process(&points, limit, mem, NULL); + p = select_bad_process(&points, mem, NULL); if (!p || PTR_ERR(p) == -1UL) goto out; - if (oom_kill_process(p, gfp_mask, 0, points, limit, mem, NULL, + if (oom_kill_process(p, gfp_mask, 0, points, mem, NULL, "Memory cgroup out of memory")) goto retry; out: @@ -669,11 +679,9 @@ static void clear_system_oom(void) void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order, nodemask_t *nodemask) { - const nodemask_t *mpol_mask; struct task_struct *p; - unsigned long totalpages; unsigned long freed = 0; - unsigned int points; + unsigned long points; enum oom_constraint constraint = CONSTRAINT_NONE; int killed = 0; @@ -697,40 +705,41 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, * Check if there were limitations on the allocation (only relevant for * NUMA) that may require different handling. */ - constraint = constrained_alloc(zonelist, gfp_mask, nodemask, - &totalpages); - mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL; - check_panic_on_oom(constraint, gfp_mask, order, mpol_mask); + if (zonelist) + constraint = constrained_alloc(zonelist, gfp_mask, nodemask); + check_panic_on_oom(constraint, gfp_mask, order); read_lock(&tasklist_lock); if (sysctl_oom_kill_allocating_task && !oom_unkillable_task(current, NULL, nodemask) && - current->mm && !atomic_read(¤t->mm->oom_disable_count)) { + (current->signal->oom_adj != OOM_DISABLE)) { /* * oom_kill_process() needs tasklist_lock held. If it returns * non-zero, current could not be killed so we must fallback to * the tasklist scan. */ - if (!oom_kill_process(current, gfp_mask, order, 0, totalpages, - NULL, nodemask, + if (!oom_kill_process(current, gfp_mask, order, 0, NULL, + nodemask, "Out of memory (oom_kill_allocating_task)")) goto out; } retry: - p = select_bad_process(&points, totalpages, NULL, mpol_mask); + p = select_bad_process(&points, NULL, + constraint == CONSTRAINT_MEMORY_POLICY ? nodemask : + NULL); if (PTR_ERR(p) == -1UL) goto out; /* Found nothing?!?! Either we hang forever, or we panic. */ if (!p) { - dump_header(NULL, gfp_mask, order, NULL, mpol_mask); + dump_header(NULL, gfp_mask, order, NULL); read_unlock(&tasklist_lock); panic("Out of memory and no killable processes...\n"); } - if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL, - nodemask, "Out of memory")) + if (oom_kill_process(p, gfp_mask, order, points, NULL, nodemask, + "Out of memory")) goto retry; killed = 1; out: -- 1.6.5.2