diff options
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 259 |
1 files changed, 111 insertions, 148 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 0a4ca8a0234b..d3def05a33d9 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -4,6 +4,8 @@ * 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() @@ -34,7 +36,6 @@ 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 /** @@ -140,137 +141,76 @@ static bool oom_unkillable_task(struct task_struct *p, struct mem_cgroup *mem, } /** - * badness - calculate a numeric value for how bad this task has been + * oom_badness - heuristic function to determine which candidate task to kill * @p: task struct of which task we should calculate - * @uptime: current uptime in seconds + * @totalpages: total present RAM allowed for page allocation * - * 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) + * 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. */ -unsigned long badness(struct task_struct *p, struct mem_cgroup *mem, - const nodemask_t *nodemask, unsigned long uptime) +unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, + const nodemask_t *nodemask, unsigned long totalpages) { - 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; + int points; 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; /* - * The memory size of the process is the basis for the badness. - */ - points = p->mm->total_vm; - task_unlock(p); - - /* - * swapoff can easily use up all memory, so kill those first. - */ - if (p->flags & PF_OOM_ORIGIN) - return ULONG_MAX; - - /* - * 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. + * Shortcut check for OOM_SCORE_ADJ_MIN so the entire heuristic doesn't + * need to be executed for something that cannot be killed. */ - 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); + if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { + task_unlock(p); + return 0; + } /* - * 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. + * When the PF_OOM_ORIGIN bit is set, it indicates the task should have + * priority for oom killing. */ - 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)); + if (p->flags & PF_OOM_ORIGIN) { + task_unlock(p); + return 1000; + } /* - * Niced processes are most likely less important, so double - * their badness points. + * The memory controller may have a limit of 0 bytes, so avoid a divide + * by zero, if necessary. */ - if (task_nice(p) > 0) - points *= 2; + if (!totalpages) + totalpages = 1; /* - * Superuser processes are usually more important, so we make it - * less likely that we kill those. + * The baseline for the badness score is the proportion of RAM that each + * task's rss and swap space use. */ - if (has_capability_noaudit(p, CAP_SYS_ADMIN) || - has_capability_noaudit(p, CAP_SYS_RESOURCE)) - points /= 4; + points = (get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS)) * 1000 / + totalpages; + task_unlock(p); /* - * 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. + * Root processes get 3% bonus, just like the __vm_enough_memory() + * implementation used by LSMs. */ - if (has_capability_noaudit(p, CAP_SYS_RAWIO)) - points /= 4; + if (has_capability_noaudit(p, CAP_SYS_ADMIN)) + points -= 30; /* - * Adjust the score by oom_adj. + * /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. */ - if (oom_adj) { - if (oom_adj > 0) { - if (!points) - points = 1; - points <<= oom_adj; - } else - points >>= -(oom_adj); - } + points += p->signal->oom_score_adj; -#ifdef DEBUG - printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n", - p->pid, p->comm, points); -#endif - return points; + if (points < 0) + return 0; + return (points < 1000) ? points : 1000; } /* @@ -278,12 +218,20 @@ unsigned long 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) + gfp_t gfp_mask, nodemask_t *nodemask, + unsigned long *totalpages) { 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. @@ -293,26 +241,37 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist, return CONSTRAINT_NONE; /* - * 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 + * 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(). */ - if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) + 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); 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)) - return CONSTRAINT_CPUSET; + cpuset_limited = true; + 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) + gfp_t gfp_mask, nodemask_t *nodemask, + unsigned long *totalpages) { + *totalpages = totalram_pages + total_swap_pages; return CONSTRAINT_NONE; } #endif @@ -323,17 +282,16 @@ 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 long *ppoints, - struct mem_cgroup *mem, const nodemask_t *nodemask) +static struct task_struct *select_bad_process(unsigned int *ppoints, + unsigned long totalpages, 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 long points; + unsigned int points; if (oom_unkillable_task(p, mem, nodemask)) continue; @@ -365,11 +323,11 @@ static struct task_struct *select_bad_process(unsigned long *ppoints, return ERR_PTR(-1UL); chosen = p; - *ppoints = ULONG_MAX; + *ppoints = 1000; } - points = badness(p, mem, nodemask, uptime.tv_sec); - if (points > *ppoints || !chosen) { + points = oom_badness(p, mem, nodemask, totalpages); + if (points > *ppoints) { chosen = p; *ppoints = points; } @@ -384,7 +342,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints, * * 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 - * score, and name. + * value, oom_score_adj value, and name. * * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are * shown. @@ -396,8 +354,7 @@ static void dump_tasks(const struct mem_cgroup *mem) struct task_struct *p; struct task_struct *task; - printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj " - "name\n"); + pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n"); for_each_process(p) { if (p->flags & PF_KTHREAD) continue; @@ -414,10 +371,11 @@ static void dump_tasks(const struct mem_cgroup *mem) continue; } - printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3u %3d %s\n", - task->pid, __task_cred(task)->uid, task->tgid, - task->mm->total_vm, get_mm_rss(task->mm), - task_cpu(task), task->signal->oom_adj, task->comm); + pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n", + task->pid, __task_cred(task)->uid, 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_unlock(task); } } @@ -427,8 +385,9 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, { task_lock(current); pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " - "oom_adj=%d\n", - current->comm, gfp_mask, order, current->signal->oom_adj); + "oom_adj=%d, oom_score_adj=%d\n", + current->comm, gfp_mask, order, current->signal->oom_adj, + current->signal->oom_score_adj); cpuset_print_task_mems_allowed(current); task_unlock(current); dump_stack(); @@ -468,14 +427,14 @@ 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 long points, struct mem_cgroup *mem, - nodemask_t *nodemask, const char *message) + unsigned int points, unsigned long totalpages, + 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 long victim_points = 0; - struct timespec uptime; + unsigned int victim_points = 0; if (printk_ratelimit()) dump_header(p, gfp_mask, order, mem); @@ -491,7 +450,7 @@ 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 %lu or sacrifice child\n", + pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n", message, task_pid_nr(p), p->comm, points); task_unlock(p); @@ -501,14 +460,15 @@ 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 long child_points; + unsigned int child_points; - /* badness() returns 0 if the thread is unkillable */ - child_points = badness(child, mem, nodemask, - uptime.tv_sec); + /* + * oom_badness() returns 0 if the thread is unkillable + */ + child_points = oom_badness(child, mem, nodemask, + totalpages); if (child_points > victim_points) { victim = child; victim_points = child_points; @@ -546,17 +506,19 @@ 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 points = 0; + unsigned long limit; + unsigned int points = 0; struct task_struct *p; check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0); + limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT; read_lock(&tasklist_lock); retry: - p = select_bad_process(&points, mem, NULL); + p = select_bad_process(&points, limit, mem, NULL); if (!p || PTR_ERR(p) == -1UL) goto out; - if (oom_kill_process(p, gfp_mask, 0, points, mem, NULL, + if (oom_kill_process(p, gfp_mask, 0, points, limit, mem, NULL, "Memory cgroup out of memory")) goto retry; out: @@ -681,8 +643,9 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order, nodemask_t *nodemask) { struct task_struct *p; + unsigned long totalpages; unsigned long freed = 0; - unsigned long points; + unsigned int points; enum oom_constraint constraint = CONSTRAINT_NONE; blocking_notifier_call_chain(&oom_notify_list, 0, &freed); @@ -705,8 +668,8 @@ 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. */ - if (zonelist) - constraint = constrained_alloc(zonelist, gfp_mask, nodemask); + constraint = constrained_alloc(zonelist, gfp_mask, nodemask, + &totalpages); check_panic_on_oom(constraint, gfp_mask, order); read_lock(&tasklist_lock); @@ -718,14 +681,14 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, * non-zero, current could not be killed so we must fallback to * the tasklist scan. */ - if (!oom_kill_process(current, gfp_mask, order, 0, NULL, - nodemask, + if (!oom_kill_process(current, gfp_mask, order, 0, totalpages, + NULL, nodemask, "Out of memory (oom_kill_allocating_task)")) return; } retry: - p = select_bad_process(&points, NULL, + p = select_bad_process(&points, totalpages, NULL, constraint == CONSTRAINT_MEMORY_POLICY ? nodemask : NULL); if (PTR_ERR(p) == -1UL) @@ -738,8 +701,8 @@ retry: panic("Out of memory and no killable processes...\n"); } - if (oom_kill_process(p, gfp_mask, order, points, NULL, nodemask, - "Out of memory")) + if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL, + nodemask, "Out of memory")) goto retry; read_unlock(&tasklist_lock); |