diff options
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 82 |
1 files changed, 55 insertions, 27 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index fc81cb22869..7dcca55ede7 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -121,8 +121,8 @@ 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, struct mem_cgroup *mem, - const nodemask_t *nodemask) +static bool oom_unkillable_task(struct task_struct *p, + const struct mem_cgroup *mem, const nodemask_t *nodemask) { if (is_global_init(p)) return true; @@ -162,10 +162,11 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, return 0; /* - * Shortcut check for OOM_SCORE_ADJ_MIN so the entire heuristic doesn't - * need to be executed for something that cannot be killed. + * 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. */ - if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) { + if (atomic_read(&p->mm->oom_disable_count)) { task_unlock(p); return 0; } @@ -208,8 +209,13 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem, */ points += p->signal->oom_score_adj; - if (points < 0) - return 0; + /* + * 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%. + */ + if (points <= 0) + return 1; return (points < 1000) ? points : 1000; } @@ -339,26 +345,24 @@ 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 system tasks, excluding kernel threads. + * 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. * State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj * 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. - * * Call with tasklist_lock read-locked. */ -static void dump_tasks(const struct mem_cgroup *mem) +static void dump_tasks(const struct mem_cgroup *mem, const nodemask_t *nodemask) { struct task_struct *p; struct task_struct *task; 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; - if (mem && !task_in_mem_cgroup(p, mem)) + if (oom_unkillable_task(p, mem, nodemask)) continue; task = find_lock_task_mm(p); @@ -381,7 +385,7 @@ static void dump_tasks(const struct mem_cgroup *mem) } static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, - struct mem_cgroup *mem) + struct mem_cgroup *mem, const nodemask_t *nodemask) { task_lock(current); pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, " @@ -394,22 +398,46 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order, mem_cgroup_print_oom_info(mem, p); show_mem(); if (sysctl_oom_dump_tasks) - dump_tasks(mem); + dump_tasks(mem, nodemask); } #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); @@ -436,7 +464,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order, unsigned int victim_points = 0; if (printk_ratelimit()) - dump_header(p, gfp_mask, order, mem); + dump_header(p, gfp_mask, order, mem, nodemask); /* * If the task is already exiting, don't alarm the sysadmin or kill @@ -482,7 +510,7 @@ 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) + int order, const nodemask_t *nodemask) { if (likely(!sysctl_panic_on_oom)) return; @@ -496,7 +524,7 @@ 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); + dump_header(NULL, gfp_mask, order, NULL, nodemask); read_unlock(&tasklist_lock); panic("Out of memory: %s panic_on_oom is enabled\n", sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide"); @@ -509,7 +537,7 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask) unsigned int points = 0; struct task_struct *p; - check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0); + check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0, NULL); limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT; read_lock(&tasklist_lock); retry: @@ -641,6 +669,7 @@ 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; @@ -670,12 +699,13 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, */ constraint = constrained_alloc(zonelist, gfp_mask, nodemask, &totalpages); - check_panic_on_oom(constraint, gfp_mask, order); + mpol_mask = (constraint == CONSTRAINT_MEMORY_POLICY) ? nodemask : NULL; + check_panic_on_oom(constraint, gfp_mask, order, mpol_mask); read_lock(&tasklist_lock); if (sysctl_oom_kill_allocating_task && !oom_unkillable_task(current, NULL, nodemask) && - (current->signal->oom_adj != OOM_DISABLE)) { + current->mm && !atomic_read(¤t->mm->oom_disable_count)) { /* * oom_kill_process() needs tasklist_lock held. If it returns * non-zero, current could not be killed so we must fallback to @@ -688,15 +718,13 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, } retry: - p = select_bad_process(&points, totalpages, NULL, - constraint == CONSTRAINT_MEMORY_POLICY ? nodemask : - NULL); + p = select_bad_process(&points, totalpages, NULL, mpol_mask); 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); + dump_header(NULL, gfp_mask, order, NULL, mpol_mask); read_unlock(&tasklist_lock); panic("Out of memory and no killable processes...\n"); } |