diff options
Diffstat (limited to 'mm/oom_kill.c')
| -rw-r--r-- | mm/oom_kill.c | 97 |
1 files changed, 79 insertions, 18 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c index b9af136..bada3d0 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -21,6 +21,8 @@ #include <linux/timex.h> #include <linux/jiffies.h> #include <linux/cpuset.h> +#include <linux/module.h> +#include <linux/notifier.h> int sysctl_panic_on_oom; /* #define DEBUG */ @@ -58,6 +60,12 @@ unsigned long badness(struct task_struct *p, unsigned long uptime) } /* + * swapoff can easily use up all memory, so kill those first. + */ + if (p->flags & PF_SWAPOFF) + return ULONG_MAX; + + /* * The memory size of the process is the basis for the badness. */ points = mm->total_vm; @@ -127,6 +135,14 @@ unsigned long badness(struct task_struct *p, unsigned long uptime) points /= 4; /* + * If p's nodes don't overlap ours, it may still help to kill p + * because p may have allocated or otherwise mapped memory on + * this node before. However it will be less likely. + */ + if (!cpuset_excl_nodes_overlap(p)) + points /= 8; + + /* * Adjust the score by oomkilladj. */ if (p->oomkilladj) { @@ -161,8 +177,7 @@ static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask) for (z = zonelist->zones; *z; z++) if (cpuset_zone_allowed(*z, gfp_mask)) - node_clear((*z)->zone_pgdat->node_id, - nodes); + node_clear(zone_to_nid(*z), nodes); else return CONSTRAINT_CPUSET; @@ -191,25 +206,38 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) unsigned long points; int releasing; + /* skip kernel threads */ + if (!p->mm) + continue; /* skip the init task with pid == 1 */ if (p->pid == 1) continue; - if (p->oomkilladj == OOM_DISABLE) - continue; - /* If p's nodes don't overlap ours, it won't help to kill p. */ - if (!cpuset_excl_nodes_overlap(p)) - continue; /* * This is in the process of releasing memory so wait for it * to finish before killing some other task by mistake. + * + * However, if p is the current task, we allow the 'kill' to + * go ahead if it is exiting: this will simply set TIF_MEMDIE, + * which will allow it to gain access to memory reserves in + * the process of exiting and releasing its resources. + * Otherwise we could get an OOM deadlock. */ releasing = test_tsk_thread_flag(p, TIF_MEMDIE) || p->flags & PF_EXITING; - if (releasing && !(p->flags & PF_DEAD)) + if (releasing) { + /* PF_DEAD tasks have already released their mm */ + if (p->flags & PF_DEAD) + continue; + if (p->flags & PF_EXITING && p == current) { + chosen = p; + *ppoints = ULONG_MAX; + break; + } return ERR_PTR(-1UL); - if (p->flags & PF_SWAPOFF) - return p; + } + if (p->oomkilladj == OOM_DISABLE) + continue; points = badness(p, uptime.tv_sec); if (points > *ppoints || !chosen) { @@ -221,9 +249,9 @@ static struct task_struct *select_bad_process(unsigned long *ppoints) } /** - * We must be careful though to never send SIGKILL a process with - * CAP_SYS_RAW_IO set, send SIGTERM instead (but it's unlikely that - * we select a process with CAP_SYS_RAW_IO set). + * Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO + * flag though it's unlikely that we select a process with CAP_SYS_RAW_IO + * set. */ static void __oom_kill_task(struct task_struct *p, const char *message) { @@ -241,8 +269,11 @@ static void __oom_kill_task(struct task_struct *p, const char *message) return; } task_unlock(p); - printk(KERN_ERR "%s: Killed process %d (%s).\n", + + if (message) { + printk(KERN_ERR "%s: Killed process %d (%s).\n", message, p->pid, p->comm); + } /* * We give our sacrificial lamb high priority and access to @@ -293,8 +324,17 @@ static int oom_kill_process(struct task_struct *p, unsigned long points, struct task_struct *c; struct list_head *tsk; - printk(KERN_ERR "Out of Memory: Kill process %d (%s) score %li and " - "children.\n", p->pid, p->comm, points); + /* + * If the task is already exiting, don't alarm the sysadmin or kill + * its children or threads, just set TIF_MEMDIE so it can die quickly + */ + if (p->flags & PF_EXITING) { + __oom_kill_task(p, NULL); + return 0; + } + + printk(KERN_ERR "Out of Memory: Kill process %d (%s) score %li" + " and children.\n", p->pid, p->comm, points); /* Try to kill a child first */ list_for_each(tsk, &p->children) { c = list_entry(tsk, struct task_struct, sibling); @@ -306,6 +346,20 @@ static int oom_kill_process(struct task_struct *p, unsigned long points, return oom_kill_task(p, message); } +static BLOCKING_NOTIFIER_HEAD(oom_notify_list); + +int register_oom_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&oom_notify_list, nb); +} +EXPORT_SYMBOL_GPL(register_oom_notifier); + +int unregister_oom_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&oom_notify_list, nb); +} +EXPORT_SYMBOL_GPL(unregister_oom_notifier); + /** * out_of_memory - kill the "best" process when we run out of memory * @@ -318,10 +372,17 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) { struct task_struct *p; unsigned long points = 0; + unsigned long freed = 0; + + blocking_notifier_call_chain(&oom_notify_list, 0, &freed); + if (freed > 0) + /* Got some memory back in the last second. */ + return; if (printk_ratelimit()) { - printk("oom-killer: gfp_mask=0x%x, order=%d\n", - gfp_mask, order); + printk(KERN_WARNING "%s invoked oom-killer: " + "gfp_mask=0x%x, order=%d, oomkilladj=%d\n", + current->comm, gfp_mask, order, current->oomkilladj); dump_stack(); show_mem(); } |
