#include <linux/jiffies.h>
#include <linux/cpuset.h>
+int sysctl_panic_on_oom;
/* #define DEBUG */
/**
- * oom_badness - calculate a numeric value for how bad this task has been
+ * badness - calculate a numeric value for how bad this task has been
* @p: task struct of which task we should calculate
* @uptime: current uptime in seconds
*
return 0;
}
+ /*
+ * 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.
*/
if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO))
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.
*/
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 for wait it
+ * 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) {
* CAP_SYS_RAW_IO set, send SIGTERM instead (but it's unlikely that
* we select a process with CAP_SYS_RAW_IO set).
*/
-static void __oom_kill_task(task_t *p, const char *message)
+static void __oom_kill_task(struct task_struct *p, const char *message)
{
if (p->pid == 1) {
WARN_ON(1);
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);
/*
force_sig(SIGKILL, p);
}
-static int oom_kill_task(task_t *p, const char *message)
+static int oom_kill_task(struct task_struct *p, const char *message)
{
struct mm_struct *mm;
- task_t * g, * q;
+ struct task_struct *g, *q;
mm = p->mm;
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;
+ }
+
/* Try to kill a child first */
list_for_each(tsk, &p->children) {
c = list_entry(tsk, struct task_struct, sibling);
return oom_kill_task(p, message);
}
+int should_oom_kill(void)
+{
+ static spinlock_t oom_lock = SPIN_LOCK_UNLOCKED;
+ static unsigned long first, last, count, lastkill;
+ unsigned long now, since;
+ int ret = 0;
+
+ spin_lock(&oom_lock);
+ now = jiffies;
+ since = now - last;
+ last = now;
+
+ /*
+ * If it's been a long time since last failure,
+ * we're not oom.
+ */
+ if (since > 5*HZ)
+ goto reset;
+
+ /*
+ * If we haven't tried for at least one second,
+ * we're not really oom.
+ */
+ since = now - first;
+ if (since < HZ)
+ goto out_unlock;
+
+ /*
+ * If we have gotten only a few failures,
+ * we're not really oom.
+ */
+ if (++count < 10)
+ goto out_unlock;
+
+ /*
+ * If we just killed a process, wait a while
+ * to give that task a chance to exit. This
+ * avoids killing multiple processes needlessly.
+ */
+ since = now - lastkill;
+ if (since < HZ*5)
+ goto out_unlock;
+
+ /*
+ * Ok, really out of memory. Kill something.
+ */
+ lastkill = now;
+ ret = 1;
+
+reset:
+/*
+ * We dropped the lock above, so check to be sure the variable
+ * first only ever increases to prevent false OOM's.
+ */
+ if (time_after(now, first))
+ first = now;
+ count = 0;
+
+out_unlock:
+ spin_unlock(&oom_lock);
+ return ret;
+}
+
/**
- * oom_kill - kill the "best" process when we run out of memory
+ * out_of_memory - kill the "best" process when we run out of memory
*
* If we run out of memory, we have the choice between either
* killing a random task (bad), letting the system crash (worse)
*/
void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
{
- task_t *p;
+ struct task_struct *p;
unsigned long points = 0;
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();
}
+ if (!should_oom_kill())
+ return;
+
cpuset_lock();
read_lock(&tasklist_lock);
break;
case CONSTRAINT_NONE:
+ if (sysctl_panic_on_oom)
+ panic("out of memory. panic_on_oom is selected\n");
retry:
/*
* Rambo mode: Shoot down a process and hope it solves whatever
git://git.onelab.eu / linux-2.6.git / blobdiff