* kernel subsystems and hints as to where to find out what things do.
*/
+#include <linux/oom.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/swap.h>
#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 */
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.
*/
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;
do_posix_clock_monotonic_gettime(&uptime);
do_each_thread(g, p) {
unsigned long points;
- int releasing;
- /* skip the init task with pid == 1 */
- if (p->pid == 1)
- continue;
- if (p->oomkilladj == OOM_DISABLE)
+ /*
+ * skip kernel threads and tasks which have already released
+ * their mm.
+ */
+ if (!p->mm)
continue;
- /* If p's nodes don't overlap ours, it won't help to kill p. */
- if (!cpuset_excl_nodes_overlap(p))
+ /* skip the init task */
+ if (is_init(p))
continue;
+ /*
+ * This task already has access to memory reserves and is
+ * being killed. Don't allow any other task access to the
+ * memory reserve.
+ *
+ * Note: this may have a chance of deadlock if it gets
+ * blocked waiting for another task which itself is waiting
+ * for memory. Is there a better alternative?
+ */
+ if (test_tsk_thread_flag(p, TIF_MEMDIE))
+ return ERR_PTR(-1UL);
+
/*
* 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 easy OOM deadlock.
*/
- releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
- p->flags & PF_EXITING;
- if (releasing && !(p->flags & PF_DEAD))
- return ERR_PTR(-1UL);
- if (p->flags & PF_SWAPOFF)
- return p;
+ if (p->flags & PF_EXITING) {
+ if (p != current)
+ return ERR_PTR(-1UL);
+
+ chosen = p;
+ *ppoints = ULONG_MAX;
+ }
+
+ if (p->oomkilladj == OOM_DISABLE)
+ continue;
points = badness(p, uptime.tv_sec);
if (points > *ppoints || !chosen) {
*ppoints = points;
}
} while_each_thread(g, p);
+
return chosen;
}
/**
- * 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)
+static void __oom_kill_task(struct task_struct *p, int verbose)
{
- if (p->pid == 1) {
+ if (is_init(p)) {
WARN_ON(1);
printk(KERN_WARNING "tried to kill init!\n");
return;
}
- task_lock(p);
- if (!p->mm || p->mm == &init_mm) {
+ if (!p->mm) {
WARN_ON(1);
printk(KERN_WARNING "tried to kill an mm-less task!\n");
- task_unlock(p);
return;
}
- task_unlock(p);
- printk(KERN_ERR "%s: Killed process %d (%s).\n",
- message, p->pid, p->comm);
+
+ if (verbose)
+ printk(KERN_ERR "Killed process %d (%s)\n", p->pid, p->comm);
/*
* We give our sacrificial lamb high priority and access to
force_sig(SIGKILL, p);
}
-static int oom_kill_task(struct task_struct *p, const char *message)
+static int oom_kill_task(struct task_struct *p)
{
struct mm_struct *mm;
struct task_struct *g, *q;
* However, this is of no concern to us.
*/
- if (mm == NULL || mm == &init_mm)
+ if (mm == NULL)
return 1;
- __oom_kill_task(p, message);
+ /*
+ * Don't kill the process if any threads are set to OOM_DISABLE
+ */
+ do_each_thread(g, q) {
+ if (q->mm == mm && p->oomkilladj == OOM_DISABLE)
+ return 1;
+ } while_each_thread(g, q);
+
+ __oom_kill_task(p, 1);
+
/*
* kill all processes that share the ->mm (i.e. all threads),
- * but are in a different thread group
+ * but are in a different thread group.
*/
- do_each_thread(g, q)
+ do_each_thread(g, q) {
if (q->mm == mm && q->tgid != p->tgid)
- __oom_kill_task(q, message);
- while_each_thread(g, q);
+ __oom_kill_task(q, 1);
+ } while_each_thread(g, q);
return 0;
}
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, 0);
+ return 0;
+ }
+
+ printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n",
+ message, 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);
if (c->mm == p->mm)
continue;
- if (!oom_kill_task(c, message))
+ if (!oom_kill_task(c))
return 0;
}
- return oom_kill_task(p, message);
+ return oom_kill_task(p);
+}
+
+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
{
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();
}
git.openpandora.org / pandora-kernel.git / blobdiff