* kernel subsystems and hints as to where to find out what things do.
*/
+#include <linux/oom.h>
#include <linux/mm.h>
+#include <linux/err.h>
#include <linux/sched.h>
#include <linux/swap.h>
#include <linux/timex.h>
#include <linux/cpuset.h>
#include <linux/module.h>
#include <linux/notifier.h>
+#include <linux/memcontrol.h>
+#include <linux/security.h>
int sysctl_panic_on_oom;
+int sysctl_oom_kill_allocating_task;
+int sysctl_oom_dump_tasks;
+static DEFINE_SPINLOCK(zone_scan_lock);
/* #define DEBUG */
/**
}
/*
- * 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;
task_unlock(p);
/*
+ * swapoff can easily use up all memory, so kill those first.
+ */
+ if (p->flags & PF_SWAPOFF)
+ 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
* Superuser processes are usually more important, so we make it
* less likely that we kill those.
*/
- if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_ADMIN) ||
- p->uid == 0 || p->euid == 0)
+ if (has_capability_noaudit(p, CAP_SYS_ADMIN) ||
+ has_capability_noaudit(p, CAP_SYS_RESOURCE))
points /= 4;
/*
* tend to only have this flag set on applications they think
* of as important.
*/
- if (cap_t(p->cap_effective) & CAP_TO_MASK(CAP_SYS_RAWIO))
+ if (has_capability_noaudit(p, CAP_SYS_RAWIO))
points /= 4;
/*
* 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))
+ if (!cpuset_mems_allowed_intersects(current, p))
points /= 8;
/*
* Adjust the score by oomkilladj.
*/
if (p->oomkilladj) {
- if (p->oomkilladj > 0)
+ if (p->oomkilladj > 0) {
+ if (!points)
+ points = 1;
points <<= p->oomkilladj;
- else
+ } else
points >>= -(p->oomkilladj);
}
#ifdef DEBUG
- printk(KERN_DEBUG "OOMkill: task %d (%s) got %d points\n",
+ printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n",
p->pid, p->comm, points);
#endif
return points;
}
/*
- * Types of limitations to the nodes from which allocations may occur
- */
-#define CONSTRAINT_NONE 1
-#define CONSTRAINT_MEMORY_POLICY 2
-#define CONSTRAINT_CPUSET 3
-
-/*
* Determine the type of allocation constraint.
*/
-static inline int constrained_alloc(struct zonelist *zonelist, gfp_t gfp_mask)
+static inline enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+ gfp_t gfp_mask)
{
#ifdef CONFIG_NUMA
- struct zone **z;
- nodemask_t nodes = node_online_map;
-
- for (z = zonelist->zones; *z; z++)
- if (cpuset_zone_allowed(*z, gfp_mask))
- node_clear((*z)->zone_pgdat->node_id,
- nodes);
+ struct zone *zone;
+ struct zoneref *z;
+ enum zone_type high_zoneidx = gfp_zone(gfp_mask);
+ nodemask_t nodes = node_states[N_HIGH_MEMORY];
+
+ for_each_zone_zonelist(zone, z, zonelist, high_zoneidx)
+ if (cpuset_zone_allowed_softwall(zone, gfp_mask))
+ node_clear(zone_to_nid(zone), nodes);
else
return CONSTRAINT_CPUSET;
*
* (not docbooked, we don't want this one cluttering up the manual)
*/
-static struct task_struct *select_bad_process(unsigned long *ppoints)
+static struct task_struct *select_bad_process(unsigned long *ppoints,
+ struct mem_cgroup *mem)
{
struct task_struct *g, *p;
struct task_struct *chosen = NULL;
do_posix_clock_monotonic_gettime(&uptime);
do_each_thread(g, p) {
unsigned long points;
- int releasing;
- /* skip kernel threads */
+ /*
+ * skip kernel threads and tasks which have already released
+ * their mm.
+ */
if (!p->mm)
continue;
- /* skip the init task with pid == 1 */
- if (p->pid == 1)
+ /* skip the init task */
+ if (is_global_init(p))
+ continue;
+ if (mem && !task_in_mem_cgroup(p, mem))
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.
*
* 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.
+ * Otherwise we could get an easy OOM deadlock.
*/
- releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
- p->flags & PF_EXITING;
- 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_EXITING) {
+ if (p != current)
+ return ERR_PTR(-1UL);
+
+ chosen = p;
+ *ppoints = ULONG_MAX;
}
+
if (p->oomkilladj == OOM_DISABLE)
continue;
*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).
+ * dump_tasks - dump current memory state of all system tasks
+ * @mem: target memory controller
+ *
+ * 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.
+ *
+ * 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)
+{
+ struct task_struct *g, *p;
+
+ printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
+ "name\n");
+ do_each_thread(g, p) {
+ /*
+ * total_vm and rss sizes do not exist for tasks with a
+ * detached mm so there's no need to report them.
+ */
+ if (!p->mm)
+ continue;
+ if (mem && !task_in_mem_cgroup(p, mem))
+ continue;
+ if (!thread_group_leader(p))
+ continue;
+
+ task_lock(p);
+ printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
+ p->pid, __task_cred(p)->uid, p->tgid,
+ p->mm->total_vm, get_mm_rss(p->mm), (int)task_cpu(p),
+ p->oomkilladj, p->comm);
+ task_unlock(p);
+ } while_each_thread(g, p);
+}
+
+/*
+ * 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_global_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);
- if (message) {
- printk(KERN_ERR "%s: Killed process %d (%s).\n",
- message, p->pid, p->comm);
- }
+ if (verbose)
+ printk(KERN_ERR "Killed process %d (%s)\n",
+ task_pid_nr(p), p->comm);
/*
* We give our sacrificial lamb high priority and access to
* all the memory it needs. That way it should be able to
* exit() and clear out its resources quickly...
*/
- p->time_slice = HZ;
+ p->rt.time_slice = HZ;
set_tsk_thread_flag(p, TIF_MEMDIE);
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 && q->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. Don't let them have access
+ * to memory reserves though, otherwise we might deplete all memory.
*/
- do_each_thread(g, q)
- if (q->mm == mm && q->tgid != p->tgid)
- __oom_kill_task(q, message);
- while_each_thread(g, q);
+ do_each_thread(g, q) {
+ if (q->mm == mm && !same_thread_group(q, p))
+ force_sig(SIGKILL, q);
+ } while_each_thread(g, q);
return 0;
}
-static int oom_kill_process(struct task_struct *p, unsigned long points,
- const char *message)
+static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
+ unsigned long points, struct mem_cgroup *mem,
+ const char *message)
{
struct task_struct *c;
- struct list_head *tsk;
+
+ if (printk_ratelimit()) {
+ printk(KERN_WARNING "%s invoked oom-killer: "
+ "gfp_mask=0x%x, order=%d, oomkilladj=%d\n",
+ current->comm, gfp_mask, order, current->oomkilladj);
+ task_lock(current);
+ cpuset_print_task_mems_allowed(current);
+ task_unlock(current);
+ dump_stack();
+ show_mem();
+ if (sysctl_oom_dump_tasks)
+ dump_tasks(mem);
+ }
/*
* 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);
+ __oom_kill_task(p, 0);
return 0;
}
- printk(KERN_ERR "Out of Memory: Kill process %d (%s) score %li"
- " and children.\n", p->pid, p->comm, points);
+ printk(KERN_ERR "%s: kill process %d (%s) score %li or a child\n",
+ message, task_pid_nr(p), p->comm, points);
+
/* Try to kill a child first */
- list_for_each(tsk, &p->children) {
- c = list_entry(tsk, struct task_struct, sibling);
+ list_for_each_entry(c, &p->children, 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);
+}
+
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR
+void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
+{
+ unsigned long points = 0;
+ struct task_struct *p;
+
+ read_lock(&tasklist_lock);
+retry:
+ p = select_bad_process(&points, mem);
+ if (PTR_ERR(p) == -1UL)
+ goto out;
+
+ if (!p)
+ p = current;
+
+ if (oom_kill_process(p, gfp_mask, 0, points, mem,
+ "Memory cgroup out of memory"))
+ goto retry;
+out:
+ read_unlock(&tasklist_lock);
}
+#endif
static BLOCKING_NOTIFIER_HEAD(oom_notify_list);
}
EXPORT_SYMBOL_GPL(unregister_oom_notifier);
+/*
+ * Try to acquire the OOM killer lock for the zones in zonelist. Returns zero
+ * if a parallel OOM killing is already taking place that includes a zone in
+ * the zonelist. Otherwise, locks all zones in the zonelist and returns 1.
+ */
+int try_set_zone_oom(struct zonelist *zonelist, gfp_t gfp_mask)
+{
+ struct zoneref *z;
+ struct zone *zone;
+ int ret = 1;
+
+ spin_lock(&zone_scan_lock);
+ for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
+ if (zone_is_oom_locked(zone)) {
+ ret = 0;
+ goto out;
+ }
+ }
+
+ for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
+ /*
+ * Lock each zone in the zonelist under zone_scan_lock so a
+ * parallel invocation of try_set_zone_oom() doesn't succeed
+ * when it shouldn't.
+ */
+ zone_set_flag(zone, ZONE_OOM_LOCKED);
+ }
+
+out:
+ spin_unlock(&zone_scan_lock);
+ return ret;
+}
+
+/*
+ * Clears the ZONE_OOM_LOCKED flag for all zones in the zonelist so that failed
+ * allocation attempts with zonelists containing them may now recall the OOM
+ * killer, if necessary.
+ */
+void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
+{
+ struct zoneref *z;
+ struct zone *zone;
+
+ spin_lock(&zone_scan_lock);
+ for_each_zone_zonelist(zone, z, zonelist, gfp_zone(gfp_mask)) {
+ zone_clear_flag(zone, ZONE_OOM_LOCKED);
+ }
+ spin_unlock(&zone_scan_lock);
+}
+
+/*
+ * Must be called with tasklist_lock held for read.
+ */
+static void __out_of_memory(gfp_t gfp_mask, int order)
+{
+ if (sysctl_oom_kill_allocating_task) {
+ oom_kill_process(current, gfp_mask, order, 0, NULL,
+ "Out of memory (oom_kill_allocating_task)");
+
+ } else {
+ unsigned long points;
+ struct task_struct *p;
+
+retry:
+ /*
+ * Rambo mode: Shoot down a process and hope it solves whatever
+ * issues we may have.
+ */
+ p = select_bad_process(&points, NULL);
+
+ if (PTR_ERR(p) == -1UL)
+ return;
+
+ /* Found nothing?!?! Either we hang forever, or we panic. */
+ if (!p) {
+ read_unlock(&tasklist_lock);
+ panic("Out of memory and no killable processes...\n");
+ }
+
+ if (oom_kill_process(p, gfp_mask, order, points, NULL,
+ "Out of memory"))
+ goto retry;
+ }
+}
+
+/*
+ * pagefault handler calls into here because it is out of memory but
+ * doesn't know exactly how or why.
+ */
+void pagefault_out_of_memory(void)
+{
+ 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 this is from memcg, oom-killer is already invoked.
+ * and not worth to go system-wide-oom.
+ */
+ if (mem_cgroup_oom_called(current))
+ goto rest_and_return;
+
+ if (sysctl_panic_on_oom)
+ panic("out of memory from page fault. panic_on_oom is selected.\n");
+
+ read_lock(&tasklist_lock);
+ __out_of_memory(0, 0); /* unknown gfp_mask and order */
+ read_unlock(&tasklist_lock);
+
+ /*
+ * Give "p" a good chance of killing itself before we
+ * retry to allocate memory.
+ */
+rest_and_return:
+ if (!test_thread_flag(TIF_MEMDIE))
+ schedule_timeout_uninterruptible(1);
+}
+
/**
* out_of_memory - kill the "best" process when we run out of memory
+ * @zonelist: zonelist pointer
+ * @gfp_mask: memory allocation flags
+ * @order: amount of memory being requested as a power of 2
*
* 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)
{
- struct task_struct *p;
- unsigned long points = 0;
unsigned long freed = 0;
+ enum oom_constraint constraint;
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(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();
- }
-
- cpuset_lock();
- read_lock(&tasklist_lock);
+ if (sysctl_panic_on_oom == 2)
+ panic("out of memory. Compulsory panic_on_oom is selected.\n");
/*
* Check if there were limitations on the allocation (only relevant for
* NUMA) that may require different handling.
*/
- switch (constrained_alloc(zonelist, gfp_mask)) {
+ constraint = constrained_alloc(zonelist, gfp_mask);
+ read_lock(&tasklist_lock);
+
+ switch (constraint) {
case CONSTRAINT_MEMORY_POLICY:
- oom_kill_process(current, points,
+ oom_kill_process(current, gfp_mask, order, 0, NULL,
"No available memory (MPOL_BIND)");
break;
- case CONSTRAINT_CPUSET:
- oom_kill_process(current, points,
- "No available memory in cpuset");
- 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
- * issues we may have.
- */
- p = select_bad_process(&points);
-
- if (PTR_ERR(p) == -1UL)
- goto out;
-
- /* Found nothing?!?! Either we hang forever, or we panic. */
- if (!p) {
- read_unlock(&tasklist_lock);
- cpuset_unlock();
- panic("Out of memory and no killable processes...\n");
- }
-
- if (oom_kill_process(p, points, "Out of memory"))
- goto retry;
-
+ /* Fall-through */
+ case CONSTRAINT_CPUSET:
+ __out_of_memory(gfp_mask, order);
break;
}
-out:
read_unlock(&tasklist_lock);
- cpuset_unlock();
/*
* Give "p" a good chance of killing itself before we
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff