* 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/gfp.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>
+#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 */
+/*
+ * Is all threads of the target process nodes overlap ours?
+ */
+static int has_intersects_mems_allowed(struct task_struct *tsk)
+{
+ struct task_struct *t;
+
+ t = tsk;
+ do {
+ if (cpuset_mems_allowed_intersects(current, t))
+ return 1;
+ t = next_thread(t);
+ } while (t != tsk);
+
+ return 0;
+}
+
/**
- * 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
*
unsigned long badness(struct task_struct *p, unsigned long uptime)
{
- unsigned long points, cpu_time, run_time, s;
- struct list_head *tsk;
+ unsigned long points, cpu_time, run_time;
+ struct mm_struct *mm;
+ struct task_struct *child;
+ int oom_adj = p->signal->oom_adj;
+ struct task_cputime task_time;
+ unsigned long utime;
+ unsigned long stime;
+
+ if (oom_adj == OOM_DISABLE)
+ return 0;
- if (!p->mm)
+ task_lock(p);
+ mm = p->mm;
+ if (!mm) {
+ task_unlock(p);
return 0;
+ }
/*
* The memory size of the process is the basis for the badness.
*/
- points = p->mm->total_vm;
+ points = mm->total_vm;
+
+ /*
+ * After this unlock we can no longer dereference local variable `mm'
+ */
+ task_unlock(p);
+
+ /*
+ * swapoff can easily use up all memory, so kill those first.
+ */
+ if (p->flags & PF_OOM_ORIGIN)
+ return ULONG_MAX;
/*
* Processes which fork a lot of child processes are likely
* child is eating the vast majority of memory, adding only half
* to the parents will make the child our kill candidate of choice.
*/
- list_for_each(tsk, &p->children) {
- struct task_struct *chld;
- chld = list_entry(tsk, struct task_struct, sibling);
- if (chld->mm != p->mm && chld->mm)
- points += chld->mm->total_vm/2 + 1;
+ list_for_each_entry(child, &p->children, sibling) {
+ task_lock(child);
+ if (child->mm != mm && child->mm)
+ points += child->mm->total_vm/2 + 1;
+ task_unlock(child);
}
/*
* of seconds. There is no particular reason for this other than
* that it turned out to work very well in practice.
*/
- cpu_time = (cputime_to_jiffies(p->utime) + cputime_to_jiffies(p->stime))
- >> (SHIFT_HZ + 3);
+ thread_group_cputime(p, &task_time);
+ utime = cputime_to_jiffies(task_time.utime);
+ stime = cputime_to_jiffies(task_time.stime);
+ cpu_time = (utime + stime) >> (SHIFT_HZ + 3);
+
if (uptime >= p->start_time.tv_sec)
run_time = (uptime - p->start_time.tv_sec) >> 10;
else
run_time = 0;
- s = int_sqrt(cpu_time);
- if (s)
- points /= s;
- s = int_sqrt(int_sqrt(run_time));
- if (s)
- points /= s;
+ if (cpu_time)
+ points /= int_sqrt(cpu_time);
+ if (run_time)
+ points /= int_sqrt(int_sqrt(run_time));
/*
* Niced processes are most likely less important, so double
* 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;
/*
- * Adjust the score by oomkilladj.
+ * 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 (!has_intersects_mems_allowed(p))
+ points /= 8;
+
+ /*
+ * Adjust the score by oom_adj.
*/
- if (p->oomkilladj) {
- if (p->oomkilladj > 0)
- points <<= p->oomkilladj;
- else
- points >>= -(p->oomkilladj);
+ if (oom_adj) {
+ if (oom_adj > 0) {
+ if (!points)
+ points = 1;
+ points <<= oom_adj;
+ } else
+ points >>= -(oom_adj);
}
#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;
}
/*
+ * Determine the type of allocation constraint.
+ */
+#ifdef CONFIG_NUMA
+static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+ gfp_t gfp_mask, nodemask_t *nodemask)
+{
+ struct zone *zone;
+ struct zoneref *z;
+ enum zone_type high_zoneidx = gfp_zone(gfp_mask);
+
+ /*
+ * Reach here only when __GFP_NOFAIL is used. So, we should avoid
+ * to kill current.We have to random task kill in this case.
+ * Hopefully, CONSTRAINT_THISNODE...but no way to handle it, now.
+ */
+ if (gfp_mask & __GFP_THISNODE)
+ return CONSTRAINT_NONE;
+
+ /*
+ * The nodemask here is a nodemask passed to alloc_pages(). Now,
+ * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy
+ * feature. mempolicy is an only user of nodemask here.
+ * check mempolicy's nodemask contains all N_HIGH_MEMORY
+ */
+ if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask))
+ return CONSTRAINT_MEMORY_POLICY;
+
+ /* Check this allocation failure is caused by cpuset's wall function */
+ for_each_zone_zonelist_nodemask(zone, z, zonelist,
+ high_zoneidx, nodemask)
+ if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
+ return CONSTRAINT_CPUSET;
+
+ return CONSTRAINT_NONE;
+}
+#else
+static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
+ gfp_t gfp_mask, nodemask_t *nodemask)
+{
+ return CONSTRAINT_NONE;
+}
+#endif
+
+/*
* Simple selection loop. We chose the process with the highest
* number of 'points'. We expect the caller will lock the tasklist.
*
* (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 *p;
struct task_struct *chosen = NULL;
struct timespec uptime;
*ppoints = 0;
do_posix_clock_monotonic_gettime(&uptime);
- do_each_thread(g, p) {
+ for_each_process(p) {
unsigned long points;
- int releasing;
- /* skip the init task with pid == 1 */
- if (p->pid == 1)
+ /*
+ * skip kernel threads and tasks which have already released
+ * their mm.
+ */
+ if (!p->mm)
continue;
- if (p->oomkilladj == OOM_DISABLE)
+ /* skip the init task */
+ if (is_global_init(p))
continue;
- /* If p's nodes don't overlap ours, it won't help to kill p. */
- if (!cpuset_excl_nodes_overlap(p))
+ if (mem && !task_in_mem_cgroup(p, mem))
continue;
/*
- * This is in the process of releasing memory so for wait it
- * to finish before killing some other task by mistake.
+ * 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?
*/
- releasing = test_tsk_thread_flag(p, TIF_MEMDIE) ||
- p->flags & PF_EXITING;
- if (releasing && !(p->flags & PF_DEAD))
+ if (test_tsk_thread_flag(p, TIF_MEMDIE))
return ERR_PTR(-1UL);
- if (p->flags & PF_SWAPOFF)
- return p;
+
+ /*
+ * 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.
+ */
+ if (p->flags & PF_EXITING) {
+ if (p != current)
+ return ERR_PTR(-1UL);
+
+ chosen = p;
+ *ppoints = ULONG_MAX;
+ }
+
+ if (p->signal->oom_adj == OOM_DISABLE)
+ continue;
points = badness(p, uptime.tv_sec);
if (points > *ppoints || !chosen) {
chosen = p;
*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 __oom_kill_task(task_t *p)
+static void dump_tasks(const struct mem_cgroup *mem)
{
- if (p->pid == 1) {
+ struct task_struct *g, *p;
+
+ printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
+ "name\n");
+ do_each_thread(g, p) {
+ struct mm_struct *mm;
+
+ if (mem && !task_in_mem_cgroup(p, mem))
+ continue;
+ if (!thread_group_leader(p))
+ continue;
+
+ task_lock(p);
+ mm = p->mm;
+ if (!mm) {
+ /*
+ * total_vm and rss sizes do not exist for tasks with no
+ * mm so there's no need to report them; they can't be
+ * oom killed anyway.
+ */
+ task_unlock(p);
+ continue;
+ }
+ printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
+ p->pid, __task_cred(p)->uid, p->tgid, mm->total_vm,
+ get_mm_rss(mm), (int)task_cpu(p), p->signal->oom_adj,
+ p->comm);
+ task_unlock(p);
+ } while_each_thread(g, p);
+}
+
+static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
+ struct mem_cgroup *mem)
+{
+ pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
+ "oom_adj=%d\n",
+ current->comm, gfp_mask, order, current->signal->oom_adj);
+ task_lock(current);
+ cpuset_print_task_mems_allowed(current);
+ task_unlock(current);
+ dump_stack();
+ mem_cgroup_print_oom_info(mem, p);
+ show_mem();
+ if (sysctl_oom_dump_tasks)
+ dump_tasks(mem);
+}
+
+#define K(x) ((x) << (PAGE_SHIFT-10))
+
+/*
+ * 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, int verbose)
+{
+ 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");
+ printk(KERN_WARNING "tried to kill an mm-less task %d (%s)!\n",
+ task_pid_nr(p), p->comm);
task_unlock(p);
return;
}
+
+ if (verbose)
+ printk(KERN_ERR "Killed process %d (%s) "
+ "vsz:%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);
- printk(KERN_ERR "Out of Memory: Killed process %d (%s).\n",
- p->pid, 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 struct mm_struct *oom_kill_task(task_t *p)
+static int oom_kill_task(struct task_struct *p)
{
- struct mm_struct *mm = get_task_mm(p);
- task_t * g, * q;
-
- if (!mm)
- return NULL;
- if (mm == &init_mm) {
- mmput(mm);
- return NULL;
- }
-
- __oom_kill_task(p);
- /*
- * kill all processes that share the ->mm (i.e. all threads),
- * but are in a different thread group
+ /* WARNING: mm may not be dereferenced since we did not obtain its
+ * value from get_task_mm(p). This is OK since all we need to do is
+ * compare mm to q->mm below.
+ *
+ * Furthermore, even if mm contains a non-NULL value, p->mm may
+ * change to NULL at any time since we do not hold task_lock(p).
+ * However, this is of no concern to us.
*/
- do_each_thread(g, q)
- if (q->mm == mm && q->tgid != p->tgid)
- __oom_kill_task(q);
- while_each_thread(g, q);
+ if (!p->mm || p->signal->oom_adj == OOM_DISABLE)
+ return 1;
- return mm;
+ __oom_kill_task(p, 1);
+
+ return 0;
}
-static struct mm_struct *oom_kill_process(struct task_struct *p,
- unsigned long points)
+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 mm_struct *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 (printk_ratelimit())
+ dump_header(p, gfp_mask, order, 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, 0);
+ return 0;
+ }
+
+ 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;
- mm = oom_kill_task(c);
- if (mm)
- return mm;
+ if (mem && !task_in_mem_cgroup(c, mem))
+ continue;
+ if (!oom_kill_task(c))
+ return 0;
}
return oom_kill_task(p);
}
-/**
- * oom_kill - 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)
- * OR try to be smart about which process to kill. Note that we
- * don't have to be perfect here, we just have to be good.
+#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;
+
+ if (sysctl_panic_on_oom == 2)
+ panic("out of memory(memcg). panic_on_oom is selected.\n");
+ 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);
+
+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);
+
+/*
+ * 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.
*/
-void out_of_memory(gfp_t gfp_mask, int order)
+int try_set_zone_oom(struct zonelist *zonelist, gfp_t gfp_mask)
{
- struct mm_struct *mm = NULL;
- task_t * p;
- unsigned long points;
+ 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;
+ }
+ }
- if (printk_ratelimit()) {
- printk("oom-killer: gfp_mask=0x%x, order=%d\n",
- gfp_mask, order);
- dump_stack();
- show_mem();
+ 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);
}
- cpuset_lock();
- read_lock(&tasklist_lock);
+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)
+{
+ struct task_struct *p;
+ unsigned long points;
+
+ if (sysctl_oom_kill_allocating_task)
+ if (!oom_kill_process(current, gfp_mask, order, 0, NULL,
+ "Out of memory (oom_kill_allocating_task)"))
+ return;
retry:
- p = select_bad_process(&points);
+ /*
+ * 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)
- goto out;
+ return;
/* Found nothing?!?! Either we hang forever, or we panic. */
if (!p) {
read_unlock(&tasklist_lock);
- cpuset_unlock();
+ dump_header(NULL, gfp_mask, order, NULL);
panic("Out of memory and no killable processes...\n");
}
- mm = oom_kill_process(p, points);
- if (!mm)
+ 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 (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.
+ */
+ 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)
+ * OR try to be smart about which process to kill. Note that we
+ * don't have to be perfect here, we just have to be good.
+ */
+void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
+ int order, nodemask_t *nodemask)
+{
+ 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 (sysctl_panic_on_oom == 2) {
+ dump_header(NULL, gfp_mask, order, NULL);
+ 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.
+ */
+ constraint = constrained_alloc(zonelist, gfp_mask, nodemask);
+ read_lock(&tasklist_lock);
+
+ switch (constraint) {
+ case CONSTRAINT_MEMORY_POLICY:
+ oom_kill_process(current, gfp_mask, order, 0, NULL,
+ "No available memory (MPOL_BIND)");
+ break;
+
+ case CONSTRAINT_NONE:
+ if (sysctl_panic_on_oom) {
+ dump_header(NULL, gfp_mask, order, NULL);
+ panic("out of memory. panic_on_oom is selected\n");
+ }
+ /* Fall-through */
+ case CONSTRAINT_CPUSET:
+ __out_of_memory(gfp_mask, order);
+ break;
+ }
- out:
read_unlock(&tasklist_lock);
- cpuset_unlock();
- if (mm)
- mmput(mm);
/*
* Give "p" a good chance of killing itself before we
* retry to allocate memory unless "p" is current
*/
if (!test_thread_flag(TIF_MEMDIE))
- schedule_timeout_interruptible(1);
+ schedule_timeout_uninterruptible(1);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff