1 files changed, 91 insertions, 32 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index b05ab8f2a562..8123fad5a485 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -58,15 +58,17 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
 
         /*
          * Processes which fork a lot of child processes are likely
-         * a good choice. We add the vmsize of the children if they
+         * a good choice. We add half the vmsize of the children if they
          * have an own mm. This prevents forking servers to flood the
-         * machine with an endless amount of children
+         * machine with an endless amount of children. In case a single
+         * 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;
+                        points += chld->mm->total_vm/2 + 1;
         }
 
         /*
@@ -131,17 +133,47 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
 }
 
 /*
+ * 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)
+{
+#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);
+                else
+                        return CONSTRAINT_CPUSET;
+
+        if (!nodes_empty(nodes))
+                return CONSTRAINT_MEMORY_POLICY;
+#endif
+
+        return CONSTRAINT_NONE;
+}
+
+/*
  * 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(void)
+static struct task_struct *select_bad_process(unsigned long *ppoints)
 {
-        unsigned long maxpoints = 0;
         struct task_struct *g, *p;
         struct task_struct *chosen = NULL;
         struct timespec uptime;
+        *ppoints = 0;
 
         do_posix_clock_monotonic_gettime(&uptime);
         do_each_thread(g, p) {
@@ -169,9 +201,9 @@ static struct task_struct * select_bad_process(void)
                         return p;
 
                 points = badness(p, uptime.tv_sec);
-                if (points > maxpoints || !chosen) {
+                if (points > *ppoints || !chosen) {
                         chosen = p;
-                        maxpoints = points;
+                        *ppoints = points;
                 }
         } while_each_thread(g, p);
         return chosen;
@@ -182,7 +214,7 @@ static struct task_struct * select_bad_process(void)
  * 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)
+static void __oom_kill_task(task_t *p, const char *message)
 {
         if (p->pid == 1) {
                 WARN_ON(1);
@@ -198,8 +230,8 @@ static void __oom_kill_task(task_t *p)
                 return;
         }
         task_unlock(p);
-        printk(KERN_ERR "Out of Memory: Killed process %d (%s).\n",
-                                                        p->pid, p->comm);
+        printk(KERN_ERR "%s: Killed process %d (%s).\n",
+                                message, p->pid, p->comm);
 
         /*
          * We give our sacrificial lamb high priority and access to
@@ -212,7 +244,7 @@ static void __oom_kill_task(task_t *p)
         force_sig(SIGKILL, p);
 }
 
-static struct mm_struct *oom_kill_task(task_t *p)
+static struct mm_struct *oom_kill_task(task_t *p, const char *message)
 {
         struct mm_struct *mm = get_task_mm(p);
         task_t * g, * q;
@@ -224,35 +256,38 @@ static struct mm_struct *oom_kill_task(task_t *p)
                 return NULL;
         }
 
-        __oom_kill_task(p);
+        __oom_kill_task(p, message);
         /*
          * kill all processes that share the ->mm (i.e. all threads),
          * but are in a different thread group
          */
         do_each_thread(g, q)
                 if (q->mm == mm && q->tgid != p->tgid)
-                        __oom_kill_task(q);
+                        __oom_kill_task(q, message);
         while_each_thread(g, q);
 
         return mm;
 }
 
-static struct mm_struct *oom_kill_process(struct task_struct *p)
+static struct mm_struct *oom_kill_process(struct task_struct *p,
+                                unsigned long points, 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);
         /* 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;
-                mm = oom_kill_task(c);
+                mm = oom_kill_task(c, message);
                 if (mm)
                         return mm;
         }
-        return oom_kill_task(p);
+        return oom_kill_task(p, message);
 }
 
 /**
@@ -263,10 +298,11 @@ static struct mm_struct *oom_kill_process(struct task_struct *p)
  * 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(gfp_t gfp_mask, int order)
+void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
 {
         struct mm_struct *mm = NULL;
-        task_t * p;
+        task_t *p;
+        unsigned long points;
 
         if (printk_ratelimit()) {
                 printk("oom-killer: gfp_mask=0x%x, order=%d\n",
@@ -277,25 +313,48 @@ void out_of_memory(gfp_t gfp_mask, int order)
 
         cpuset_lock();
         read_lock(&tasklist_lock);
+
+        /*
+         * Check if there were limitations on the allocation (only relevant for
+         * NUMA) that may require different handling.
+         */
+        switch (constrained_alloc(zonelist, gfp_mask)) {
+        case CONSTRAINT_MEMORY_POLICY:
+                mm = oom_kill_process(current, points,
+                                "No available memory (MPOL_BIND)");
+                break;
+
+        case CONSTRAINT_CPUSET:
+                mm = oom_kill_process(current, points,
+                                "No available memory in cpuset");
+                break;
+
+        case CONSTRAINT_NONE:
 retry:
-        p = select_bad_process();
+                /*
+                 * 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;
+                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");
-        }
+                /* 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");
+                }
 
-        mm = oom_kill_process(p);
-        if (!mm)
-                goto retry;
+                mm = oom_kill_process(p, points, "Out of memory");
+                if (!mm)
+                        goto retry;
+
+                break;
+        }
 
- out:
-        read_unlock(&tasklist_lock);
+out:
         cpuset_unlock();
         if (mm)
                 mmput(mm);