---

yaml
---
r: 207212
b: refs/heads/master
c: 6f48d0e
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 5e9d834a0e0c0485dfa487281ab9650fc37a3bb5
+refs/heads/master: 6f48d0ebd907ae419387f27b602ee98870cfa7bb

trunk/include/linux/mempolicy.h

@@ -210,6 +210,8 @@ extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
 				unsigned long addr, gfp_t gfp_flags,
 				struct mempolicy **mpol, nodemask_t **nodemask);
 extern bool init_nodemask_of_mempolicy(nodemask_t *mask);
+extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
+				const nodemask_t *mask);
 extern unsigned slab_node(struct mempolicy *policy);
 
 extern enum zone_type policy_zone;
@@ -338,7 +340,16 @@ static inline struct zonelist *huge_zonelist(struct vm_area_struct *vma,
 	return node_zonelist(0, gfp_flags);
 }
 
-static inline bool init_nodemask_of_mempolicy(nodemask_t *m) { return false; }
+static inline bool init_nodemask_of_mempolicy(nodemask_t *m)
+{
+	return false;
+}
+
+static inline bool mempolicy_nodemask_intersects(struct task_struct *tsk,
+			const nodemask_t *mask)
+{
+	return false;
+}
 
 static inline int do_migrate_pages(struct mm_struct *mm,
 			const nodemask_t *from_nodes,

trunk/mm/mempolicy.c

@@ -1712,6 +1712,50 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask)
 }
 #endif
 
+/*
+ * mempolicy_nodemask_intersects
+ *
+ * If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
+ * policy.  Otherwise, check for intersection between mask and the policy
+ * nodemask for 'bind' or 'interleave' policy.  For 'perferred' or 'local'
+ * policy, always return true since it may allocate elsewhere on fallback.
+ *
+ * Takes task_lock(tsk) to prevent freeing of its mempolicy.
+ */
+bool mempolicy_nodemask_intersects(struct task_struct *tsk,
+					const nodemask_t *mask)
+{
+	struct mempolicy *mempolicy;
+	bool ret = true;
+
+	if (!mask)
+		return ret;
+	task_lock(tsk);
+	mempolicy = tsk->mempolicy;
+	if (!mempolicy)
+		goto out;
+
+	switch (mempolicy->mode) {
+	case MPOL_PREFERRED:
+		/*
+		 * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
+		 * allocate from, they may fallback to other nodes when oom.
+		 * Thus, it's possible for tsk to have allocated memory from
+		 * nodes in mask.
+		 */
+		break;
+	case MPOL_BIND:
+	case MPOL_INTERLEAVE:
+		ret = nodes_intersects(mempolicy->v.nodes, *mask);
+		break;
+	default:
+		BUG();
+	}
+out:
+	task_unlock(tsk);
+	return ret;
+}
+
 /* Allocate a page in interleaved policy.
    Own path because it needs to do special accounting. */
 static struct page *alloc_page_interleave(gfp_t gfp, unsigned order,

trunk/mm/oom_kill.c

@@ -27,6 +27,7 @@
 #include <linux/module.h>
 #include <linux/notifier.h>
 #include <linux/memcontrol.h>
+#include <linux/mempolicy.h>
 #include <linux/security.h>
 
 int sysctl_panic_on_oom;
@@ -35,23 +36,57 @@ int sysctl_oom_dump_tasks;
 static DEFINE_SPINLOCK(zone_scan_lock);
 /* #define DEBUG */
 
-/*
- * Is all threads of the target process nodes overlap ours?
+#ifdef CONFIG_NUMA
+/**
+ * has_intersects_mems_allowed() - check task eligiblity for kill
+ * @tsk: task struct of which task to consider
+ * @mask: nodemask passed to page allocator for mempolicy ooms
+ *
+ * Task eligibility is determined by whether or not a candidate task, @tsk,
+ * shares the same mempolicy nodes as current if it is bound by such a policy
+ * and whether or not it has the same set of allowed cpuset nodes.
  */
-static int has_intersects_mems_allowed(struct task_struct *tsk)
+static bool has_intersects_mems_allowed(struct task_struct *tsk,
+					const nodemask_t *mask)
 {
-	struct task_struct *t;
+	struct task_struct *start = tsk;
 
-	t = tsk;
 	do {
-		if (cpuset_mems_allowed_intersects(current, t))
-			return 1;
-		t = next_thread(t);
-	} while (t != tsk);
-
-	return 0;
+		if (mask) {
+			/*
+			 * If this is a mempolicy constrained oom, tsk's
+			 * cpuset is irrelevant.  Only return true if its
+			 * mempolicy intersects current, otherwise it may be
+			 * needlessly killed.
+			 */
+			if (mempolicy_nodemask_intersects(tsk, mask))
+				return true;
+		} else {
+			/*
+			 * This is not a mempolicy constrained oom, so only
+			 * check the mems of tsk's cpuset.
+			 */
+			if (cpuset_mems_allowed_intersects(current, tsk))
+				return true;
+		}
+		tsk = next_thread(tsk);
+	} while (tsk != start);
+	return false;
+}
+#else
+static bool has_intersects_mems_allowed(struct task_struct *tsk,
+					const nodemask_t *mask)
+{
+	return true;
 }
+#endif /* CONFIG_NUMA */
 
+/*
+ * The process p may have detached its own ->mm while exiting or through
+ * use_mm(), but one or more of its subthreads may still have a valid
+ * pointer.  Return p, or any of its subthreads with a valid ->mm, with
+ * task_lock() held.
+ */
 static struct task_struct *find_lock_task_mm(struct task_struct *p)
 {
 	struct task_struct *t = p;
@@ -106,10 +141,6 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
 	 * The memory size of the process is the basis for the badness.
 	 */
 	points = p->mm->total_vm;
-
-	/*
-	 * After this unlock we can no longer dereference local variable `mm'
-	 */
 	task_unlock(p);
 
 	/*
@@ -253,7 +284,8 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
  * (not docbooked, we don't want this one cluttering up the manual)
  */
 static struct task_struct *select_bad_process(unsigned long *ppoints,
-						struct mem_cgroup *mem)
+		struct mem_cgroup *mem, enum oom_constraint constraint,
+		const nodemask_t *mask)
 {
 	struct task_struct *p;
 	struct task_struct *chosen = NULL;
@@ -269,7 +301,9 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
 			continue;
 		if (mem && !task_in_mem_cgroup(p, mem))
 			continue;
-		if (!has_intersects_mems_allowed(p))
+		if (!has_intersects_mems_allowed(p,
+				constraint == CONSTRAINT_MEMORY_POLICY ? mask :
+									 NULL))
 			continue;
 
 		/*
@@ -497,7 +531,7 @@ void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
 		panic("out of memory(memcg). panic_on_oom is selected.\n");
 	read_lock(&tasklist_lock);
 retry:
-	p = select_bad_process(&points, mem);
+	p = select_bad_process(&points, mem, CONSTRAINT_NONE, NULL);
 	if (!p || PTR_ERR(p) == -1UL)
 		goto out;
 
@@ -576,7 +610,8 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask)
 /*
  * Must be called with tasklist_lock held for read.
  */
-static void __out_of_memory(gfp_t gfp_mask, int order)
+static void __out_of_memory(gfp_t gfp_mask, int order,
+			enum oom_constraint constraint, const nodemask_t *mask)
 {
 	struct task_struct *p;
 	unsigned long points;
@@ -590,7 +625,7 @@ static void __out_of_memory(gfp_t gfp_mask, int order)
 	 * Rambo mode: Shoot down a process and hope it solves whatever
 	 * issues we may have.
 	 */
-	p = select_bad_process(&points, NULL);
+	p = select_bad_process(&points, NULL, constraint, mask);
 
 	if (PTR_ERR(p) == -1UL)
 		return;
@@ -624,7 +659,8 @@ void pagefault_out_of_memory(void)
 		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 */
+	/* unknown gfp_mask and order */
+	__out_of_memory(0, 0, CONSTRAINT_NONE, NULL);
 	read_unlock(&tasklist_lock);
 
 	/*
@@ -640,6 +676,7 @@ void pagefault_out_of_memory(void)
  * @zonelist: zonelist pointer
  * @gfp_mask: memory allocation flags
  * @order: amount of memory being requested as a power of 2
+ * @nodemask: nodemask passed to page allocator
  *
  * If we run out of memory, we have the choice between either
  * killing a random task (bad), letting the system crash (worse)
@@ -678,24 +715,19 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
 	 */
 	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) {
+	if (unlikely(sysctl_panic_on_oom)) {
+		/*
+		 * panic_on_oom only affects CONSTRAINT_NONE, the kernel
+		 * should not panic for cpuset or mempolicy induced memory
+		 * failures.
+		 */
+		if (constraint == CONSTRAINT_NONE) {
 			dump_header(NULL, gfp_mask, order, NULL);
-			panic("out of memory. panic_on_oom is selected\n");
+			read_unlock(&tasklist_lock);
+			panic("Out of memory: panic_on_oom is enabled\n");
 		}
-		/* Fall-through */
-	case CONSTRAINT_CPUSET:
-		__out_of_memory(gfp_mask, order);
-		break;
 	}
-
+	__out_of_memory(gfp_mask, order, constraint, nodemask);
 	read_unlock(&tasklist_lock);
 
 	/*