5 files changed, 38 insertions, 14 deletions

diff --git a/include/linux/oom.h b/include/linux/oom.h
index 5e3aa8311c5e..4952fb874ad3 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -40,6 +40,8 @@ enum oom_constraint {
         CONSTRAINT_MEMCG,
 };
 
+extern int test_set_oom_score_adj(int new_val);
+
 extern unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
                         const nodemask_t *nodemask, unsigned long totalpages);
 extern int try_set_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_flags);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index aaf71e08222c..44b8faaac7c0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1753,7 +1753,6 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 #define PF_FROZEN       0x00010000      /* frozen for system suspend */
 #define PF_FSTRANS      0x00020000      /* inside a filesystem transaction */
 #define PF_KSWAPD       0x00040000      /* I am kswapd */
-#define PF_OOM_ORIGIN   0x00080000      /* Allocating much memory to others */
 #define PF_LESS_THROTTLE 0x00100000     /* Throttle me less: I clean memory */
 #define PF_KTHREAD      0x00200000      /* I am a kernel thread */
 #define PF_RANDOMIZE    0x00400000      /* randomize virtual address space */
diff --git a/mm/ksm.c b/mm/ksm.c
index 942dfc73a2ff..d708b3ef2260 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -35,6 +35,7 @@
 #include <linux/ksm.h>
 #include <linux/hash.h>
 #include <linux/freezer.h>
+#include <linux/oom.h>
 
 #include <asm/tlbflush.h>
 #include "internal.h"
@@ -1894,9 +1895,11 @@ static ssize_t run_store(struct kobject *kobj, struct kobj_attribute *attr,
         if (ksm_run != flags) {
                 ksm_run = flags;
                 if (flags & KSM_RUN_UNMERGE) {
-                        current->flags |= PF_OOM_ORIGIN;
+                        int oom_score_adj;
+
+                        oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
                         err = unmerge_and_remove_all_rmap_items();
-                        current->flags &= ~PF_OOM_ORIGIN;
+                        test_set_oom_score_adj(oom_score_adj);
                         if (err) {
                                 ksm_run = KSM_RUN_STOP;
                                 count = err;
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index f52e85c80e8d..e4b0991ca351 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -38,6 +38,33 @@ int sysctl_oom_kill_allocating_task;
 int sysctl_oom_dump_tasks = 1;
 static DEFINE_SPINLOCK(zone_scan_lock);
 
+/**
+ * test_set_oom_score_adj() - set current's oom_score_adj and return old value
+ * @new_val: new oom_score_adj value
+ *
+ * Sets the oom_score_adj value for current to @new_val with proper
+ * synchronization and returns the old value.  Usually used to temporarily
+ * set a value, save the old value in the caller, and then reinstate it later.
+ */
+int test_set_oom_score_adj(int new_val)
+{
+        struct sighand_struct *sighand = current->sighand;
+        int old_val;
+
+        spin_lock_irq(&sighand->siglock);
+        old_val = current->signal->oom_score_adj;
+        if (new_val != old_val) {
+                if (new_val == OOM_SCORE_ADJ_MIN)
+                        atomic_inc(&current->mm->oom_disable_count);
+                else if (old_val == OOM_SCORE_ADJ_MIN)
+                        atomic_dec(&current->mm->oom_disable_count);
+                current->signal->oom_score_adj = new_val;
+        }
+        spin_unlock_irq(&sighand->siglock);
+
+        return old_val;
+}
+
 #ifdef CONFIG_NUMA
 /**
  * has_intersects_mems_allowed() - check task eligiblity for kill
@@ -155,15 +182,6 @@ unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
         }
 
         /*
-         * When the PF_OOM_ORIGIN bit is set, it indicates the task should have
-         * priority for oom killing.
-         */
-        if (p->flags & PF_OOM_ORIGIN) {
-                task_unlock(p);
-                return 1000;
-        }
-
-        /*
          * The memory controller may have a limit of 0 bytes, so avoid a divide
          * by zero, if necessary.
          */
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 8c6b3ce38f09..d537d29e9b7b 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -31,6 +31,7 @@
 #include <linux/syscalls.h>
 #include <linux/memcontrol.h>
 #include <linux/poll.h>
+#include <linux/oom.h>
 
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
@@ -1555,6 +1556,7 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
         struct address_space *mapping;
         struct inode *inode;
         char *pathname;
+        int oom_score_adj;
         int i, type, prev;
         int err;
 
@@ -1613,9 +1615,9 @@ SYSCALL_DEFINE1(swapoff, const char __user *, specialfile)
         p->flags &= ~SWP_WRITEOK;
         spin_unlock(&swap_lock);
 
-        current->flags |= PF_OOM_ORIGIN;
+        oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
         err = try_to_unuse(type);
-        current->flags &= ~PF_OOM_ORIGIN;
+        test_set_oom_score_adj(oom_score_adj);
 
         if (err) {
                 /*