Fix VM_MAYEXEC calculation

[pandora-kernel.git] / mm / oom_kill.c

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index bada3d0..20f41b0 100644 (file)
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -204,15 +204,29 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
        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_init(p))
                        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.
@@ -221,21 +235,16 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
                 * 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;
 
@@ -245,6 +254,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
                        *ppoints = points;
                }
        } while_each_thread(g, p);
+
        return chosen;
 }
 
@@ -255,20 +265,17 @@ static struct task_struct *select_bad_process(unsigned long *ppoints)
  */
 static void __oom_kill_task(struct task_struct *p, const char *message)
 {
-       if (p->pid == 1) {
+       if (is_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",
@@ -302,7 +309,7 @@ static int oom_kill_task(struct task_struct *p, const char *message)
         * However, this is of no concern to us.
         */
 
-       if (mm == NULL || mm == &init_mm)
+       if (mm == NULL)
                return 1;
 
        __oom_kill_task(p, message);