mm, oom: fold oom_kill_task() into oom_kill_process()

oom_kill_task() has a single caller, so fold it into its parent function,
oom_kill_process().  Slightly reduces the number of lines in the oom
killer.

Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 38 insertions, 47 deletions

diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index a26695fe8833..d402b2c1040e 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -434,52 +434,6 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
 }
 
 #define K(x) ((x) << (PAGE_SHIFT-10))
-static void oom_kill_task(struct task_struct *p)
-{
-        struct task_struct *q;
-        struct mm_struct *mm;
-
-        p = find_lock_task_mm(p);
-        if (!p)
-                return;
-
-        /* mm cannot be safely dereferenced after task_unlock(p) */
-        mm = p->mm;
-
-        pr_err("Killed process %d (%s) total-vm:%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);
-
-        /*
-         * Kill all user processes sharing p->mm in other thread groups, if any.
-         * They don't get access to memory reserves or a higher scheduler
-         * priority, though, to avoid depletion of all memory or task
-         * starvation.  This prevents mm->mmap_sem livelock when an oom killed
-         * task cannot exit because it requires the semaphore and its contended
-         * by another thread trying to allocate memory itself.  That thread will
-         * now get access to memory reserves since it has a pending fatal
-         * signal.
-         */
-        for_each_process(q)
-                if (q->mm == mm && !same_thread_group(q, p) &&
-                    !(q->flags & PF_KTHREAD)) {
-                        if (q->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
-                                continue;
-
-                        task_lock(q);   /* Protect ->comm from prctl() */
-                        pr_err("Kill process %d (%s) sharing same memory\n",
-                                task_pid_nr(q), q->comm);
-                        task_unlock(q);
-                        force_sig(SIGKILL, q);
-                }
-
-        set_tsk_thread_flag(p, TIF_MEMDIE);
-        force_sig(SIGKILL, p);
-}
-#undef K
-
 static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
                              unsigned int points, unsigned long totalpages,
                              struct mem_cgroup *memcg, nodemask_t *nodemask,
@@ -488,6 +442,7 @@ static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
         struct task_struct *victim = p;
         struct task_struct *child;
         struct task_struct *t = p;
+        struct mm_struct *mm;
         unsigned int victim_points = 0;
 
         if (printk_ratelimit())
@@ -531,8 +486,44 @@ static void oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
                 }
         } while_each_thread(p, t);
 
-        oom_kill_task(victim);
+        victim = find_lock_task_mm(victim);
+        if (!victim)
+                return;
+
+        /* mm cannot safely be dereferenced after task_unlock(victim) */
+        mm = victim->mm;
+        pr_err("Killed process %d (%s) total-vm:%lukB, anon-rss:%lukB, file-rss:%lukB\n",
+                task_pid_nr(victim), victim->comm, K(victim->mm->total_vm),
+                K(get_mm_counter(victim->mm, MM_ANONPAGES)),
+                K(get_mm_counter(victim->mm, MM_FILEPAGES)));
+        task_unlock(victim);
+
+        /*
+         * Kill all user processes sharing victim->mm in other thread groups, if
+         * any.  They don't get access to memory reserves, though, to avoid
+         * depletion of all memory.  This prevents mm->mmap_sem livelock when an
+         * oom killed thread cannot exit because it requires the semaphore and
+         * its contended by another thread trying to allocate memory itself.
+         * That thread will now get access to memory reserves since it has a
+         * pending fatal signal.
+         */
+        for_each_process(p)
+                if (p->mm == mm && !same_thread_group(p, victim) &&
+                    !(p->flags & PF_KTHREAD)) {
+                        if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN)
+                                continue;
+
+                        task_lock(p);   /* Protect ->comm from prctl() */
+                        pr_err("Kill process %d (%s) sharing same memory\n",
+                                task_pid_nr(p), p->comm);
+                        task_unlock(p);
+                        force_sig(SIGKILL, p);
+                }
+
+        set_tsk_thread_flag(victim, TIF_MEMDIE);
+        force_sig(SIGKILL, victim);
 }
+#undef K
 
 /*
  * Determines whether the kernel must panic because of the panic_on_oom sysctl.