mm/oom_killer: simplify OOM killer info dump helper

There is only one caller wants to dump the kill victim info, so just let
it call the standalone helper, no need to make the generic info dump
helper take an extra argument for that.

Result of bloat-o-meter:
./scripts/bloat-o-meter ./mm/oom_kill.old.o ./mm/oom_kill.o
add/remove: 0/0 grow/shrink: 1/2 up/down: 131/-142 (-11)
Function                                     old     new   delta
oom_kill_process                             412     543    +131
out_of_memory                               1422    1418      -4
dump_header                                  562     424    -138
Total: Before=21514, After=21503, chg -0.05%

Link: https://lkml.kernel.org/r/20231016113103.86477-1-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/oom_kill.c

@@ -437,7 +437,7 @@ static void dump_tasks(struct oom_control *oc)
 	}
 }
 
-static void dump_oom_summary(struct oom_control *oc, struct task_struct *victim)
+static void dump_oom_victim(struct oom_control *oc, struct task_struct *victim)
 {
 	/* one line summary of the oom killer context. */
 	pr_info("oom-kill:constraint=%s,nodemask=%*pbl",
@@ -449,7 +449,7 @@ static void dump_oom_summary(struct oom_control *oc, struct task_struct *victim)
 		from_kuid(&init_user_ns, task_uid(victim)));
 }
 
-static void dump_header(struct oom_control *oc, struct task_struct *p)
+static void dump_header(struct oom_control *oc)
 {
 	pr_warn("%s invoked oom-killer: gfp_mask=%#x(%pGg), order=%d, oom_score_adj=%hd\n",
 		current->comm, oc->gfp_mask, &oc->gfp_mask, oc->order,
@@ -467,8 +467,6 @@ static void dump_header(struct oom_control *oc, struct task_struct *p)
 	}
 	if (sysctl_oom_dump_tasks)
 		dump_tasks(oc);
-	if (p)
-		dump_oom_summary(oc, p);
 }
 
 /*
@@ -1029,8 +1027,10 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
 	}
 	task_unlock(victim);
 
-	if (__ratelimit(&oom_rs))
-		dump_header(oc, victim);
+	if (__ratelimit(&oom_rs)) {
+		dump_header(oc);
+		dump_oom_victim(oc, victim);
+	}
 
 	/*
 	 * Do we need to kill the entire memory cgroup?
@@ -1072,7 +1072,7 @@ static void check_panic_on_oom(struct oom_control *oc)
 	/* Do not panic for oom kills triggered by sysrq */
 	if (is_sysrq_oom(oc))
 		return;
-	dump_header(oc, NULL);
+	dump_header(oc);
 	panic("Out of memory: %s panic_on_oom is enabled\n",
 		sysctl_panic_on_oom == 2 ? "compulsory" : "system-wide");
 }
@@ -1155,7 +1155,7 @@ bool out_of_memory(struct oom_control *oc)
 	select_bad_process(oc);
 	/* Found nothing?!?! */
 	if (!oc->chosen) {
-		dump_header(oc, NULL);
+		dump_header(oc);
 		pr_warn("Out of memory and no killable processes...\n");
 		/*
 		 * If we got here due to an actual allocation at the