simple_lmk: Update adj targeting for Android 10

Android 10 changed its adj assignments. Update Simple LMK to use the
new adjs, which also requires looking at each pair of adjs as a range.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>

drivers/android/simple_lmk.c

@@ -29,23 +29,21 @@ struct victim_info {
 };
 
 /* Pulled from the Android framework. Lower adj means higher priority. */
-static const short adj_prio[] = {
-	906, /* CACHED_APP_MAX_ADJ */
-	905, /* Cached app */
-	904, /* Cached app */
-	903, /* Cached app */
-	902, /* Cached app */
-	901, /* Cached app */
-	900, /* CACHED_APP_MIN_ADJ */
-	800, /* SERVICE_B_ADJ */
-	700, /* PREVIOUS_APP_ADJ */
-	600, /* HOME_APP_ADJ */
-	500, /* SERVICE_ADJ */
-	400, /* HEAVY_WEIGHT_APP_ADJ */
-	300, /* BACKUP_APP_ADJ */
-	200, /* PERCEPTIBLE_APP_ADJ */
-	100, /* VISIBLE_APP_ADJ */
-	0    /* FOREGROUND_APP_ADJ */
+static const short adjs[] = {
+	1000, /* CACHED_APP_MAX_ADJ + 1 */
+	950,  /* CACHED_APP_LMK_FIRST_ADJ */
+	900,  /* CACHED_APP_MIN_ADJ */
+	800,  /* SERVICE_B_ADJ */
+	700,  /* PREVIOUS_APP_ADJ */
+	600,  /* HOME_APP_ADJ */
+	500,  /* SERVICE_ADJ */
+	400,  /* HEAVY_WEIGHT_APP_ADJ */
+	300,  /* BACKUP_APP_ADJ */
+	250,  /* PERCEPTIBLE_LOW_APP_ADJ */
+	200,  /* PERCEPTIBLE_APP_ADJ */
+	100,  /* VISIBLE_APP_ADJ */
+	50,   /* PERCEPTIBLE_RECENT_FOREGROUND_APP_ADJ */
+	0     /* FOREGROUND_APP_ADJ */
 };
 
 static struct victim_info victims[MAX_VICTIMS];
@@ -87,7 +85,8 @@ static unsigned long get_total_mm_pages(struct mm_struct *mm)
 	return pages;
 }
 
-static unsigned long find_victims(int *vindex, short target_adj)
+static unsigned long find_victims(int *vindex, short target_adj_min,
+				  short target_adj_max)
 {
 	unsigned long pages_found = 0;
 	int old_vindex = *vindex;
@@ -96,6 +95,7 @@ static unsigned long find_victims(int *vindex, short target_adj)
 	for_each_process(tsk) {
 		struct signal_struct *sig;
 		struct task_struct *vtsk;
+		short adj;
 
 		/*
 		 * Search for suitable tasks with the targeted importance (adj).
@@ -107,7 +107,8 @@ static unsigned long find_victims(int *vindex, short target_adj)
 		 * trying to lock a task that we locked earlier.
 		 */
 		sig = tsk->signal;
-		if (READ_ONCE(sig->oom_score_adj) != target_adj ||
+		adj = READ_ONCE(sig->oom_score_adj);
+		if (adj < target_adj_min || adj > target_adj_max - 1 ||
 		    sig->flags & (SIGNAL_GROUP_EXIT | SIGNAL_GROUP_COREDUMP) ||
 		    (thread_group_empty(tsk) && tsk->flags & PF_EXITING) ||
 		    vtsk_is_duplicate(*vindex, tsk))
@@ -177,8 +178,8 @@ static void scan_and_kill(unsigned long pages_needed)
 	 * is guaranteed to be up to date.
 	 */
 	read_lock(&tasklist_lock);
-	for (i = 0; i < ARRAY_SIZE(adj_prio); i++) {
-		pages_found += find_victims(&nr_victims, adj_prio[i]);
+	for (i = 1; i < ARRAY_SIZE(adjs); i++) {
+		pages_found += find_victims(&nr_victims, adjs[i], adjs[i - 1]);
 		if (pages_found >= pages_needed || nr_victims == MAX_VICTIMS)
 			break;
 	}