--- zzzz-none-000/linux-3.10.107/arch/arm64/mm/pgd.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/arm64/mm/pgd.c	2021-02-04 17:41:59.000000000 +0000
@@ -28,21 +28,14 @@
 
 #include "mm.h"
 
-#define PGD_SIZE	(PTRS_PER_PGD * sizeof(pgd_t))
+static struct kmem_cache *pgd_cache;
 
 pgd_t *pgd_alloc(struct mm_struct *mm)
 {
-	pgd_t *new_pgd;
-
 	if (PGD_SIZE == PAGE_SIZE)
-		new_pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
+		return (pgd_t *)__get_free_page(PGALLOC_GFP);
 	else
-		new_pgd = kzalloc(PGD_SIZE, GFP_KERNEL);
-
-	if (!new_pgd)
-		return NULL;
-
-	return new_pgd;
+		return kmem_cache_alloc(pgd_cache, PGALLOC_GFP);
 }
 
 void pgd_free(struct mm_struct *mm, pgd_t *pgd)
@@ -50,5 +43,17 @@
 	if (PGD_SIZE == PAGE_SIZE)
 		free_page((unsigned long)pgd);
 	else
-		kfree(pgd);
+		kmem_cache_free(pgd_cache, pgd);
+}
+
+static int __init pgd_cache_init(void)
+{
+	/*
+	 * Naturally aligned pgds required by the architecture.
+	 */
+	if (PGD_SIZE != PAGE_SIZE)
+		pgd_cache = kmem_cache_create("pgd_cache", PGD_SIZE, PGD_SIZE,
+					      SLAB_PANIC, NULL);
+	return 0;
 }
+core_initcall(pgd_cache_init);