Index: sys/amd64/amd64/pmap.c
===================================================================
--- sys/amd64/amd64/pmap.c
+++ sys/amd64/amd64/pmap.c
@@ -436,7 +436,7 @@
 static SYSCTL_NODE(_vm, OID_AUTO, pmap, CTLFLAG_RD | CTLFLAG_MPSAFE, 0,
     "VM/pmap parameters");
 
-static int pg_ps_enabled = 1;
+static int __read_frequently pg_ps_enabled = 1;
 SYSCTL_INT(_vm_pmap, OID_AUTO, pg_ps_enabled, CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
     &pg_ps_enabled, 0, "Are large page mappings enabled?");
 
@@ -1318,7 +1318,7 @@
 static vm_page_t pmap_large_map_getptp_unlocked(void);
 static vm_paddr_t pmap_large_map_kextract(vm_offset_t va);
 #if VM_NRESERVLEVEL > 0
-static void pmap_promote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va,
+static bool pmap_promote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va,
     vm_page_t mpte, struct rwlock **lockp);
 #endif
 static boolean_t pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t sva,
@@ -6856,7 +6856,7 @@
  * aligned, contiguous physical memory and (2) the 4KB page mappings must have
  * identical characteristics. 
  */
-static void
+static bool
 pmap_promote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va, vm_page_t mpte,
     struct rwlock **lockp)
 {
@@ -6865,6 +6865,10 @@
 	pt_entry_t allpte_PG_A, PG_A, PG_G, PG_M, PG_PKU_MASK, PG_RW, PG_V;
 	int PG_PTE_CACHE;
 
+	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
+	if (!pmap_ps_enabled(pmap))
+		return (false);
+
 	PG_A = pmap_accessed_bit(pmap);
 	PG_G = pmap_global_bit(pmap);
 	PG_M = pmap_modified_bit(pmap);
@@ -6873,8 +6877,6 @@
 	PG_PKU_MASK = pmap_pku_mask_bit(pmap);
 	PG_PTE_CACHE = pmap_cache_mask(pmap, 0);
 
-	PMAP_LOCK_ASSERT(pmap, MA_OWNED);
-
 	/*
 	 * Examine the first PTE in the specified PTP.  Abort if this PTE is
 	 * ineligible for promotion due to hardware errata, invalid, or does
@@ -6883,12 +6885,12 @@
 	firstpte = (pt_entry_t *)PHYS_TO_DMAP(*pde & PG_FRAME);
 	newpde = *firstpte;
 	if (!pmap_allow_2m_x_page(pmap, pmap_pde_ept_executable(pmap, newpde)))
-		return;
+		return (false);
 	if ((newpde & ((PG_FRAME & PDRMASK) | PG_V)) != PG_V) {
 		counter_u64_add(pmap_pde_p_failures, 1);
 		CTR2(KTR_PMAP, "pmap_promote_pde: failure for va %#lx"
 		    " in pmap %p", va, pmap);
-		return;
+		return (false);
 	}
 
 	/*
@@ -6933,7 +6935,7 @@
 			counter_u64_add(pmap_pde_p_failures, 1);
 			CTR2(KTR_PMAP, "pmap_promote_pde: failure for va %#lx"
 			    " in pmap %p", va, pmap);
-			return;
+			return (false);
 		}
 setpte:
 		if ((oldpte & (PG_M | PG_RW)) == PG_RW) {
@@ -6952,7 +6954,7 @@
 			counter_u64_add(pmap_pde_p_failures, 1);
 			CTR2(KTR_PMAP, "pmap_promote_pde: failure for va %#lx"
 			    " in pmap %p", va, pmap);
-			return;
+			return (false);
 		}
 		allpte_PG_A &= oldpte;
 		pa -= PAGE_SIZE;
@@ -6993,7 +6995,7 @@
 		CTR2(KTR_PMAP,
 		    "pmap_promote_pde: failure for va %#lx in pmap %p", va,
 		    pmap);
-		return;
+		return (false);
 	}
 
 	/*
@@ -7018,6 +7020,7 @@
 	counter_u64_add(pmap_pde_promotions, 1);
 	CTR2(KTR_PMAP, "pmap_promote_pde: success for va %#lx"
 	    " in pmap %p", va, pmap);
+	return (true);
 }
 #endif /* VM_NRESERVLEVEL > 0 */
 
@@ -7391,10 +7394,9 @@
 	 * populated, then attempt promotion.
 	 */
 	if ((mpte == NULL || mpte->ref_count == NPTEPG) &&
-	    pmap_ps_enabled(pmap) &&
 	    (m->flags & PG_FICTITIOUS) == 0 &&
 	    vm_reserv_level_iffullpop(m) == 0)
-		pmap_promote_pde(pmap, pde, va, mpte, &lock);
+		(void)pmap_promote_pde(pmap, pde, va, mpte, &lock);
 #endif
 
 	rv = KERN_SUCCESS;
@@ -7782,18 +7784,17 @@
 	 * attempt promotion.
 	 */
 	if ((mpte == NULL || mpte->ref_count == NPTEPG) &&
-	    pmap_ps_enabled(pmap) &&
 	    (m->flags & PG_FICTITIOUS) == 0 &&
 	    vm_reserv_level_iffullpop(m) == 0) {
 		if (pde == NULL)
 			pde = pmap_pde(pmap, va);
-		pmap_promote_pde(pmap, pde, va, mpte, lockp);
 
 		/*
 		 * If promotion succeeds, then the next call to this function
 		 * should not be given the unmapped PTP as a hint.
 		 */
-		mpte = NULL;
+		if (pmap_promote_pde(pmap, pde, va, mpte, lockp))
+			mpte = NULL;
 	}
 #endif
 
@@ -10359,10 +10360,9 @@
 	m = PHYS_TO_VM_PAGE(*pte & PG_FRAME);
 
 	if ((mpte == NULL || mpte->ref_count == NPTEPG) &&
-	    pmap_ps_enabled(pmap) &&
 	    (m->flags & PG_FICTITIOUS) == 0 &&
-	    vm_reserv_level_iffullpop(m) == 0) {
-		pmap_promote_pde(pmap, pde, va, mpte, &lock);
+	    vm_reserv_level_iffullpop(m) == 0 &&
+	    pmap_promote_pde(pmap, pde, va, mpte, &lock)) {
 #ifdef INVARIANTS
 		atomic_add_long(&ad_emulation_superpage_promotions, 1);
 #endif