From 9eab548476d925231c8b2d67643f716dc37823fb Mon Sep 17 00:00:00 2001
From: Konstantin Belousov <kib@FreeBSD.org>
Date: Tue, 17 Sep 2013 07:35:26 +0000
Subject: [PATCH] PG_SLAB no longer serves a useful purpose, since m->object is
 no longer abused to store pointer to slab. Remove it.

Reviewed by:    alc
Sponsored by:   The FreeBSD Foundation
Approved by:	re (hrs)
---
 sys/vm/uma_int.h   | 9 +--------
 sys/vm/vm_page.c   | 6 ++----
 sys/vm/vm_page.h   | 1 -
 sys/vm/vm_reserv.c | 3 +--
 4 files changed, 4 insertions(+), 15 deletions(-)

diff --git a/sys/vm/uma_int.h b/sys/vm/uma_int.h
index ec88e58e679e..00e8519e07c7 100644
--- a/sys/vm/uma_int.h
+++ b/sys/vm/uma_int.h
@@ -404,15 +404,9 @@ static __inline uma_slab_t
 vtoslab(vm_offset_t va)
 {
 	vm_page_t p;
-	uma_slab_t slab;
 
 	p = PHYS_TO_VM_PAGE(pmap_kextract(va));
-	slab = (uma_slab_t )p->plinks.s.pv;
-
-	if (p->flags & PG_SLAB)
-		return (slab);
-	else
-		return (NULL);
+	return ((uma_slab_t)p->plinks.s.pv);
 }
 
 static __inline void
@@ -422,7 +416,6 @@ vsetslab(vm_offset_t va, uma_slab_t slab)
 
 	p = PHYS_TO_VM_PAGE(pmap_kextract(va));
 	p->plinks.s.pv = slab;
-	p->flags |= PG_SLAB;
 }
 
 /*
diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index ac28bc4b6384..696f4eebfeff 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -968,8 +968,7 @@ vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex,
 	KASSERT(m->object == NULL,
 	    ("vm_page_insert_after: page already inserted"));
 	if (mpred != NULL) {
-		KASSERT(mpred->object == object ||
-		    (mpred->flags & PG_SLAB) != 0,
+		KASSERT(mpred->object == object,
 		    ("vm_page_insert_after: object doesn't contain mpred"));
 		KASSERT(mpred->pindex < pindex,
 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
@@ -1019,8 +1018,7 @@ vm_page_insert_radixdone(vm_page_t m, vm_object_t object, vm_page_t mpred)
 	KASSERT(object != NULL && m->object == object,
 	    ("vm_page_insert_radixdone: page %p has inconsistent object", m));
 	if (mpred != NULL) {
-		KASSERT(mpred->object == object ||
-		    (mpred->flags & PG_SLAB) != 0,
+		KASSERT(mpred->object == object,
 		    ("vm_page_insert_after: object doesn't contain mpred"));
 		KASSERT(mpred->pindex < m->pindex,
 		    ("vm_page_insert_after: mpred doesn't precede pindex"));
diff --git a/sys/vm/vm_page.h b/sys/vm/vm_page.h
index a1a5d1d27baa..7846702aa8d1 100644
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@@ -325,7 +325,6 @@ extern struct mtx_padalign pa_lock[];
 #define	PG_FICTITIOUS	0x0004		/* physical page doesn't exist */
 #define	PG_ZERO		0x0008		/* page is zeroed */
 #define	PG_MARKER	0x0010		/* special queue marker page */
-#define	PG_SLAB		0x0020		/* object pointer is actually a slab */
 #define	PG_WINATCFLS	0x0040		/* flush dirty page on inactive q */
 #define	PG_NODUMP	0x0080		/* don't include this page in a dump */
 #define	PG_UNHOLDFREE	0x0100		/* delayed free of a held page */
diff --git a/sys/vm/vm_reserv.c b/sys/vm/vm_reserv.c
index c264a7644f7c..6ca5642807f6 100644
--- a/sys/vm/vm_reserv.c
+++ b/sys/vm/vm_reserv.c
@@ -502,8 +502,7 @@ vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred)
 	 * Look for an existing reservation.
 	 */
 	if (mpred != NULL) {
-		KASSERT(mpred->object == object ||
-		    (mpred->flags & PG_SLAB) != 0,
+		KASSERT(mpred->object == object,
 		    ("vm_reserv_alloc_page: object doesn't contain mpred"));
 		KASSERT(mpred->pindex < pindex,
 		    ("vm_reserv_alloc_page: mpred doesn't precede pindex"));