Reimplement the reclamation of PV entries. Specifically, perform

reclamation synchronously from get_pv_entry() instead of
asynchronously as part of the page daemon.  Additionally, limit the
reclamation to inactive pages unless allocation from the PV entry zone
or reclamation from the inactive queue fails.  Previously, reclamation
destroyed mappings to both inactive and active pages.  get_pv_entry()
still, however, wakes up the page daemon when reclamation occurs.  The
reason being that the page daemon may move some pages from the active
queue to the inactive queue, making some new pages available to future
reclamations.

Print the "reclaiming PV entries" message at most once per minute, but
don't stop printing it after the fifth time.  This way, we do not give
the impression that the problem has gone away.

Reviewed by: tegge

8 files changed, 190 insertions, 152 deletions

diff --git a/sys/alpha/alpha/pmap.c b/sys/alpha/alpha/pmap.c
index 39cd851..9ce77cd 100644
--- a/sys/alpha/alpha/pmap.c
+++ b/sys/alpha/alpha/pmap.c
@@ -317,11 +317,9 @@ static struct mtx allpmaps_lock;
  */
 static uma_zone_t pvzone;
 static int pv_entry_count = 0, pv_entry_max = 0, pv_entry_high_water = 0;
-int pmap_pagedaemon_waken;
 
 static PMAP_INLINE void	free_pv_entry(pv_entry_t pv);
-static pv_entry_t get_pv_entry(void);
-static pv_entry_t pv_entry_reclaim(pmap_t locked_pmap);
+static pv_entry_t get_pv_entry(pmap_t locked_pmap);
 static void	alpha_protection_init(void);
 static void	pmap_changebit(vm_page_t m, int bit, boolean_t setem);
 
@@ -1300,39 +1298,44 @@ free_pv_entry(pv_entry_t pv)
 /*
  * get a new pv_entry, allocating a block from the system
  * when needed.
- * the memory allocation is performed bypassing the malloc code
- * because of the possibility of allocations at interrupt time.
  */
 static pv_entry_t
-get_pv_entry(void)
-{
-	pv_entry_count++;
-	if ((pv_entry_count > pv_entry_high_water) &&
-		(pmap_pagedaemon_waken == 0)) {
-		pmap_pagedaemon_waken = 1;
-		wakeup (&vm_pages_needed);
-	}
-	return uma_zalloc(pvzone, M_NOWAIT);
-}
-
-/*
- * Reclaim a pv entry by removing a mapping to an inactive page.
- */
-static pv_entry_t
-pv_entry_reclaim(pmap_t locked_pmap)
+get_pv_entry(pmap_t locked_pmap)
 {
+	static const struct timeval printinterval = { 60, 0 };
+	static struct timeval lastprint;
+	struct vpgqueues *vpq;
 	pmap_t pmap;
 	pt_entry_t *pte, tpte;
-	pv_entry_t pv;
+	pv_entry_t allocated_pv, next_pv, pv;
 	vm_offset_t va;
 	vm_page_t m;
 
 	PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
-	TAILQ_FOREACH(m, &vm_page_queues[PQ_INACTIVE].pl, pageq) {
+	allocated_pv = uma_zalloc(pvzone, M_NOWAIT);
+	if (allocated_pv != NULL) {
+		pv_entry_count++;
+		if (pv_entry_count > pv_entry_high_water)
+			pagedaemon_wakeup();
+		else
+			return (allocated_pv);
+	}
+
+	/*
+	 * Reclaim pv entries: At first, destroy mappings to inactive
+	 * pages.  After that, if a pv entry is still needed, destroy
+	 * mappings to active pages.
+	 */
+	if (ratecheck(&lastprint, &printinterval))
+		printf("Approaching the limit on PV entries, "
+		    "increase the vm.pmap.shpgperproc tunable.\n");
+	vpq = &vm_page_queues[PQ_INACTIVE];
+retry:
+	TAILQ_FOREACH(m, &vpq->pl, pageq) {
 		if (m->hold_count || m->busy || (m->flags & PG_BUSY))
 			continue;
-		TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
+		TAILQ_FOREACH_SAFE(pv, &m->md.pv_list, pv_list, next_pv) {
 			va = pv->pv_va;
 			pmap = pv->pv_pmap;
 			if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap))
@@ -1342,7 +1345,7 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			tpte = *pte;
 			*pte = 0;
 			KASSERT((tpte & PG_W) == 0,
-			    ("pv_entry_reclaim: wired pte %#lx", tpte));
+			    ("get_pv_entry: wired pte %#lx", tpte));
 			if ((tpte & PG_FOR) == 0)
 				vm_page_flag_set(m, PG_REFERENCED);
 			if ((tpte & PG_FOW) == 0) {
@@ -1358,10 +1361,20 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			pmap_unuse_pt(pmap, va, pv->pv_ptem);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
-			return (pv);
+			if (allocated_pv == NULL)
+				allocated_pv = pv;
+			else
+				free_pv_entry(pv);
+		}
+	}
+	if (allocated_pv == NULL) {
+		if (vpq == &vm_page_queues[PQ_INACTIVE]) {
+			vpq = &vm_page_queues[PQ_ACTIVE];
+			goto retry;
 		}
+		panic("get_pv_entry: increase the vm.pmap.shpgperproc tunable");
 	}
-	panic("pv_entry_reclaim: increase vm.pmap.shpgperproc");
+	return (allocated_pv);
 }
 
 static int
@@ -1408,9 +1421,7 @@ pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t mpte, vm_page_t m)
 {
 	pv_entry_t pv;
 
-	pv = get_pv_entry();
-	if (pv == NULL)
-		pv = pv_entry_reclaim(pmap);
+	pv = get_pv_entry(pmap);
 	pv->pv_va = va;
 	pv->pv_pmap = pmap;
 	pv->pv_ptem = mpte;
diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
index d144849..6c7da48 100644
--- a/sys/amd64/amd64/pmap.c
+++ b/sys/amd64/amd64/pmap.c
@@ -185,7 +185,6 @@ static u_int64_t	DMPDPphys;	/* phys addr of direct mapped level 3 */
 static uma_zone_t pvzone;
 static struct vm_object pvzone_obj;
 static int pv_entry_count = 0, pv_entry_max = 0, pv_entry_high_water = 0;
-int pmap_pagedaemon_waken;
 
 /*
  * All those kernel PT submaps that BSD is so fond of
@@ -200,8 +199,7 @@ struct msgbuf *msgbufp = 0;
 static caddr_t crashdumpmap;
 
 static PMAP_INLINE void	free_pv_entry(pv_entry_t pv);
-static pv_entry_t get_pv_entry(void);
-static pv_entry_t pv_entry_reclaim(pmap_t locked_pmap);
+static pv_entry_t get_pv_entry(pmap_t locked_pmap);
 static void	pmap_clear_ptes(vm_page_t m, long bit);
 
 static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq,
@@ -1428,40 +1426,45 @@ free_pv_entry(pv_entry_t pv)
 /*
  * get a new pv_entry, allocating a block from the system
  * when needed.
- * the memory allocation is performed bypassing the malloc code
- * because of the possibility of allocations at interrupt time.
  */
 static pv_entry_t
-get_pv_entry(void)
-{
-	pv_entry_count++;
-	if ((pv_entry_count > pv_entry_high_water) &&
-		(pmap_pagedaemon_waken == 0)) {
-		pmap_pagedaemon_waken = 1;
-		wakeup (&vm_pages_needed);
-	}
-	return uma_zalloc(pvzone, M_NOWAIT);
-}
-
-/*
- * Reclaim a pv entry by removing a mapping to an inactive page.
- */
-static pv_entry_t
-pv_entry_reclaim(pmap_t locked_pmap)
+get_pv_entry(pmap_t locked_pmap)
 {
+	static const struct timeval printinterval = { 60, 0 };
+	static struct timeval lastprint;
+	struct vpgqueues *vpq;
 	pd_entry_t ptepde;
 	pmap_t pmap;
 	pt_entry_t *pte, tpte;
-	pv_entry_t pv;
+	pv_entry_t allocated_pv, next_pv, pv;
 	vm_offset_t va;
 	vm_page_t m;
 
 	PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
-	TAILQ_FOREACH(m, &vm_page_queues[PQ_INACTIVE].pl, pageq) {
+	allocated_pv = uma_zalloc(pvzone, M_NOWAIT);
+	if (allocated_pv != NULL) {
+		pv_entry_count++;
+		if (pv_entry_count > pv_entry_high_water)
+			pagedaemon_wakeup();
+		else
+			return (allocated_pv);
+	}
+
+	/*
+	 * Reclaim pv entries: At first, destroy mappings to inactive
+	 * pages.  After that, if a pv entry is still needed, destroy
+	 * mappings to active pages.
+	 */
+	if (ratecheck(&lastprint, &printinterval))
+		printf("Approaching the limit on PV entries, "
+		    "increase the vm.pmap.shpgperproc tunable.\n");
+	vpq = &vm_page_queues[PQ_INACTIVE];
+retry:
+	TAILQ_FOREACH(m, &vpq->pl, pageq) {
 		if (m->hold_count || m->busy || (m->flags & PG_BUSY))
 			continue;
-		TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
+		TAILQ_FOREACH_SAFE(pv, &m->md.pv_list, pv_list, next_pv) {
 			va = pv->pv_va;
 			pmap = pv->pv_pmap;
 			if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap))
@@ -1470,12 +1473,12 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			pte = pmap_pte_pde(pmap, va, &ptepde);
 			tpte = pte_load_clear(pte);
 			KASSERT((tpte & PG_W) == 0,
-			    ("pv_entry_reclaim: wired pte %#lx", tpte));
+			    ("get_pv_entry: wired pte %#lx", tpte));
 			if (tpte & PG_A)
 				vm_page_flag_set(m, PG_REFERENCED);
 			if (tpte & PG_M) {
 				KASSERT((tpte & PG_RW),
-	("pv_entry_reclaim: modified page not writable: va: %#lx, pte: %#lx",
+	("get_pv_entry: modified page not writable: va: %#lx, pte: %#lx",
 				    va, tpte));
 				if (pmap_track_modified(va))
 					vm_page_dirty(m);
@@ -1489,10 +1492,20 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			pmap_unuse_pt(pmap, va, ptepde);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
-			return (pv);
+			if (allocated_pv == NULL)
+				allocated_pv = pv;
+			else
+				free_pv_entry(pv);
 		}
 	}
-	panic("pv_entry_reclaim: increase vm.pmap.shpgperproc");
+	if (allocated_pv == NULL) {
+		if (vpq == &vm_page_queues[PQ_INACTIVE]) {
+			vpq = &vm_page_queues[PQ_ACTIVE];
+			goto retry;
+		}
+		panic("get_pv_entry: increase the vm.pmap.shpgperproc tunable");
+	}
+	return (allocated_pv);
 }
 
 static void
@@ -1531,11 +1544,7 @@ pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
 {
 	pv_entry_t pv;
 
-	pv = get_pv_entry();
-	if (pv == NULL) {
-		pv_entry_count--;
-		pv = pv_entry_reclaim(pmap);
-	}
+	pv = get_pv_entry(pmap);
 	pv->pv_va = va;
 	pv->pv_pmap = pmap;
 
diff --git a/sys/i386/i386/pmap.c b/sys/i386/i386/pmap.c
index d6f6541..36aac8d 100644
--- a/sys/i386/i386/pmap.c
+++ b/sys/i386/i386/pmap.c
@@ -208,7 +208,6 @@ static uma_zone_t pdptzone;
 static uma_zone_t pvzone;
 static struct vm_object pvzone_obj;
 static int pv_entry_count = 0, pv_entry_max = 0, pv_entry_high_water = 0;
-int pmap_pagedaemon_waken;
 
 /*
  * All those kernel PT submaps that BSD is so fond of
@@ -255,8 +254,7 @@ SYSCTL_INT(_debug, OID_AUTO, PMAP1unchanged, CTLFLAG_RD,
 static struct mtx PMAP2mutex;
 
 static PMAP_INLINE void	free_pv_entry(pv_entry_t pv);
-static pv_entry_t get_pv_entry(void);
-static pv_entry_t pv_entry_reclaim(pmap_t locked_pmap);
+static pv_entry_t get_pv_entry(pmap_t locked_pmap);
 static void	pmap_clear_ptes(vm_page_t m, int bit);
 
 static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t sva);
@@ -1442,40 +1440,45 @@ free_pv_entry(pv_entry_t pv)
 /*
  * get a new pv_entry, allocating a block from the system
  * when needed.
- * the memory allocation is performed bypassing the malloc code
- * because of the possibility of allocations at interrupt time.
  */
 static pv_entry_t
-get_pv_entry(void)
-{
-	pv_entry_count++;
-	if ((pv_entry_count > pv_entry_high_water) &&
-		(pmap_pagedaemon_waken == 0)) {
-		pmap_pagedaemon_waken = 1;
-		wakeup (&vm_pages_needed);
-	}
-	return uma_zalloc(pvzone, M_NOWAIT);
-}
-
-/*
- * Reclaim a pv entry by removing a mapping to an inactive page.
- */
-static pv_entry_t
-pv_entry_reclaim(pmap_t locked_pmap)
+get_pv_entry(pmap_t locked_pmap)
 {
+	static const struct timeval printinterval = { 60, 0 };
+	static struct timeval lastprint;
+	struct vpgqueues *vpq;
 	pmap_t pmap;
 	pt_entry_t *pte, tpte;
-	pv_entry_t pv;
+	pv_entry_t allocated_pv, next_pv, pv;
 	vm_offset_t va;
 	vm_page_t m;
 
 	PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+	allocated_pv = uma_zalloc(pvzone, M_NOWAIT);
+	if (allocated_pv != NULL) {
+		pv_entry_count++;
+		if (pv_entry_count > pv_entry_high_water)
+			pagedaemon_wakeup();
+		else
+			return (allocated_pv);
+	}
+
+	/*
+	 * Reclaim pv entries: At first, destroy mappings to inactive
+	 * pages.  After that, if a pv entry is still needed, destroy
+	 * mappings to active pages.
+	 */
+	if (ratecheck(&lastprint, &printinterval))
+		printf("Approaching the limit on PV entries, "
+		    "increase the vm.pmap.shpgperproc tunable.\n");
+	vpq = &vm_page_queues[PQ_INACTIVE];
+retry:
 	sched_pin();
-	TAILQ_FOREACH(m, &vm_page_queues[PQ_INACTIVE].pl, pageq) {
+	TAILQ_FOREACH(m, &vpq->pl, pageq) {
 		if (m->hold_count || m->busy || (m->flags & PG_BUSY))
 			continue;
-		TAILQ_FOREACH(pv, &m->md.pv_list, pv_list) {
+		TAILQ_FOREACH_SAFE(pv, &m->md.pv_list, pv_list, next_pv) {
 			va = pv->pv_va;
 			pmap = pv->pv_pmap;
 			if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap))
@@ -1484,13 +1487,12 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			pte = pmap_pte_quick(pmap, va);
 			tpte = pte_load_clear(pte);
 			KASSERT((tpte & PG_W) == 0,
-			    ("pv_entry_reclaim: wired pte %#jx",
-			    (uintmax_t)tpte));
+			    ("get_pv_entry: wired pte %#jx", (uintmax_t)tpte));
 			if (tpte & PG_A)
 				vm_page_flag_set(m, PG_REFERENCED);
 			if (tpte & PG_M) {
 				KASSERT((tpte & PG_RW),
-	("pv_entry_reclaim: modified page not writable: va: %#x, pte: %#jx",
+	("get_pv_entry: modified page not writable: va: %#x, pte: %#jx",
 				    va, (uintmax_t)tpte));
 				if (pmap_track_modified(va))
 					vm_page_dirty(m);
@@ -1504,12 +1506,21 @@ pv_entry_reclaim(pmap_t locked_pmap)
 			pmap_unuse_pt(pmap, va);
 			if (pmap != locked_pmap)
 				PMAP_UNLOCK(pmap);
-			sched_unpin();
-			return (pv);
+			if (allocated_pv == NULL)
+				allocated_pv = pv;
+			else
+				free_pv_entry(pv);
 		}
 	}
 	sched_unpin();
-	panic("pv_entry_reclaim: increase vm.pmap.shpgperproc");
+	if (allocated_pv == NULL) {
+		if (vpq == &vm_page_queues[PQ_INACTIVE]) {
+			vpq = &vm_page_queues[PQ_ACTIVE];
+			goto retry;
+		}
+		panic("get_pv_entry: increase the vm.pmap.shpgperproc tunable");
+	}
+	return (allocated_pv);
 }
 
 static void
@@ -1548,11 +1559,7 @@ pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
 {
 	pv_entry_t pv;
 
-	pv = get_pv_entry();
-	if (pv == NULL) {
-		pv_entry_count--;
-		pv = pv_entry_reclaim(pmap);
-	}
+	pv = get_pv_entry(pmap);
 	pv->pv_va = va;
 	pv->pv_pmap = pmap;
 
diff --git a/sys/ia64/ia64/pmap.c b/sys/ia64/ia64/pmap.c
index a21cead..0c900b8 100644
--- a/sys/ia64/ia64/pmap.c
+++ b/sys/ia64/ia64/pmap.c
@@ -198,7 +198,6 @@ struct mtx pmap_ridmutex;
  */
 static uma_zone_t pvzone;
 static int pv_entry_count = 0, pv_entry_max = 0, pv_entry_high_water = 0;
-int pmap_pagedaemon_waken;
 
 /*
  * Data for allocating PTEs for user processes.
@@ -232,11 +231,15 @@ static int pmap_vhpt_population(SYSCTL_HANDLER_ARGS);
 SYSCTL_PROC(_machdep_vhpt, OID_AUTO, population, CTLTYPE_INT | CTLFLAG_RD,
     NULL, 0, pmap_vhpt_population, "I", "");
 
+static struct ia64_lpte *pmap_find_vhpt(vm_offset_t va);
+
 static PMAP_INLINE void	free_pv_entry(pv_entry_t pv);
-static pv_entry_t get_pv_entry(void);
+static pv_entry_t get_pv_entry(pmap_t locked_pmap);
 
 static pmap_t	pmap_install(pmap_t);
 static void	pmap_invalidate_all(pmap_t pmap);
+static int	pmap_remove_pte(pmap_t pmap, struct ia64_lpte *pte,
+		    vm_offset_t va, pv_entry_t pv, int freepte);
 
 vm_offset_t
 pmap_steal_memory(vm_size_t size)
@@ -807,19 +810,69 @@ free_pv_entry(pv_entry_t pv)
 /*
  * get a new pv_entry, allocating a block from the system
  * when needed.
- * the memory allocation is performed bypassing the malloc code
- * because of the possibility of allocations at interrupt time.
  */
 static pv_entry_t
-get_pv_entry(void)
+get_pv_entry(pmap_t locked_pmap)
 {
-	pv_entry_count++;
-	if ((pv_entry_count > pv_entry_high_water) &&
-		(pmap_pagedaemon_waken == 0)) {
-		pmap_pagedaemon_waken = 1;
-		wakeup (&vm_pages_needed);
+	static const struct timeval printinterval = { 60, 0 };
+	static struct timeval lastprint;
+	struct vpgqueues *vpq;
+	struct ia64_lpte *pte;
+	pmap_t oldpmap, pmap;
+	pv_entry_t allocated_pv, next_pv, pv;
+	vm_offset_t va;
+	vm_page_t m;
+
+	PMAP_LOCK_ASSERT(locked_pmap, MA_OWNED);
+	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+	allocated_pv = uma_zalloc(pvzone, M_NOWAIT);
+	if (allocated_pv != NULL) {
+		pv_entry_count++;
+		if (pv_entry_count > pv_entry_high_water)
+			pagedaemon_wakeup();
+		else
+			return (allocated_pv);
+	}
+
+	/*
+	 * Reclaim pv entries: At first, destroy mappings to inactive
+	 * pages.  After that, if a pv entry is still needed, destroy
+	 * mappings to active pages.
+	 */
+	if (ratecheck(&lastprint, &printinterval))
+		printf("Approaching the limit on PV entries, "
+		    "increase the vm.pmap.shpgperproc tunable.\n");
+	vpq = &vm_page_queues[PQ_INACTIVE];
+retry:
+	TAILQ_FOREACH(m, &vpq->pl, pageq) {
+		if (m->hold_count || m->busy || (m->flags & PG_BUSY))
+			continue;
+		TAILQ_FOREACH_SAFE(pv, &m->md.pv_list, pv_list, next_pv) {
+			va = pv->pv_va;
+			pmap = pv->pv_pmap;
+			if (pmap != locked_pmap && !PMAP_TRYLOCK(pmap))
+				continue;
+			oldpmap = pmap_install(pmap);
+			pte = pmap_find_vhpt(va);
+			KASSERT(pte != NULL, ("pte"));
+			pmap_remove_pte(pmap, pte, va, pv, 1);
+			pmap_install(oldpmap);
+			if (pmap != locked_pmap)
+				PMAP_UNLOCK(pmap);
+			if (allocated_pv == NULL)
+				allocated_pv = pv;
+			else
+				free_pv_entry(pv);
+		}
+	}
+	if (allocated_pv == NULL) {
+		if (vpq == &vm_page_queues[PQ_INACTIVE]) {
+			vpq = &vm_page_queues[PQ_ACTIVE];
+			goto retry;
+		}
+		panic("get_pv_entry: increase the vm.pmap.shpgperproc tunable");
 	}
-	return uma_zalloc(pvzone, M_NOWAIT);
+	return (allocated_pv);
 }
 
 /*
@@ -959,9 +1012,7 @@ pmap_insert_entry(pmap_t pmap, vm_offset_t va, vm_page_t m)
 {
 	pv_entry_t pv;
 
-	pv = get_pv_entry();
-	if (pv == NULL)
-		panic("no pv entries: increase vm.pmap.shpgperproc");
+	pv = get_pv_entry(pmap);
 	pv->pv_pmap = pmap;
 	pv->pv_va = va;
 
diff --git a/sys/powerpc/powerpc/pmap.c b/sys/powerpc/powerpc/pmap.c
index 45319f0..91b645a 100644
--- a/sys/powerpc/powerpc/pmap.c
+++ b/sys/powerpc/powerpc/pmap.c
@@ -197,8 +197,6 @@ int	pmap_bootstrapped = 0;
 struct		msgbuf *msgbufp;
 vm_offset_t	msgbuf_phys;
 
-int pmap_pagedaemon_waken;
-
 /*
  * Map of physical memory regions.
  */
diff --git a/sys/sparc64/sparc64/pmap.c b/sys/sparc64/sparc64/pmap.c
index 9e4ff8b..e521022 100644
--- a/sys/sparc64/sparc64/pmap.c
+++ b/sys/sparc64/sparc64/pmap.c
@@ -114,8 +114,6 @@
 struct msgbuf *msgbufp;
 vm_paddr_t msgbuf_phys;
 
-int pmap_pagedaemon_waken;
-
 /*
  * Map of physical memory reagions.
  */
diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
index d5b64c3..2379171 100644
--- a/sys/vm/pmap.h
+++ b/sys/vm/pmap.h
@@ -90,8 +90,6 @@ struct thread;
  */
 extern vm_offset_t kernel_vm_end;
 
-extern	int	 pmap_pagedaemon_waken;
-
 void		 pmap_change_wiring(pmap_t, vm_offset_t, boolean_t);
 void		 pmap_clear_modify(vm_page_t m);
 void		 pmap_clear_reference(vm_page_t m);
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 6860dd6..0a56ca1 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -113,7 +113,6 @@ __FBSDID("$FreeBSD$");
 /* the kernel process "vm_pageout"*/
 static void vm_pageout(void);
 static int vm_pageout_clean(vm_page_t);
-static void vm_pageout_pmap_collect(void);
 static void vm_pageout_scan(int pass);
 
 struct proc *pageproc;
@@ -667,35 +666,6 @@ vm_pageout_map_deactivate_pages(map, desired)
 #endif		/* !defined(NO_SWAPPING) */
 
 /*
- * This routine is very drastic, but can save the system
- * in a pinch.
- */
-static void
-vm_pageout_pmap_collect(void)
-{
-	int i;
-	vm_page_t m;
-	static int warningdone;
-
-	if (pmap_pagedaemon_waken == 0)
-		return;
-	if (warningdone < 5) {
-		printf("collecting pv entries -- suggest increasing PMAP_SHPGPERPROC\n");
-		warningdone++;
-	}
-	vm_page_lock_queues();
-	for (i = 0; i < vm_page_array_size; i++) {
-		m = &vm_page_array[i];
-		if (m->wire_count || m->hold_count || m->busy ||
-		    (m->flags & (PG_BUSY | PG_UNMANAGED)))
-			continue;
-		pmap_remove_all(m);
-	}
-	vm_page_unlock_queues();
-	pmap_pagedaemon_waken = 0;
-}
-	
-/*
  *	vm_pageout_scan does the dirty work for the pageout daemon.
  */
 static void
@@ -723,10 +693,6 @@ vm_pageout_scan(int pass)
 	 * We do this explicitly after the caches have been drained above.
 	 */
 	uma_reclaim();
-	/*
-	 * Do whatever cleanup that the pmap code can.
-	 */
-	vm_pageout_pmap_collect();
 
 	addl_page_shortage_init = atomic_readandclear_int(&vm_pageout_deficit);