Move pmap_collect() out of the machine-dependent code, rename it

to reflect its new location, and add page queue and flag locking.

Notes: (1) alpha, i386, and ia64 had identical implementations
of pmap_collect() in terms of machine-independent interfaces;
(2) sparc64 doesn't require it; (3) powerpc had it as a TODO.

2 files changed, 33 insertions, 2 deletions

diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
index 1511e4a..38bde18 100644
--- a/sys/vm/pmap.h
+++ b/sys/vm/pmap.h
@@ -89,13 +89,14 @@ typedef struct pmap_statistics *pmap_statistics_t;
 struct proc;
 struct thread;
 
+extern	int	 pmap_pagedaemon_waken;
+
 #ifdef __alpha__
 void		 pmap_page_is_free(vm_page_t m);
 #endif
 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);
-void		 pmap_collect(void);
 void		 pmap_copy(pmap_t, pmap_t, vm_offset_t, vm_size_t, vm_offset_t);
 void		 pmap_copy_page(vm_page_t, vm_page_t);
 void		 pmap_enter(pmap_t, vm_offset_t, vm_page_t, vm_prot_t,
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 00569a0..db27af9 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -109,6 +109,7 @@
 /* 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);
 static int vm_pageout_free_page_calc(vm_size_t count);
 struct proc *pageproc;
@@ -626,6 +627,35 @@ vm_pageout_page_free(vm_page_t m) {
 }
 
 /*
+ * 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
@@ -650,7 +680,7 @@ vm_pageout_scan(int pass)
 	/*
 	 * Do whatever cleanup that the pmap code can.
 	 */
-	pmap_collect();
+	vm_pageout_pmap_collect();
 	uma_reclaim();
 
 	addl_page_shortage_init = vm_pageout_deficit;