From a71ff79234d3c3aeed5f10bdf3963df1d991ea85 Mon Sep 17 00:00:00 2001
From: alc <alc@FreeBSD.org>
Date: Fri, 24 Oct 2003 06:43:04 +0000
Subject: [PATCH]  - Push down Giant from vm_pageout() to vm_pageout_scan(),
 freeing    vm_pageout_page_stats() from Giant.  - Modify vm_pager_put_pages()
 and vm_pager_page_unswapped() to expect the    vm object to be locked on
 entry.  (All of the pager routines now expect    this.)

---
 sys/vm/swap_pager.c  |  7 ++++---
 sys/vm/vm_pageout.c  | 11 ++++-------
 sys/vm/vm_pager.h    |  6 ++++--
 sys/vm/vnode_pager.c |  2 ++
 4 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 4013dfdd942b..9beff9255ccf 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -1187,6 +1187,7 @@ swap_pager_putpages(vm_object_t object, vm_page_t *m, int count,
 		    m[0]->object
 		);
 	}
+	VM_OBJECT_UNLOCK(object);
 	/*
 	 * Step 1
 	 *
@@ -1368,6 +1369,7 @@ swap_pager_putpages(vm_object_t object, vm_page_t *m, int count,
 		swp_pager_async_iodone(bp);
 		splx(s);
 	}
+	VM_OBJECT_LOCK(object);
 }
 
 /*
@@ -1652,13 +1654,13 @@ swp_pager_force_pagein(struct swblock *swap, int idx)
 	m = vm_page_grab(object, pindex + idx, VM_ALLOC_NORMAL|VM_ALLOC_RETRY);
 	if (m->valid == VM_PAGE_BITS_ALL) {
 		vm_object_pip_subtract(object, 1);
-		VM_OBJECT_UNLOCK(object);
 		vm_page_lock_queues();
 		vm_page_activate(m);
 		vm_page_dirty(m);
 		vm_page_wakeup(m);
 		vm_page_unlock_queues();
 		vm_pager_page_unswapped(m);
+		VM_OBJECT_UNLOCK(object);
 		return;
 	}
 
@@ -1666,14 +1668,13 @@ swp_pager_force_pagein(struct swblock *swap, int idx)
 	    VM_PAGER_OK)
 		panic("swap_pager_force_pagein: read from swap failed");/*XXX*/
 	vm_object_pip_subtract(object, 1);
-	VM_OBJECT_UNLOCK(object);
-
 	vm_page_lock_queues();
 	vm_page_dirty(m);
 	vm_page_dontneed(m);
 	vm_page_wakeup(m);
 	vm_page_unlock_queues();
 	vm_pager_page_unswapped(m);
+	VM_OBJECT_UNLOCK(object);
 }
 
 
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c
index 53e60139d094..471f9b39349b 100644
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@@ -362,12 +362,13 @@ vm_pageout_clean(m)
 int
 vm_pageout_flush(vm_page_t *mc, int count, int flags)
 {
-	vm_object_t object;
+	vm_object_t object = mc[0]->object;
 	int pageout_status[count];
 	int numpagedout = 0;
 	int i;
 
 	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	/*
 	 * Initiate I/O.  Bump the vm_page_t->busy counter and
 	 * mark the pages read-only.
@@ -385,16 +386,13 @@ vm_pageout_flush(vm_page_t *mc, int count, int flags)
 		vm_page_io_start(mc[i]);
 		pmap_page_protect(mc[i], VM_PROT_READ);
 	}
-	object = mc[0]->object;
 	vm_page_unlock_queues();
 	vm_object_pip_add(object, count);
-	VM_OBJECT_UNLOCK(object);
 
 	vm_pager_put_pages(object, mc, count,
 	    (flags | ((object == kernel_object) ? VM_PAGER_PUT_SYNC : 0)),
 	    pageout_status);
 
-	VM_OBJECT_LOCK(object);
 	vm_page_lock_queues();
 	for (i = 0; i < count; i++) {
 		vm_page_t mt = mc[i];
@@ -669,7 +667,7 @@ vm_pageout_scan(int pass)
 	int s;
 	struct thread *td;
 
-	GIANT_REQUIRED;
+	mtx_lock(&Giant);
 	/*
 	 * Decrease registered cache sizes.
 	 */
@@ -1224,6 +1222,7 @@ vm_pageout_scan(int pass)
 			wakeup(&cnt.v_free_count);
 		}
 	}
+	mtx_unlock(&Giant);
 }
 
 /*
@@ -1324,8 +1323,6 @@ vm_pageout()
 {
 	int error, pass, s;
 
-	mtx_lock(&Giant);
-
 	/*
 	 * Initialize some paging parameters.
 	 */
diff --git a/sys/vm/vm_pager.h b/sys/vm/vm_pager.h
index 390a769a63a7..d4f43e3289be 100644
--- a/sys/vm/vm_pager.h
+++ b/sys/vm/vm_pager.h
@@ -141,7 +141,8 @@ vm_pager_put_pages(
 	int flags,
 	int *rtvals
 ) {
-	GIANT_REQUIRED;
+
+	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 	(*pagertab[object->type]->pgo_putpages)
 	    (object, m, count, flags, rtvals);
 }
@@ -186,7 +187,8 @@ vm_pager_has_page(
 static __inline void
 vm_pager_page_unswapped(vm_page_t m)
 {
-	GIANT_REQUIRED;
+
+	VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
 	if (pagertab[m->object->type]->pgo_pageunswapped)
 		(*pagertab[m->object->type]->pgo_pageunswapped)(m);
 }
diff --git a/sys/vm/vnode_pager.c b/sys/vm/vnode_pager.c
index 16602d7b502e..08daacad821c 100644
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
@@ -953,6 +953,7 @@ vnode_pager_putpages(object, m, count, sync, rtvals)
 	 * Call device-specific putpages function
 	 */
 	vp = object->handle;
+	VM_OBJECT_UNLOCK(object);
 	if (vp->v_type != VREG)
 		mp = NULL;
 	(void)vn_start_write(vp, &mp, V_WAIT);
@@ -960,6 +961,7 @@ vnode_pager_putpages(object, m, count, sync, rtvals)
 	KASSERT(rtval != EOPNOTSUPP, 
 	    ("vnode_pager: stale FS putpages\n"));
 	vn_finished_write(mp);
+	VM_OBJECT_LOCK(object);
 }