With Alfred's permission, remove vm_mtx in favor of a fine-grained approach

(this commit is just the first stage).  Also add various GIANT_ macros to
formalize the removal of Giant, making it easy to test in a more piecemeal
fashion. These macros will allow us to test fine-grained locks to a degree
before removing Giant, and also after, and to remove Giant in a piecemeal
fashion via sysctl's on those subsystems which the authors believe can
operate without Giant.

1 files changed, 12 insertions, 58 deletions

diff --git a/sys/vm/vm_kern.c b/sys/vm/vm_kern.c
index 38f969e..96199cd 100644
--- a/sys/vm/vm_kern.c
+++ b/sys/vm/vm_kern.c
@@ -104,17 +104,13 @@ kmem_alloc_pageable(map, size)
 {
 	vm_offset_t addr;
 	int result;
-	int hadvmlock;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
+	GIANT_REQUIRED;
+
 	size = round_page(size);
 	addr = vm_map_min(map);
 	result = vm_map_find(map, NULL, (vm_offset_t) 0,
 	    &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, 0);
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	if (result != KERN_SUCCESS) {
 		return (0);
 	}
@@ -135,17 +131,12 @@ kmem_alloc_nofault(map, size)
 	vm_offset_t addr;
 	int result;
 
-	int hadvmlock;
+	GIANT_REQUIRED;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
 	size = round_page(size);
 	addr = vm_map_min(map);
 	result = vm_map_find(map, NULL, (vm_offset_t) 0,
 	    &addr, size, TRUE, VM_PROT_ALL, VM_PROT_ALL, MAP_NOFAULT);
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	if (result != KERN_SUCCESS) {
 		return (0);
 	}
@@ -164,11 +155,9 @@ kmem_alloc(map, size)
 	vm_offset_t addr;
 	vm_offset_t offset;
 	vm_offset_t i;
-	int hadvmlock;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
+	GIANT_REQUIRED;
+
 	size = round_page(size);
 
 	/*
@@ -184,8 +173,6 @@ kmem_alloc(map, size)
 	vm_map_lock(map);
 	if (vm_map_findspace(map, vm_map_min(map), size, &addr)) {
 		vm_map_unlock(map);
-		if (!hadvmlock)
-			mtx_unlock(&vm_mtx);
 		return (0);
 	}
 	offset = addr - VM_MIN_KERNEL_ADDRESS;
@@ -230,8 +217,6 @@ kmem_alloc(map, size)
 
 	(void) vm_map_pageable(map, (vm_offset_t) addr, addr + size, FALSE);
 
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	return (addr);
 }
 
@@ -250,16 +235,9 @@ kmem_free(map, addr, size)
 	vm_offset_t addr;
 	vm_size_t size;
 {
-	int hadvmlock;
-
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
+	GIANT_REQUIRED;
 
 	(void) vm_map_remove(map, trunc_page(addr), round_page(addr + size));
-
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 }
 
 /*
@@ -282,11 +260,8 @@ kmem_suballoc(parent, min, max, size)
 {
 	int ret;
 	vm_map_t result;
-	int hadvmlock;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
+	GIANT_REQUIRED;
 
 	size = round_page(size);
 
@@ -304,8 +279,6 @@ kmem_suballoc(parent, min, max, size)
 		panic("kmem_suballoc: cannot create submap");
 	if (vm_map_submap(parent, *min, *max, result) != KERN_SUCCESS)
 		panic("kmem_suballoc: unable to change range to submap");
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	return (result);
 }
 
@@ -343,12 +316,9 @@ kmem_malloc(map, size, flags)
 	vm_map_entry_t entry;
 	vm_offset_t addr;
 	vm_page_t m;
-	int hadvmlock;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
-		
+	GIANT_REQUIRED;
+
 	size = round_page(size);
 	addr = vm_map_min(map);
 
@@ -444,13 +414,9 @@ retry:
 	}
 	vm_map_unlock(map);
 
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	return (addr);
 
 bad:	
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	return (0);
 }
 
@@ -469,11 +435,8 @@ kmem_alloc_wait(map, size)
 	vm_size_t size;
 {
 	vm_offset_t addr;
-	int hadvmlock;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
+	GIANT_REQUIRED;
 
 	size = round_page(size);
 
@@ -488,17 +451,13 @@ kmem_alloc_wait(map, size)
 		/* no space now; see if we can ever get space */
 		if (vm_map_max(map) - vm_map_min(map) < size) {
 			vm_map_unlock(map);
-			if (!hadvmlock)
-				mtx_unlock(&vm_mtx);
 			return (0);
 		}
 		vm_map_unlock(map);
-		msleep(map, &vm_mtx, PVM, "kmaw", 0);
+		tsleep(map, PVM, "kmaw", 0);
 	}
 	vm_map_insert(map, NULL, (vm_offset_t) 0, addr, addr + size, VM_PROT_ALL, VM_PROT_ALL, 0);
 	vm_map_unlock(map);
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 	return (addr);
 }
 
@@ -514,17 +473,12 @@ kmem_free_wakeup(map, addr, size)
 	vm_offset_t addr;
 	vm_size_t size;
 {
-	int hadvmlock;
+	GIANT_REQUIRED;
 
-	hadvmlock = mtx_owned(&vm_mtx);
-	if (!hadvmlock)
-		mtx_lock(&vm_mtx);
 	vm_map_lock(map);
 	(void) vm_map_delete(map, trunc_page(addr), round_page(addr + size));
 	wakeup(map);
 	vm_map_unlock(map);
-	if (!hadvmlock)
-		mtx_unlock(&vm_mtx);
 }
 
 /*