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System maps are prohibited from mapping vnode-backed objects. Take

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advantage of this restriction to avoid acquiring and releasing Giant when
wiring pages within a system map.

In collaboration with: tegge@
This commit is contained in:
Alan Cox 2004-09-11 18:49:59 +00:00
parent cf7b3b6562
commit 5e4bdb57cb
1 changed files with 8 additions and 8 deletions
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16
sys/vm/vm_fault.c
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@ -172,7 +172,7 @@ _unlock_things(struct faultstate *fs, int dealloc)
mtx_unlock(&Giant); mtx_unlock(&Giant);
fs->vp = NULL; fs->vp = NULL;
} }
if (dealloc) if (dealloc && !fs->map->system_map)
VM_UNLOCK_GIANT(); VM_UNLOCK_GIANT();
} }
@ -291,11 +291,14 @@ RetryFault:;
* *
* XXX vnode_pager_lock() can block without releasing the map lock. * XXX vnode_pager_lock() can block without releasing the map lock.
*/ */
mtx_lock(&Giant); if (!fs.map->system_map)
mtx_lock(&Giant);
VM_OBJECT_LOCK(fs.first_object); VM_OBJECT_LOCK(fs.first_object);
vm_object_reference_locked(fs.first_object); vm_object_reference_locked(fs.first_object);
fs.vp = vnode_pager_lock(fs.first_object); fs.vp = vnode_pager_lock(fs.first_object);
if (debug_mpsafevm) KASSERT(fs.vp == NULL || !fs.map->system_map,
("vm_fault: vnode-backed object mapped by system map"));
if (debug_mpsafevm && !fs.map->system_map)
mtx_unlock(&Giant); mtx_unlock(&Giant);
vm_object_pip_add(fs.first_object, 1); vm_object_pip_add(fs.first_object, 1);
@ -369,7 +372,8 @@ RetryFault:;
if (!vm_page_sleep_if_busy(fs.m, TRUE, "vmpfw")) if (!vm_page_sleep_if_busy(fs.m, TRUE, "vmpfw"))
vm_page_unlock_queues(); vm_page_unlock_queues();
atomic_add_int(&cnt.v_intrans, 1); atomic_add_int(&cnt.v_intrans, 1);
VM_UNLOCK_GIANT(); if (!fs.map->system_map)
VM_UNLOCK_GIANT();
vm_object_deallocate(fs.first_object); vm_object_deallocate(fs.first_object);
goto RetryFault; goto RetryFault;
} }
@ -1026,13 +1030,9 @@ vm_fault_wire(vm_map_t map, vm_offset_t start, vm_offset_t end,
* read-only sections. * read-only sections.
*/ */
for (va = start; va < end; va += PAGE_SIZE) { for (va = start; va < end; va += PAGE_SIZE) {
if (map->system_map)
mtx_lock(&Giant);
rv = vm_fault(map, va, rv = vm_fault(map, va,
user_wire ? VM_PROT_READ : VM_PROT_READ | VM_PROT_WRITE, user_wire ? VM_PROT_READ : VM_PROT_READ | VM_PROT_WRITE,
user_wire ? VM_FAULT_USER_WIRE : VM_FAULT_CHANGE_WIRING); user_wire ? VM_FAULT_USER_WIRE : VM_FAULT_CHANGE_WIRING);
if (map->system_map)
mtx_unlock(&Giant);
if (rv) { if (rv) {
if (va != start) if (va != start)
vm_fault_unwire(map, start, va, fictitious); vm_fault_unwire(map, start, va, fictitious);