svn commit: r250790 - user/attilio/vmobj-readlock/sys/vm
Attilio Rao
attilio at FreeBSD.org
Sat May 18 22:42:06 UTC 2013
Author: attilio
Date: Sat May 18 22:42:05 2013
New Revision: 250790
URL: http://svnweb.freebsd.org/changeset/base/250790
Log:
Convert vm_map_pmap_enter() to work with read lock for most of the
cases.
Sponsored by: EMC / Isilon storage division
Modified:
user/attilio/vmobj-readlock/sys/vm/vm_map.c
user/attilio/vmobj-readlock/sys/vm/vm_object.h
Modified: user/attilio/vmobj-readlock/sys/vm/vm_map.c
==============================================================================
--- user/attilio/vmobj-readlock/sys/vm/vm_map.c Sat May 18 22:16:42 2013 (r250789)
+++ user/attilio/vmobj-readlock/sys/vm/vm_map.c Sat May 18 22:42:05 2013 (r250790)
@@ -1806,18 +1806,27 @@ vm_map_pmap_enter(vm_map_t map, vm_offse
if ((prot & (VM_PROT_READ | VM_PROT_EXECUTE)) == 0 || object == NULL)
return;
- VM_OBJECT_WLOCK(object);
+ VM_OBJECT_RLOCK(object);
if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
- pmap_object_init_pt(map->pmap, addr, object, pindex, size);
- goto unlock_return;
+ VM_OBJECT_RUNLOCK(object);
+ VM_OBJECT_WLOCK(object);
+ if (object->type == OBJT_DEVICE || object->type == OBJT_SG) {
+ pmap_object_init_pt(map->pmap, addr, object, pindex,
+ size);
+ VM_OBJECT_WUNLOCK(object);
+ return;
+ }
+ VM_OBJECT_LOCK_DOWNGRADE(object);
}
psize = atop(size);
if (psize > MAX_INIT_PT && (flags & MAP_PREFAULT_PARTIAL) != 0)
psize = MAX_INIT_PT;
if (psize + pindex > object->size) {
- if (object->size < pindex)
- goto unlock_return;
+ if (object->size < pindex) {
+ VM_OBJECT_RUNLOCK(object);
+ return;
+ }
psize = object->size - pindex;
}
@@ -1856,8 +1865,7 @@ vm_map_pmap_enter(vm_map_t map, vm_offse
if (p_start != NULL)
pmap_enter_object(map->pmap, start, addr + ptoa(psize),
p_start, prot);
-unlock_return:
- VM_OBJECT_WUNLOCK(object);
+ VM_OBJECT_RUNLOCK(object);
}
/*
Modified: user/attilio/vmobj-readlock/sys/vm/vm_object.h
==============================================================================
--- user/attilio/vmobj-readlock/sys/vm/vm_object.h Sat May 18 22:16:42 2013 (r250789)
+++ user/attilio/vmobj-readlock/sys/vm/vm_object.h Sat May 18 22:42:05 2013 (r250790)
@@ -223,6 +223,8 @@ extern struct vm_object kmem_object_stor
rw_assert(&(object)->lock, RA_RLOCKED)
#define VM_OBJECT_ASSERT_WLOCKED(object) \
rw_assert(&(object)->lock, RA_WLOCKED)
+#define VM_OBJECT_LOCK_DOWNGRADE(object) \
+ rw_downgrade(&(object)->lock)
#define VM_OBJECT_RLOCK(object) \
rw_rlock(&(object)->lock)
#define VM_OBJECT_RUNLOCK(object) \
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