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Code Issues Releases Activity

Relax the locking requirements for vm_object_page_noreuse(). While

Browse Source 
reviewing all uses of OFF_TO_IDX(), I observed that
vm_object_page_noreuse() is requiring an exclusive lock on the object
when, in fact, a shared lock suffices.

Reviewed by:	kib, markj
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D10011
This commit is contained in:
Alan Cox 2017-03-15 17:43:45 +00:00
parent 538ab9e64e
commit 52d1addaa1
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=315318
2 changed files with 3 additions and 3 deletions
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4
sys/kern/vfs_default.c
View File

@ -1100,10 +1100,10 @@ vop_stdadvise(struct vop_advise_args *ap)
if (vp->v_object != NULL) {
start = trunc_page(ap->a_start);
end = round_page(ap->a_end);
VM_OBJECT_WLOCK(vp->v_object);
VM_OBJECT_RLOCK(vp->v_object);
vm_object_page_noreuse(vp->v_object, OFF_TO_IDX(start),
OFF_TO_IDX(end));
VM_OBJECT_WUNLOCK(vp->v_object);
VM_OBJECT_RUNLOCK(vp->v_object);
}
bo = &vp->v_bufobj;

2
sys/vm/vm_object.c
View File

@ -1978,7 +1978,7 @@ vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end)
struct mtx *mtx, *new_mtx;
vm_page_t p, next;
VM_OBJECT_ASSERT_WLOCKED(object);
VM_OBJECT_ASSERT_LOCKED(object);
KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0,
("vm_object_page_noreuse: illegal object %p", object));
if (object->resident_page_count == 0)