Author: alc Date: Wed Mar 15 17:43:45 2017 New Revision: 315318 URL: https://svnweb.freebsd.org/changeset/base/315318
Log: Relax the locking requirements for vm_object_page_noreuse(). While 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 Modified: head/sys/kern/vfs_default.c head/sys/vm/vm_object.c Modified: head/sys/kern/vfs_default.c ============================================================================== --- head/sys/kern/vfs_default.c Wed Mar 15 17:26:19 2017 (r315317) +++ head/sys/kern/vfs_default.c Wed Mar 15 17:43:45 2017 (r315318) @@ -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; Modified: head/sys/vm/vm_object.c ============================================================================== --- head/sys/vm/vm_object.c Wed Mar 15 17:26:19 2017 (r315317) +++ head/sys/vm/vm_object.c Wed Mar 15 17:43:45 2017 (r315318) @@ -1978,7 +1978,7 @@ vm_object_page_noreuse(vm_object_t objec 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) _______________________________________________ [email protected] mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "[email protected]"
