Date: Wed, 15 Mar 2017 13:06:26 -0500 From: Alan Cox <alc@rice.edu> To: Benjamin Kaduk <bjkfbsd@gmail.com>, Alan Cox <alc@freebsd.org> Cc: "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "svn-src-head@freebsd.org" <svn-src-head@freebsd.org> Subject: Re: svn commit: r315318 - in head/sys: kern vm Message-ID: <4fd159d0-6509-98a9-7af0-6efada1def26@rice.edu> In-Reply-To: <CAJ5_RoCZKumshQ_17g5qqH2Q2A5s=NzMmThxOurJkGhU=mogyA@mail.gmail.com> References: <201703151743.v2FHhjLn066656@repo.freebsd.org> <CAJ5_RoCZKumshQ_17g5qqH2Q2A5s=NzMmThxOurJkGhU=mogyA@mail.gmail.com>
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On 03/15/2017 12:59, Benjamin Kaduk wrote: > Should __FreeBSD_version be bumped, e.g., for out-of-tree filesystems > that have custom vop_advise? No, I don't think so. > On Wed, Mar 15, 2017 at 12:43 PM, Alan Cox <alc@freebsd.org > <mailto:alc@freebsd.org>> wrote: > > Author: alc > Date: Wed Mar 15 17:43:45 2017 > New Revision: 315318 > URL: https://svnweb.freebsd.org/changeset/base/315318 > <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 > <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) > _______________________________________________ > svn-src-all@freebsd.org <mailto:svn-src-all@freebsd.org> mailing list > https://lists.freebsd.org/mailman/listinfo/svn-src-all > <https://lists.freebsd.org/mailman/listinfo/svn-src-all>; > To unsubscribe, send any mail to > "svn-src-all-unsubscribe@freebsd.org > <mailto:svn-src-all-unsubscribe@freebsd.org>" > >
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