On Friday, November 19, 2010 4:31:44 pm Attilio Rao wrote: > 2010/11/19 John Baldwin <j...@freebsd.org>: > > On Friday, November 19, 2010 4:09:28 pm Jung-uk Kim wrote: > >> On Friday 19 November 2010 02:43 pm, Attilio Rao wrote: > >> > Author: attilio > >> > Date: Fri Nov 19 19:43:56 2010 > >> > New Revision: 215544 > >> > URL: http://svn.freebsd.org/changeset/base/215544 > >> > > >> > Log: > >> > Scan the list in reverse order for the shutdown handlers of > >> > loaded modules. This way, when there is a dependency between two > >> > modules, the handler of the latter probed runs first. > >> > > >> > This is a similar approach as the modules are unloaded in the > >> > same linkerfile. > >> > > >> > Sponsored by: Sandvine Incorporated > >> > Submitted by: Nima Misaghian <nmisaghian at sandvine dot com> > >> > MFC after: 1 week > >> > >> Hmm... It is not directly related but I was thinking about doing > >> similar things for sys/kern/subr_bus.c. What do you think about the > >> attached patch? > > > > Hmm, the patches for suspend and resume that I had for this took the > > opposite > > order, they did suspend in forward order, but resume in backwards order. > > Like so: > > > > --- //depot/vendor/freebsd/src/sys/kern/subr_bus.c 2010-11-17 > > 22:30:24.000000000 0000 > > +++ //depot/user/jhb/acpipci/kern/subr_bus.c 2010-11-19 > > 17:19:02.000000000 00 > > @@ -3426,9 +3429,9 @@ > > TAILQ_FOREACH(child, &dev->children, link) { > > error = DEVICE_SUSPEND(child); > > if (error) { > > - for (child2 = TAILQ_FIRST(&dev->children); > > - child2 && child2 != child; > > - child2 = TAILQ_NEXT(child2, link)) > > + for (child2 = TAILQ_PREV(child, device_list, link); > > + child2 != NULL; > > + child2 = TAILQ_PREV(child2, device_list, link)) > > DEVICE_RESUME(child2); > > return (error); > > } > > @@ -3447,7 +3450,7 @@ > > { > > device_t child; > > > > - TAILQ_FOREACH(child, &dev->children, link) { > > + TAILQ_FOREACH_REVERSE(child, &dev->children, device_list, link) { > > DEVICE_RESUME(child); > > /* if resume fails, there's nothing we can usefully do... */ > > } > > > > (Likely mangled whitespace.) > > > > I couldn't convince myself which order was "more" correct for suspend and > > resume. > > Considering loading in starting point, I think suspend should go in > reverse logic and resume in the same module load logic. > So that dependent modules are suspended first and resumed after. > Don't you agree?
These are devices, and the ordering here is the order of sibling devices on a given bus. That is, if you have a PCI bus with two em interfaces, does it really matter if em0 suspends before em1 vs after em1? I think it actually doesn't matter. The passes from the multipass boot probe might make some sense to order on. However, I don't think the order of siblings on a bus is meaningful for suspend and resume (which is why I've never committed the above patches). Specifically, there is no dependency relationship between siblings on a bus. Certain buses may in fact have a dependency order of sorts (vgapci0 comes to mind), but those buses should manage that. There is no generic dependency between siblings that should be encoded into subr_bus.c -- John Baldwin _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
