Date: Sun, 22 Apr 2018 16:28:55 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Tijl Coosemans <tijl@FreeBSD.org> Cc: jeff@FreeBSD.org, "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: Re: i386 hangs during halt "vnodes remaining... 0 time out" Message-ID: <20180422132855.GU6887@kib.kiev.ua> In-Reply-To: <20180422151500.1608af96@kalimero.tijl.coosemans.org> References: <YQBPR0101MB1042BF37F603335C9CE6346BDD8B0@YQBPR0101MB1042.CANPRD01.PROD.OUTLOOK.COM> <20180421234934.10d7dfab@kalimero.tijl.coosemans.org> <20180422120521.GS6887@kib.kiev.ua> <20180422151500.1608af96@kalimero.tijl.coosemans.org>
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On Sun, Apr 22, 2018 at 03:15:00PM +0200, Tijl Coosemans wrote: > On Sun, 22 Apr 2018 15:05:21 +0300 Konstantin Belousov <kostikbel@gmail.com> wrote: > > On Sat, Apr 21, 2018 at 11:49:34PM +0200, Tijl Coosemans wrote: > >> On Sat, 21 Apr 2018 21:09:09 +0000 Rick Macklem <rmacklem@uoguelph.ca> wrote: > >>> With a recent head/current kernel (doesn't happen when running a Dec. > >>> 2017 one), when I do a halt, it gets as far as: > >>> > >>> vnodes remaining... 0 time out > >>> > >>> and that's it (the time out appears several seconds after the first "0"). > >>> With a Dec. 2017 kernel there would be several "0"s printed. > >>> It appears that it is stuck in the first iteration of the sched_sync() > >>> loop after it is no longer in SYNCER_RUNNING state. > >>> > >>> Any ideas? rick > >> > >> See https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=227404 > >> I have a patch (attached) but haven't been able to test it yet. > >> > >> Index: sys/kern/vfs_bio.c > >> =================================================================== > >> --- sys/kern/vfs_bio.c (revision 332165) > >> +++ sys/kern/vfs_bio.c (working copy) > >> @@ -791,9 +791,12 @@ bufspace_daemon(void *arg) > >> { > >> struct bufdomain *bd; > >> > >> + EVENTHANDLER_REGISTER(shutdown_pre_sync, kthread_shutdown, curthread, > >> + SHUTDOWN_PRI_LAST); > >> + > >> bd = arg; > >> for (;;) { > >> - kproc_suspend_check(curproc); > >> + kthread_suspend_check(); > >> > >> /* > >> * Free buffers from the clean queue until we meet our > >> @@ -3357,7 +3360,7 @@ buf_daemon() > >> /* > >> * This process needs to be suspended prior to shutdown sync. > >> */ > >> - EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, bufdaemonproc, > >> + EVENTHANDLER_REGISTER(shutdown_pre_sync, kthread_shutdown, curthread, > >> SHUTDOWN_PRI_LAST); > >> > >> /* > >> @@ -3381,7 +3384,7 @@ buf_daemon() > >> bd_request = 0; > >> mtx_unlock(&bdlock); > >> > >> - kproc_suspend_check(bufdaemonproc); > >> + kthread_suspend_check(); > >> > >> /* > >> * Save speedupreq for this pass and reset to capture new > > This looks fine. > > Thanks for the review. There's just one concern I have. With this patch > the bufspace_daemon threads appear to shutdown after the buf_daemon and > after the syncer because the event handlers are registered later. Are > there any dependencies between these processes that require the bufspace > threads to be stopped earlier? I think for correctness bufdaemon must stop after the syncer, since syncer operation can cause a situation where bufdaemon help is needed to proceed. Other than this, the stop order is irrelevant, because after syncer finished, there should be no any further filesystem activity.home | help
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