Date: Tue, 21 Apr 2020 13:30:18 -0400 From: Mark Johnston <markj@freebsd.org> To: Eric Joyner <erj@freebsd.org> Cc: freebsd-net@freebsd.org Subject: Re: Issue with epoch_drain_callbacks and unloading iavf(4) [using iflib] Message-ID: <20200421173018.GD86922@raichu> In-Reply-To: <CA%2Bb0zg9bi8Mc0ewnTqadjapHb5V-Mvc1y4c0AgZi08Q_Xy2dcg@mail.gmail.com> References: <CAKdFRZgm43LmjJ9dYDBGM8EV0ePRMLPr4YW_tPELANXQGpqpCA@mail.gmail.com> <CA%2Bb0zg_k=8nMhapa=T=yTcSJcUrrnG=AfQB%2Be0gPcCrgkbWtCQ@mail.gmail.com> <20200331192024.GE97238@raichu> <CA%2Bb0zg9z7srroWLtV_poedghXjCr0GvHv95cu4JzFrRdZoaeWw@mail.gmail.com> <20200406212903.GA55712@raichu> <CA%2Bb0zg-JM1rjO_OPh16sgM3Hm2hbzePNaW5bcxiL9aOpJ_vsOA@mail.gmail.com> <20200407232347.GA5605@raichu> <CA%2Bb0zg9DZys8v--Rwtg1qBkz8XbByehq6vr-xmLtjenNGgRKiQ@mail.gmail.com> <CA%2Bb0zg-swzucfwLZ4kmBKeE-g44L0EqRnft4wR8-_BataDgR%2Bg@mail.gmail.com> <CA%2Bb0zg9bi8Mc0ewnTqadjapHb5V-Mvc1y4c0AgZi08Q_Xy2dcg@mail.gmail.com>
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On Mon, Apr 20, 2020 at 04:39:07PM -0700, Eric Joyner wrote: > On Thu, Apr 9, 2020 at 2:29 PM Eric Joyner <erj@freebsd.org> wrote: > > > On Thu, Apr 9, 2020 at 2:02 PM Eric Joyner <erj@freebsd.org> wrote: > > > >> On Tue, Apr 7, 2020 at 4:24 PM Mark Johnston <markj@freebsd.org> wrote: > >> > >>> I spent some time looking at the core. It looks like we have yet > >>> another problem: the gtaskqueue code won't exit the net epoch if it is > >>> constantly running a net task. Could you please retry with the patches > >>> from before, and this one included? > >>> > >>> diff --git a/sys/kern/subr_gtaskqueue.c b/sys/kern/subr_gtaskqueue.c > >>> index f52f32204644..2b1386a612ee 100644 > >>> --- a/sys/kern/subr_gtaskqueue.c > >>> +++ b/sys/kern/subr_gtaskqueue.c > >>> @@ -345,7 +345,7 @@ gtaskqueue_run_locked(struct gtaskqueue *queue) > >>> struct epoch_tracker et; > >>> struct gtaskqueue_busy tb; > >>> struct gtask *gtask; > >>> - bool in_net_epoch; > >>> + bool in net_epoch; > >>> > >>> KASSERT(queue != NULL, ("tq is NULL")); > >>> TQ_ASSERT_LOCKED(queue); > >>> @@ -361,20 +361,19 @@ gtaskqueue_run_locked(struct gtaskqueue *queue) > >>> TQ_UNLOCK(queue); > >>> > >>> KASSERT(gtask->ta_func != NULL, ("task->ta_func is > >>> NULL")); > >>> - if (!in_net_epoch && TASK_IS_NET(gtask)) { > >>> - in_net_epoch = true; > >>> + if (TASK_IS_NET(gtask)) { > >>> NET_EPOCH_ENTER(et); > >>> - } else if (in_net_epoch && !TASK_IS_NET(gtask)) { > >>> + in_net_epoch = true; > >>> + } > >>> + gtask->ta_func(gtask->ta_context); > >>> + if (in_net_epoch) { > >>> NET_EPOCH_EXIT(et); > >>> in_net_epoch = false; > >>> } > >>> - gtask->ta_func(gtask->ta_context); > >>> > >>> TQ_LOCK(queue); > >>> wakeup(gtask); > >>> } > >>> - if (in_net_epoch) > >>> - NET_EPOCH_EXIT(et); > >>> LIST_REMOVE(&tb, tb_link); > >>> } > >>> > >>> _______________________________________________ > >>> freebsd-net@freebsd.org mailing list > >>> https://lists.freebsd.org/mailman/listinfo/freebsd-net > >>> To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > >>> > >> > >> Yeah, I'll give it a spin and try to get back to you before the end of > >> the week. > >> > >> - Eric > >> > > > > I was able to try it out just now, and it looks this (and all of the other > > patches) finally causes the problem to not appear! I can unload the driver > > while iavf1 is receiving heavy traffic! > > > > - Eric > > > > Hi Mark, > > Are you planning to commit these patches to HEAD? I see the reviews for > D24214 and D24215 are still up, and I don't know if you created a review > for the patch you put in this email chain. Hi Eric, Yes, I'm working on getting those patches reviewed and committed. The patch above was just to verify a theory, we still need a proper solution.
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