Date: Mon, 20 Apr 2020 16:39:07 -0700 From: Eric Joyner <erj@freebsd.org> To: Mark Johnston <markj@freebsd.org> Cc: Hans Petter Selasky <hps@selasky.org>, freebsd-net@freebsd.org, shurd <shurd@freebsd.org>, John Baldwin <jhb@freebsd.org>, Drew Gallatin <gallatin@netflix.com> Subject: Re: Issue with epoch_drain_callbacks and unloading iavf(4) [using iflib] Message-ID: <CA%2Bb0zg9bi8Mc0ewnTqadjapHb5V-Mvc1y4c0AgZi08Q_Xy2dcg@mail.gmail.com> In-Reply-To: <CA%2Bb0zg-swzucfwLZ4kmBKeE-g44L0EqRnft4wR8-_BataDgR%2Bg@mail.gmail.com> References: <CA%2Bb0zg809EGMS1Ngr38BSb1yNpDqxbCnAv9eC%2BcDwbMQ5t%2BqXQ@mail.gmail.com> <20200212222219.GE83892@raichu> <CAKdFRZjdiz_axuweksNUHis7jPKXHqOmhQg%2BQWzpVnsKY%2Bcrmg@mail.gmail.com> <20200328225150.GA82767@raichu> <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>
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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. - Eric
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