From: Jakub Kicinski <kuba@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
netdev@vger.kernel.org, Juri Lelli <juri.lelli@redhat.com>,
linux-rt-users <linux-rt-users@vger.kernel.org>,
Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
sassmann@redhat.com, "David S. Miller" <davem@davemloft.net>,
stable-rt@vger.kernel.org
Subject: Re: [PATCH net-next] net: Treat __napi_schedule_irqoff() as __napi_schedule() on PREEMPT_RT
Date: Fri, 14 May 2021 13:38:15 -0700 [thread overview]
Message-ID: <20210514133815.6a698aeb@kicinski-fedora-PC1C0HJN> (raw)
In-Reply-To: <87v97l2hrp.ffs@nanos.tec.linutronix.de>
On Fri, 14 May 2021 22:16:10 +0200 Thomas Gleixner wrote:
> On Fri, May 14 2021 at 11:56, Jakub Kicinski wrote:
> > On Thu, 13 May 2021 00:28:02 +0200 Thomas Gleixner wrote:
> >> Blame me for that decision.
> >>
> >> No matter which variant we end up with, this needs to go into all stable
> >> RT kernels ASAP.
> >
> > Mumble mumble. I thought we concluded that drivers used on RT can be
> > fixed, we've already done it for a couple drivers (by which I mean two).
> > If all the IRQ handler is doing is scheduling NAPI (which it is for
> > modern NICs) - IRQF_NO_THREAD seems like the right option.
>
> Yes. That works, but there are a bunch which do more than that IIRC.
>
> > Is there any driver you care about that we can convert to using
> > IRQF_NO_THREAD so we can have new drivers to "do the right thing"
> > while the old ones depend on this workaround for now?
>
> The start of this thread was about i40e_msix_clean_rings() which
> probably falls under the IRQF_NO_THREAD category, but I'm sure that
> there are others. So I chose the safe way for RT for now.
Sounds reasonable. I'll send a patch with a new helper and convert
an example driver I'm sure falls into the "napi_schedule(); return;"
category. I just want to make sure "the right thing to do" is
accessible for people writing new drivers.
next prev parent reply other threads:[~2021-05-14 20:38 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 6:09 [RT] Question about i40e threaded irq Juri Lelli
2021-05-11 6:24 ` Stefan Assmann
2021-05-11 7:46 ` Thomas Gleixner
2021-05-12 21:43 ` [PATCH net-next] net: Treat __napi_schedule_irqoff() as __napi_schedule() on PREEMPT_RT Sebastian Andrzej Siewior
2021-05-12 22:28 ` Thomas Gleixner
2021-05-13 0:50 ` Steven Rostedt
2021-05-13 16:43 ` Steven Rostedt
2021-05-14 12:11 ` Thomas Gleixner
2021-05-14 18:56 ` Jakub Kicinski
2021-05-14 19:44 ` Alison Chaiken
2021-05-14 21:53 ` Thomas Gleixner
2021-05-14 20:16 ` Thomas Gleixner
2021-05-14 20:38 ` Jakub Kicinski [this message]
2021-05-13 5:12 ` Juri Lelli
2021-05-13 20:20 ` patchwork-bot+netdevbpf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210514133815.6a698aeb@kicinski-fedora-PC1C0HJN \
--to=kuba@kernel.org \
--cc=bigeasy@linutronix.de \
--cc=davem@davemloft.net \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=rostedt@goodmis.org \
--cc=sassmann@redhat.com \
--cc=stable-rt@vger.kernel.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.