From: Eric Dumazet <edumazet@google.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josef Griebichler <griebichler.josef@gmx.at>,
Jesper Dangaard Brouer <jbrouer@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Mauro Carvalho Chehab <mchehab@s-opensource.com>,
Alan Stern <stern@rowland.harvard.edu>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
USB list <linux-usb@vger.kernel.org>,
Rik van Riel <riel@redhat.com>, Paolo Abeni <pabeni@redhat.com>,
Hannes Frederic Sowa <hannes@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
netdev <netdev@vger.kernel.org>, Jonathan Corbet <corbet@lwn.net>,
LMML <linux-media@vger.kernel.org>,
David Miller <davem@davemloft.net>
Subject: Re: Re: dvb usb issues since kernel 4.9
Date: Tue, 9 Jan 2018 09:57:24 -0800 [thread overview]
Message-ID: <CANn89iLo9WsFq-cvL63zD6hOXFRs97hDifksNsAHTegNQqXzZw@mail.gmail.com> (raw)
In-Reply-To: <CA+55aFzcoNEpnRp0R3fLYQKdfzS5mLj3z_v=1A1NfyrybQ__4A@mail.gmail.com>
On Tue, Jan 9, 2018 at 9:48 AM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
> On Tue, Jan 9, 2018 at 9:27 AM, Eric Dumazet <edumazet@google.com> wrote:
>>
>> So yes, commit 4cd13c21b207 ("softirq: Let ksoftirqd do its job") has
>> shown up multiple times in various 'regressions'
>> simply because it could surface the problem more often.
>> But even if you revert it, you can still make the faulty
>> driver/subsystem misbehave by adding more stress to the cpu handling
>> the IRQ.
>
> ..but that's always true. People sometimes live on the edge - often by
> design (ie hardware has been designed/selected to be the crappiest
> possible that still work).
>
> That doesn't change anything. A patch that takes "bad things can
> happen" to "bad things DO happen" is a bad patch.
I was expecting that people could get a chance to fix the root cause,
instead of trying to keep status quo.
Strangely, it took 18 months for someone to complain enough and
'bisect to this commit'
Your patch considers TASKLET_SOFTIRQ being a candidate for 'immediate
handling', but TCP Small queues heavily use TASKLET,
so as far as I am concerned a revert would have the same effect.
next prev parent reply other threads:[~2018-01-09 17:57 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <trinity-35b3a044-b548-4a31-9646-ed9bc83e6846-1513505978471@3c-app-gmx-bs03>
[not found] ` <20171217120634.pmmuhdqyqmbkxrvl@gofer.mess.org>
[not found] ` <20171217112738.4f3a4f9b@recife.lan>
[not found] ` <trinity-1fa14556-8596-44b1-95cb-b8919d94d2d4-1515251056328@3c-app-gmx-bs15>
2018-01-06 19:54 ` dvb usb issues since kernel 4.9 Mauro Carvalho Chehab
2018-01-06 21:07 ` Aw: " Josef Griebichler
2018-01-06 21:44 ` Alan Stern
2018-01-07 11:03 ` Mauro Carvalho Chehab
2018-01-07 15:41 ` Alan Stern
[not found] ` <Pine.LNX.4.44L0.1801071010540.13425-100000-pYrvlCTfrz9XsRXLowluHWD2FQJk+8+b@public.gmane.org>
2018-01-07 17:01 ` Aw: " Josef Griebichler
2018-01-08 9:43 ` Mauro Carvalho Chehab
2018-01-08 16:10 ` Alan Stern
2018-01-08 16:26 ` Aw: " Josef Griebichler
2018-01-08 16:31 ` Alan Stern
2018-01-08 17:15 ` Aw: " Josef Griebichler
2018-01-08 17:35 ` Alan Stern
2018-01-08 20:40 ` Jesper Dangaard Brouer
2018-01-08 21:31 ` Jesper Dangaard Brouer
2018-01-08 21:44 ` Peter Zijlstra
2018-01-08 22:16 ` Jesper Dangaard Brouer
2018-01-09 16:51 ` Aw: " Josef Griebichler
2018-01-09 17:27 ` Eric Dumazet
2018-01-09 17:48 ` Linus Torvalds
2018-01-09 17:57 ` Eric Dumazet [this message]
2018-01-09 18:58 ` Linus Torvalds
2018-01-09 21:48 ` Eric Dumazet
2018-01-10 9:45 ` Jesper Dangaard Brouer
2018-01-12 21:13 ` Mauro Carvalho Chehab
2018-01-12 21:48 ` Eric Dumazet
2018-01-13 9:09 ` Mauro Carvalho Chehab
2018-01-13 10:46 ` Mauro Carvalho Chehab
2018-01-07 21:23 ` Linus Torvalds
2018-01-08 10:02 ` Mauro Carvalho Chehab
2018-01-08 11:59 ` Jesper Dangaard Brouer
2018-01-08 12:53 ` Mauro Carvalho Chehab
2018-01-08 16:25 ` Alan Stern
2018-01-08 17:55 ` Ingo Molnar
2018-01-08 18:32 ` Linus Torvalds
2018-01-08 19:15 ` Alan Stern
2018-01-08 19:51 ` Linus Torvalds
2018-01-09 17:42 ` Mauro Carvalho Chehab
2018-01-09 17:55 ` Linus Torvalds
2018-01-09 21:26 ` Jesper Dangaard Brouer
2018-01-10 3:02 ` Mike Galbraith
2018-07-17 11:54 ` Hanna Hawa
2018-07-17 17:09 ` Linus Torvalds
2018-07-17 18:07 ` Hanna Hawa
2018-07-17 22:21 ` Mauro Carvalho Chehab
2018-01-26 14:17 ` Mauro Carvalho Chehab
2018-01-26 19:37 ` Mauro Carvalho Chehab
2018-01-29 13:51 ` Mauro Carvalho Chehab
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=CANn89iLo9WsFq-cvL63zD6hOXFRs97hDifksNsAHTegNQqXzZw@mail.gmail.com \
--to=edumazet@google.com \
--cc=corbet@lwn.net \
--cc=davem@davemloft.net \
--cc=gregkh@linuxfoundation.org \
--cc=griebichler.josef@gmx.at \
--cc=hannes@redhat.com \
--cc=jbrouer@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=mchehab@s-opensource.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=stern@rowland.harvard.edu \
--cc=torvalds@linux-foundation.org \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).