From: Ingo Molnar <mingo@elte.hu>
To: "David S. Miller" <davem@davemloft.net>
Cc: mgross@linux.intel.com, rostedt@goodmis.org,
linux-kernel@vger.kernel.org, Mark_H_Johnson@raytheon.com
Subject: Re: queue_work from interrupt Real time preemption2.6.11-rc2-RT-V0.7.37-03
Date: Thu, 17 Feb 2005 08:52:12 +0100 [thread overview]
Message-ID: <20050217075212.GA21621@elte.hu> (raw)
In-Reply-To: <20050216081143.50d0a9d6.davem@davemloft.net>
* David S. Miller <davem@davemloft.net> wrote:
> > Maybe the networking
> > stack would break if we allowed the TIMER softirq (thread) to preempt
> > the NET softirq (threads) (and vice versa)?
>
> The major assumption is that softirq's run indivisibly per-cpu.
> Otherwise the per-cpu queues of RX and TX packet work would get
> corrupted.
as long as it stays on a single CPU, could we allow softirq contexts to
preempt each other? I.e. we'd keep the per-CPU assumption (that is fair
and needed for performance anyway), but we'd allow NET_TX to preempt
NET_RX and vice versa. Would this corrupt the rx/tx queues? (i suspect
it would.)
(anyway, by adding an explicit no-preempt section around the 'take
current rx queue private, then process it' on PREEMPT_RT it could be
made safe. I'm wondering whether there are any other deeper assumptions
about atomic separation of softirq contexts.)
Ingo
next prev parent reply other threads:[~2005-02-17 7:52 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-14 20:40 queue_work from interrupt Real time preemption2.6.11-rc2-RT-V0.7.37-03 Mark Gross
2005-02-14 21:24 ` Steven Rostedt
2005-02-14 22:29 ` Mark Gross
2005-02-15 10:41 ` Ingo Molnar
2005-02-15 18:06 ` Mark Gross
2005-02-16 5:16 ` Ingo Molnar
2005-02-16 16:11 ` David S. Miller
2005-02-16 17:59 ` George Anzinger
2005-02-16 22:55 ` Mark Gross
2005-02-16 18:02 ` Steven Rostedt
2005-02-17 7:57 ` Ingo Molnar
2005-02-17 15:13 ` Steven Rostedt
2005-02-17 7:52 ` Ingo Molnar [this message]
2005-02-17 14:57 ` Steven Rostedt
2005-02-17 16:14 ` Mark Gross
2005-03-29 8:57 ` Ingo Molnar
2005-03-31 18:41 ` Mark Gross
2005-04-01 5:55 ` Ingo Molnar
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=20050217075212.GA21621@elte.hu \
--to=mingo@elte.hu \
--cc=Mark_H_Johnson@raytheon.com \
--cc=davem@davemloft.net \
--cc=linux-kernel@vger.kernel.org \
--cc=mgross@linux.intel.com \
--cc=rostedt@goodmis.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 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.