From: Andrea Arcangeli <andrea@novell.com>
To: Jens Axboe <axboe@suse.de>
Cc: Lee Revell <rlrevell@joe-job.com>, Ingo Molnar <mingo@elte.hu>,
Chris Wedgwood <cw@f00f.org>,
Arjan van de Ven <arjanv@redhat.com>,
Hugh Dickins <hugh@veritas.com>,
"Martin J. Bligh" <mbligh@aracnet.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>
Subject: Re: [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option
Date: Mon, 13 Sep 2004 12:31:58 +0200 [thread overview]
Message-ID: <20040913103158.GA17625@dualathlon.random> (raw)
In-Reply-To: <20040913073259.GF2326@suse.de>
On Mon, Sep 13, 2004 at 09:32:59AM +0200, Jens Axboe wrote:
> completion from hardirq context, SCSI is the exception since it does it
> defers the completion to softirq context.
which btw doesn't really make much difference at all to run it in irq
context with irq enabled since it'll run from irq context anyways and
you'll still depend on nested hardirqs to avoid huge latencies from
softirq handlers (the most difference between softirq and hardirq with
irq enabled happens if you can use spin_lock_bh instead of spin_lock_irq
in the critical sections to protect against other cpus).
softirq runs inside an hardirq in all common cases, so a softirq is
still an hardirq and to allow other hardirq to run you need nested
interrupts in the hardware (which again explains why it's a bad idea to
forbid nesting by design, and really I don't buy the slowdown argument,
enter/exit kernel would happen anyways, it's just the pipeline will be
stalled once and the cache may be trashed a bit, but irqs have not an
huge memory footprint anyways).
next prev parent reply other threads:[~2004-09-13 10:31 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 23:25 [PATCH 1/3] Separate IRQ-stacks from 4K-stacks option Chris Wedgwood
2004-09-09 23:55 ` Brian Gerst
2004-09-09 23:59 ` Chris Wedgwood
2004-09-10 6:40 ` Arjan van de Ven
2004-09-10 6:45 ` Chris Wedgwood
2004-09-10 6:52 ` Arjan van de Ven
2004-09-10 7:15 ` Chris Wedgwood
2004-09-10 7:21 ` Arjan van de Ven
2004-09-10 7:23 ` Chris Wedgwood
2004-09-10 7:35 ` Arjan van de Ven
2004-09-10 9:12 ` Alan Cox
2004-09-10 9:14 ` Alan Cox
2004-09-10 10:27 ` Russell King
2004-09-10 14:30 ` Martin J. Bligh
2004-09-10 15:06 ` Chris Wedgwood
2004-09-10 15:07 ` Hugh Dickins
2004-09-10 15:12 ` Alan Cox
2004-09-10 15:15 ` Arjan van de Ven
2004-09-10 15:28 ` Andrea Arcangeli
2004-09-10 15:09 ` Alan Cox
2004-09-10 15:34 ` Arjan van de Ven
2004-09-12 14:17 ` Andrea Arcangeli
2004-09-12 15:03 ` Martin J. Bligh
2004-09-12 15:45 ` Zwane Mwaikambo
2004-09-12 16:00 ` Martin J. Bligh
2004-10-20 16:27 ` Lee Revell
2004-10-21 15:18 ` Zwane Mwaikambo
2004-09-12 19:18 ` Lee Revell
2004-09-12 19:25 ` Chris Wedgwood
2004-09-12 19:35 ` Ingo Molnar
2004-09-12 19:40 ` Chris Wedgwood
2004-09-12 19:44 ` Ingo Molnar
2004-09-12 20:33 ` Andrea Arcangeli
2004-09-12 21:36 ` Lee Revell
2004-09-12 22:07 ` Andrea Arcangeli
2004-09-12 22:25 ` Lee Revell
2004-09-13 6:16 ` Ingo Molnar
2004-09-13 7:27 ` Lee Revell
2004-09-15 19:43 ` Bill Davidsen
2004-09-15 19:51 ` Andrea Arcangeli
2004-09-15 20:00 ` Ingo Molnar
2004-09-15 20:39 ` Lee Revell
2004-10-20 17:50 ` Timothy Miller
2004-09-13 7:32 ` Jens Axboe
2004-09-13 10:31 ` Andrea Arcangeli [this message]
2004-09-13 10:34 ` Arjan van de Ven
2004-09-13 12:30 ` Jens Axboe
2004-10-20 17:46 ` Timothy Miller
2004-09-13 10:51 ` Alan Cox
2004-09-13 20:26 ` Bill Davidsen
2004-09-14 5:20 ` Lee Revell
2004-10-20 15:46 ` Timothy Miller
2004-10-20 15:35 ` Arjan van de Ven
2004-10-20 16:39 ` Lee Revell
2004-10-20 16:50 ` Andrea Arcangeli
2004-10-20 16:55 ` Lee Revell
2004-10-20 17:08 ` Andrea Arcangeli
2004-10-20 17:15 ` Lee Revell
2004-10-20 17:34 ` Andrea Arcangeli
2004-10-20 17:58 ` Timothy Miller
2004-10-20 17:55 ` Lee Revell
2004-10-20 18:25 ` Timothy Miller
2004-10-20 18:28 ` Lee Revell
2004-10-20 18:51 ` Alan Cox
2004-10-20 23:19 ` Lee Revell
2004-09-10 15:16 ` Martin J. Bligh
2004-10-20 15:43 ` Timothy Miller
2004-10-20 15:35 ` Arjan van de Ven
2004-09-10 15:58 ` Alexander E. Patrakov
2004-09-10 16:19 ` Nathan Bryant
2004-09-10 17:54 ` Martin J. Bligh
2004-09-10 17:54 ` Bill Davidsen
2004-09-10 9:27 ` Alan Cox
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=20040913103158.GA17625@dualathlon.random \
--to=andrea@novell.com \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=arjanv@redhat.com \
--cc=axboe@suse.de \
--cc=cw@f00f.org \
--cc=hch@infradead.org \
--cc=hugh@veritas.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mbligh@aracnet.com \
--cc=mingo@elte.hu \
--cc=rlrevell@joe-job.com \
/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.