mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Duncan Sands <baldrick@wanadoo.fr>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Use of sti in entry.S question
Date: Thu, 22 May 2003 22:48:44 +0200	[thread overview]
Message-ID: <200305222248.44459.baldrick@wanadoo.fr> (raw)
In-Reply-To: <p73ptmb8jwu.fsf@oldwotan.suse.de>

...
> > Is this a mistake or an optimization?  Elsewhere in entry.S, interrupts
> > are turned on before calling schedule:
>
> It's a mistake, but a harmless one. The scheduler turns off interrupts
> soon itself and the instructions it executes before that don't care.
> The only reason it's not recommended to call schedule with interrupts
> off is that the scheduler will turn them on again, usually breaking
> your critical section. In this case it's ok because the next
> instrution is a cli again.

Do you think it's worth pushing this fix?

diff -Nru a/arch/i386/kernel/entry.S b/arch/i386/kernel/entry.S
--- a/arch/i386/kernel/entry.S	Thu May 22 22:45:50 2003
+++ b/arch/i386/kernel/entry.S	Thu May 22 22:45:50 2003
@@ -306,6 +306,7 @@
 	testb $_TIF_NEED_RESCHED, %cl
 	jz work_notifysig
 work_resched:
+	sti
 	call schedule
 	cli				# make sure we don't miss an interrupt
 					# setting need_resched or sigpending


  reply	other threads:[~2003-05-22 20:35 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200305220939.13619.baldrick@wanadoo.fr.suse.lists.linux.kernel>
2003-05-22  8:28 ` Andi Kleen
2003-05-22 20:48   ` Duncan Sands [this message]
2003-05-22  7:39 Duncan Sands

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=200305222248.44459.baldrick@wanadoo.fr \
    --to=baldrick@wanadoo.fr \
    --cc=ak@suse.de \
    --cc=linux-kernel@vger.kernel.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

Powered by JetHome