From: Ingo Molnar <mingo@elte.hu>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] little schedule() cleanup: use cached current value
Date: Tue, 9 Nov 2004 13:45:53 +0100 [thread overview]
Message-ID: <20041109124553.GA25663@elte.hu> (raw)
In-Reply-To: <4190ADD7.CE7EFB7C@tv-sign.ru>
* Oleg Nesterov <oleg@tv-sign.ru> wrote:
> @@ -2636,7 +2636,7 @@ switch_tasks:
> } else
> spin_unlock_irq(&rq->lock);
>
> - reacquire_kernel_lock(current);
> + reacquire_kernel_lock(next);
> preempt_enable_no_resched();
> if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
> goto need_resched;
nack. We switch the kernel stack in switch_to() so 'next' here is the
old task we switched to before we went off the CPU. The value of 'next'
doesnt get carried over a context-switch. (we do carry 'prev' over via
assembly trickery because we need it, but not 'next'.) This change would
most likely result in rare, hard-to-track-down BKL-related crashes all
around the place.
the other bits are OK, please resend them.
Ingo
next prev parent reply other threads:[~2004-11-09 11:44 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-11-09 11:45 Oleg Nesterov
2004-11-09 12:45 ` Ingo Molnar [this message]
2004-11-09 14:27 ` Oleg Nesterov
2004-11-09 15:32 ` 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=20041109124553.GA25663@elte.hu \
--to=mingo@elte.hu \
--cc=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@tv-sign.ru \
/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
all inboxes | Powered by JetHome®