From: Frederic Weisbecker <fweisbec@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [PATCH 1/3] x86/sched/context_tracking: Call new schedule_preempt_user() from entry_64.S
Date: Sat, 11 May 2013 03:36:30 +0200 [thread overview]
Message-ID: <20130511013629.GE13340@somewhere> (raw)
In-Reply-To: <20130510211825.341015861@goodmis.org>
On Fri, May 10, 2013 at 05:12:26PM -0400, Steven Rostedt wrote:
> +/*
> + * This is a entry point to the scheduler() just before going
> + * back to user space. This is called with irqs disabled
> + * which prevents races with the CONTEXT_TRACKING updates.
> + */
> +asmlinkage void __sched schedule_preempt_user(void)
> +{
> + enum ctx_state prev_state;
> +
> + prev_state = exception_enter();
> +
> + local_irq_enable();
> + __schedule();
> + local_irq_disable();
> +
> + exception_exit(prev_state);
So since it's only ever called right before resuming to userspace and after
the user_exit() call from the end of the syscall/exception/irq code,
you can use user_enter()/user_exit() directly.
I'm also wondering if this assumption that irqs are disabled by the time
we do user preemption is x86-centric or not. May be we can wait for complains
from those who'll port it...
next prev parent reply other threads:[~2013-05-11 1:36 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-10 21:12 [PATCH 0/3] nohz: Some fixes and updates Steven Rostedt
2013-05-10 21:12 ` [PATCH 1/3] x86/sched/context_tracking: Call new schedule_preempt_user() from entry_64.S Steven Rostedt
2013-05-11 1:36 ` Frederic Weisbecker [this message]
2013-05-13 9:56 ` Li Zhong
2013-05-13 15:03 ` Steven Rostedt
2013-05-14 9:44 ` Li Zhong
2013-05-14 14:13 ` Frederic Weisbecker
2013-05-15 1:38 ` Li Zhong
2013-05-10 21:12 ` [PATCH 2/3] nohz: Disable LOCKUP_DETECTOR when NO_HZ_FULL is enabled Steven Rostedt
2013-05-10 21:12 ` [PATCH 3/3] nohz: Warn if the machine can not perform nohz_full Steven Rostedt
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=20130511013629.GE13340@somewhere \
--to=fweisbec@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=paulmck@us.ibm.com \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/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