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From: Andi Kleen <andi@firstfloor.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
	Paul Turner <pjt@google.com>
Subject: Re: Perhaps a side effect regarding NMI returns
Date: Tue, 29 Nov 2011 12:09:47 -0800	[thread overview]
Message-ID: <m2r50qlmgk.fsf@firstfloor.org> (raw)
In-Reply-To: <CA+55aFwehof2kZCENTOFFobWqVvm04BZer6Cc-fQfVvcCE1NVQ@mail.gmail.com> (Linus Torvalds's message of "Mon, 28 Nov 2011 20:53:55 -0800")

Linus Torvalds <torvalds@linux-foundation.org> writes:

Not sure what problem Steven thinks is there. Once you 
switched the stack any nesting is fine.

> I would suggest that the actual NMI handler itself should probably
> never use that paranoid exit at all, and just always use a regular
> iret. Screw scheduling and TIF checks.

The reason I added them originally is to prevent the race of remote
kernel events being delayed for a long time. With Frederic's nohz work
this will be more important in the future. Today it would be eventually
picked up by the regular timer interrupts.

-Andi

-- 
ak@linux.intel.com -- Speaking for myself only

  parent reply	other threads:[~2011-11-29 20:09 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-11-29  4:07 Perhaps a side effect regarding NMI returns Steven Rostedt
2011-11-29  4:53 ` Linus Torvalds
2011-11-29  7:33   ` Paul Turner
2011-11-29 20:09   ` Andi Kleen [this message]
2011-11-29 20:12     ` Linus Torvalds
2011-11-29 20:31       ` Andi Kleen
2011-11-29 20:36         ` Linus Torvalds
2011-11-29 20:58           ` Steven Rostedt
2011-11-29 21:05             ` Linus Torvalds
2011-11-29 21:22               ` Steven Rostedt
2011-11-29 22:14             ` Jason Baron
2011-11-29 22:51               ` Steven Rostedt
2011-11-30 11:56                 ` Peter Zijlstra
2011-11-29 20:35     ` Steven Rostedt
2011-11-29 20:44       ` Linus Torvalds
2011-12-07 16:36         ` Steven Rostedt
2011-12-07 16:44           ` Linus Torvalds
2011-12-07 17:31             ` Steven Rostedt
2011-12-07 17:48               ` Linus Torvalds
2011-12-07 17:51           ` Andi Kleen
2012-01-08  8:55         ` [tip:perf/core] x86: Do not schedule while still in NMI context tip-bot for Linus Torvalds
2011-11-29 21:28       ` Perhaps a side effect regarding NMI returns Andi Kleen

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