From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tom Tromey <tromey@redhat.com>
Subject: Re: linux-next: add utrace tree
Date: Tue, 26 Jan 2010 16:20:22 -0700
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In-Reply-To: <alpine.LFD.2.00.1001251332370.3574@localhost.localdomain> (Linus
	Torvalds's message of "Mon, 25 Jan 2010 13:41:57 -0800 (PST)")
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To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>, Kyle Moffett <kyle@moffetthome.net>, Peter Zijlstra <a.p.zijlstra@chello.nl>, Peter Zijlstra <peterz@infradead.org>, Fr??d??ric Weisbecker <fweisbec@gmail.com>, Oleg Nesterov <oleg@redhat.com>, Steven Rostedt <rostedt@goodmis.org>, LKML <linux-kernel@vger.kernel.org>, Arnaldo Carvalho de Melo <acme@redhat.com>, "Frank Ch. Eigler" <fche@redhat.com>, linux-next@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>, utrace-devel@redhat.com, Thomas Gleixner <tglx@linutronix.de>
List-Id: linux-next.vger.kernel.org

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

Tom> * Support "displaced stepping" in the kernel; I think this would improve
Tom> performance when debugging in non-stop mode.

Linus> Don't we already do that at least on x86?

I don't know.  If it does, and gdb does not yet use that, then that
would be worth changing.

Linus> Or maybe I'm not understanding what displaced stepping means to you.

In non-stop mode (where you can stop one thread but leave the others
running), gdb wants to have the breakpoints always inserted.  So,
something must emulate the displaced instruction.

Tom