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Re: [PATCH] Linux Kernel Markers 0.11 for 2.6.17
- From: Mathieu Desnoyers <compudj at krystal dot dyndns dot org>
- To: Jeremy Fitzhardinge <jeremy at goop dot org>
- Cc: Martin Bligh <mbligh at google dot com>, "Frank Ch. Eigler" <fche at redhat dot com>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, prasanna at in dot ibm dot com, Andrew Morton <akpm at osdl dot org>, Ingo Molnar <mingo at elte dot hu>, Paul Mundt <lethal at linux-sh dot org>, linux-kernel <linux-kernel at vger dot kernel dot org>, Jes Sorensen <jes at sgi dot com>, Tom Zanussi <zanussi at us dot ibm dot com>, Richard J Moore <richardj_moore at uk dot ibm dot com>, Michel Dagenais <michel dot dagenais at polymtl dot ca>, Christoph Hellwig <hch at infradead dot org>, Greg Kroah-Hartman <gregkh at suse dot de>, Thomas Gleixner <tglx at linutronix dot de>, William Cohen <wcohen at redhat dot com>, ltt-dev at shafik dot org, systemtap at sources dot redhat dot com, Alan Cox <alan at lxorguk dot ukuu dot org dot uk>, Karim Yaghmour <karim at opersys dot com>, Pavel Machek <pavel at suse dot cz>, Joe Perches <joe at perches dot com>, "Randy.Dunlap" <rdunlap at xenotime dot net>, "Jose R. Santos" <jrs at us dot ibm dot com>
- Date: Mon, 25 Sep 2006 17:32:07 -0400
- Subject: Re: [PATCH] Linux Kernel Markers 0.11 for 2.6.17
- References: <20060925151028.GA14695@Krystal> <45181CE9.1080204@goop.org> <20060925201036.GB13049@Krystal> <45183B20.2080907@goop.org> <20060925203502.GA3770@Krystal> <20060925204701.GB3770@Krystal> <45184885.8020807@goop.org>
* Jeremy Fitzhardinge (jeremy@goop.org) wrote:
> Mathieu Desnoyers wrote:
> >Better idea : we could put a read/write dependency on a memory location.
> >
>
> Yes, that works well. And it needn't even exist:
>
> extern int __marker_sequencer; /* doesn't exist, never
> referenced */
>
> asm volatile("first asm" : "+m" (__marker_sequencer));
>
> asm volatile("second asm" : "+m" (__marker_sequencer));
>
> This keeps the asms ordered with respect to each other (and prevents to
> independent markers from being intermingled), but it doesn't prevent
> them from being re-ordered with respect to other code.
>
I will declare the pointers around the jmp instruction directly in assembly : I
wouldn't want gcc to put some other code there by mistake.
I will use the "name" variable, as it is already there.
A new version coming soon...
Thank you very much!
Mathieu
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