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Date: Thu, 21 Sep 2006 22:01:19 -0400 From: Mathieu Desnoyers <compudj@...stal.dyndns.org> To: Jeremy Fitzhardinge <jeremy@...p.org> Cc: Martin Bligh <mbligh@...gle.com>, "Frank Ch. Eigler" <fche@...hat.com>, Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>, prasanna@...ibm.com, Andrew Morton <akpm@...l.org>, Ingo Molnar <mingo@...e.hu>, Paul Mundt <lethal@...ux-sh.org>, linux-kernel <linux-kernel@...r.kernel.org>, Jes Sorensen <jes@....com>, Tom Zanussi <zanussi@...ibm.com>, Richard J Moore <richardj_moore@...ibm.com>, Michel Dagenais <michel.dagenais@...ymtl.ca>, Christoph Hellwig <hch@...radead.org>, Greg Kroah-Hartman <gregkh@...e.de>, Thomas Gleixner <tglx@...utronix.de>, William Cohen <wcohen@...hat.com>, ltt-dev@...fik.org, systemtap@...rces.redhat.com, Alan Cox <alan@...rguk.ukuu.org.uk> Subject: Re: [PATCH] Linux Kernel Markers 0.7 for 2.6.17 (with type checking!) * Jeremy Fitzhardinge (jeremy@...p.org) wrote: > Mathieu Desnoyers wrote: > >+#ifdef CONFIG_MARK_SYMBOL > >+#define MARK_SYM(name) \ > >+ do { \ > >+ __label__ here; \ > >+ here: asm volatile \ > >+ (MARK_KPROBE_PREFIX#name " = %0" : : "m" (*&&here)); > >\ > >+ } while(0) > >+#else > >+#define MARK_SYM(name) > >+#endif > > BTW, this won't work if you put the MARK_SYM in a loop which gcc > unrolls; you'll only get the mark in the last unrolled iteration > (because the symbol assignments will override each other). > > Do make this work properly, you really need to put the mark entries into > a separate section, so that if gcc duplicates the code, you get > duplicated markers too. > Good point, I will change it to : #define MARK_SYM(name) \ do { \ __label__ here; \ volatile static void *__mark_kprobe_##name \ asm (MARK_CALL_PREFIX#name) \ __attribute__((unused)) = &&here; \ here: \ do { } while(0); \ } while(0) Which fixes the problem. Some tests showed me that the compiler does not unroll an otherwise unrolled loop when this specific macro is called. (test done with -funroll-all-loops). Regards, Mathieu OpenPGP public key: http://krystal.dyndns.org:8080/key/compudj.gpg Key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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