Re: [PATCH] Linux Kernel Markers 0.8 for 2.6.17 (with near jump for i386)

[Mathieu Desnoyers <compudj@krystal.dyndns.org>]

* Karim Yaghmour (karim@opersys.com) wrote:
> diffing against an LTT tree ...
> 

Ok, I will do the diff against a vanilla kernel, good point.

> > --- /dev/null
> > +++ b/include/asm-alpha/marker.h
> ...
> > --- /dev/null
> > +++ b/include/asm-arm/marker.h
> ...
> > --- /dev/null
> > +++ b/include/asm-arm26/marker.h
> ...
> ...
> 
> Not sure about the need for asm-foo/marker.h if the file contains no
> code at all. If there's going to be one marker.h per arch, it might
> as well have a purpose. So instead of:
> 
> > --- /dev/null
> > +++ b/include/asm-i386/marker.h
> ...
> > +#define ARCH_HAS_MARK_NEAR_JUMP
> 
> and
> 
> > --- /dev/null
> > +++ b/include/linux/marker.h
> ...
> > +#ifndef ARCH_HAS_MARK_NEAR_JUMP
> ...
> 
> Why not just have asm-foo/marker.h either implement the optimization
> or point to an asm-generic/marker.h which contains the non-optimized
> code. No #ifndefs needed.
> 
Ok, good idea.

> > --- /dev/null
> > +++ b/kernel/Kconfig.marker
> ...
> > +config MARK_SYMBOL
> ...
> > +config MARK_JUMP_CALL
> ...
> > +config MARK_JUMP
> ...
> 
> My understanding of Ingo's input is that he'd rather not have this
> multiple options. Either the markers are active or they aren't.
> So ...
> MARK_ACTIVE ... speaks for itself, enables both the markers and
> the set/disable infrastructure. Markers are enabled in their
> optimized per-architecture implementation.
> 
> MARK_FORCE_DIRECT_CALL ... forces all markers to be non-optimized
> (good for embedded systems where the image is in rom/flash and
> can therefore not have runtime binary modifications.) Maybe this
> should depend on CONFIG_EMBEDDED.
> 
> 

Ok, now only :

CONFIG_MARKERS
and
CONFIG_MARKERS_FORCE_DIRECT_CALL (only appears is EMBEDDED is enabled)

I have rewritted almost everything else, I will post a patch soon (currently
cleaning up). It now supports inline function, unrolled loops and multiple
definitions of the same marker.

Supporting inline functions has proven more important than I first thought
because of gcc 4.0+ optimisations where it takes a static-only function and
inline it automatically in the body of the caller. It removes the symbols of the
inlined function when it does that.

My new approach is a separate .markers section, everything is there.

Mathieu

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