Xen devel - Oct 2008 - [RFC][PATCH] add tlsf option for xmalloc

This patch is a first step for replacing the current xmalloc
engine with a tlsf-based engine.  The first patch simply adds
Nitin Gupta''s current tlsf-kmod files to Xen and the second
modifies them (and xmalloc) to adapt them to work with Xen.

The tlsf engine can be turned on (and then overrides the xmalloc
engine) with a Xen boot option of "tlsf".  This defaults to off,
so the patch should have no effect without the boot option.

Note that this is compile-tested but not run tested yet.  I
thought I''d get feedback on the approach before I get much
further.

Thanks,
Dan


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On 15/10/08 18:47, "Dan Magenheimer"
<dan.magenheimer@oracle.com> wrote:
> Note that this is compile-tested but not run tested yet.  I
> thought I''d get feedback on the approach before I get much
> further.
The approach is fine as far as I''m concerned. It should just replace
the
existing xmalloc.c of course: no point in keeping the old one around.
Therefore may as well put the whole implementation in xmalloc.c, or call it
xmalloc_tlsf.c if you''re really keen to keep the name of the algorithm
in
the file name (in which case xmalloc.c should be entirely deleted; or
perhaps temporarily make it a build option which .c file gets built if
really worried that the new xmalloc implementation may have subtle bugs and
we''d like to be able to revert for testing).

Structure definitions and the like which are private to TLSF should live at
the top of the .c file: I prefer that to the <xen/*_int.h> approach as it
keeps private non-shared stuff all in one place.

 -- Keir



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> > Note that this is compile-tested but not run tested yet.  I
> > thought I''d get feedback on the approach before I get much
> > further.
> 
> The approach is fine as far as I''m concerned. It should just 
> replace the
> existing xmalloc.c of course: no point in keeping the old one around.
> Therefore may as well put the whole implementation in 
> xmalloc.c, or call it
> xmalloc_tlsf.c if you''re really keen to keep the name of the 
> algorithm in
> the file name (in which case xmalloc.c should be entirely deleted; or
> perhaps temporarily make it a build option which .c file gets built if
> really worried that the new xmalloc implementation may have 
> subtle bugs and
> we''d like to be able to revert for testing).
> 
> Structure definitions and the like which are private to TLSF 
> should live at
> the top of the .c file: I prefer that to the <xen/*_int.h> 
> approach as it
> keeps private non-shared stuff all in one place.
Sounds good.

You may note that the tlsf files borrowed from Nitin Gupta use Linux-style
indentation/formatting.  One of my reasons for not merging the tlsf
allocation with xmalloc is I was too lazy to reformat ;-)  Do I need
to do that or can I leave it as is or do you have a tool that will
auto-reformat it to meet the Xen style requirements?

Thanks,
Dan

P.S. Posted patch boots fine.

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On 15/10/08 20:59, "Dan Magenheimer"
<dan.magenheimer@oracle.com> wrote:
>> Structure definitions and the like which are private to TLSF
>> should live at
>> the top of the .c file: I prefer that to the <xen/*_int.h>
>> approach as it
>> keeps private non-shared stuff all in one place.
> 
> Sounds good.
> 
> You may note that the tlsf files borrowed from Nitin Gupta use Linux-style
> indentation/formatting.  One of my reasons for not merging the tlsf
> allocation with xmalloc is I was too lazy to reformat ;-)  Do I need
> to do that or can I leave it as is or do you have a tool that will
> auto-reformat it to meet the Xen style requirements?
If the patch is actually working fine then I can take it and do the
necessary reformatting. It only takes a short while even to do it manually.

You need to provide a signed-off-by line, by the way.

 -- Keir



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