[RFC PATCH v6] Documentation/arch: Add Documentation/arch-features.txt

[Ingo Molnar]

* Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Wed, May 13, 2015 at 11:47:56AM +0200, Ingo Molnar wrote:
> >  - introduce the '..' denotion (in the final table) to show features 
> >    that cannot be supported by an architecture due to hardware 
> >    dependencies:
> > 
> > 		   gcov-profile-all:---------------.
> > 				THP:--------.      |
> > 		      irq-time-acct:-.      |      |
> > 				     |      |      |
> > 		----------------------------------------
> > 		  alpha           | TODO | TODO | TODO |
> > 		  arc             | TODO |  ..  | TODO |
> > 		  arm             |  ok  |  ok  |  ok  |
> > 		  arm64           | TODO |  ok  |  ok  |
> > 		  avr32           | TODO |  ..  | TODO |
> > 		  blackfin        | TODO |  ..  | TODO |
> > 		  c6x             | TODO |  ..  | TODO |
> > 
> >    so in the 'THP' column, if an architecture could in theory support 
> >    THP, it's listed as 'TODO', if it cannot, it's listed as '..'.
> 
> Shouldn't exactly that explanation be in the text file itself too?

Yeah, indeed, added it.

> Also, how about s/TODO//g for less clutter:

No, I'd like there to be a very visible 'TODO' item for missing 
features.

The 'clutter' shows how badly our generic kernel features are 
propagating :-/ We hope to reduce this clutter in the future.

Updated patch attached - I've added a few more features to the last 
table, and restructured the explanations, now every feature 
description also lists the Kconfig variable that it's tracking, e.g.:

      irq time acct: HAVE_IRQ_TIME_ACCOUNTING
                THP: HAVE_ARCH_TRANSPARENT_HUGEPAGE && 64BIT
   gcov profile all: ARCH_HAS_GCOV_PROFILE_ALL
    rwsem optimized: Optimized asm/rwsem.h
   queued spinlocks: ARCH_USE_QUEUED_SPINLOCKS
     queued rwlocks: ARCH_USE_QUEUED_RWLOCKS
     numa balancing: ARCH_SUPPORTS_NUMA_BALANCING && 64BIT && NUMA

Thanks,

	Ingo

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