Re: __flush_cache_all() miscellany

[Ralf Baechle <ralf@oss.sgi.com>]

On Wed, May 29, 2002 at 11:46:58PM +0200, Maciej W. Rozycki wrote:

> > >  I converted a few flush_cache_all() invocations to __flush_cache_all() 
> > > where appropriate late last year, but the function is a bit older.  I
> > > think you might dig the linux-kernel list archives for a discussion on the
> > > semantics of flush_cache_all() (it's a nop for many MIPS CPUs) and
> > > friends.  The short description in Documentation/cachetlb.txt is a bit
> > > insufficient, I'm afraid. 
> > 
> > I don't like that function very much; it's sort of a shotgun approach
> > to flushing caches in a part of the kernel that's not too performance
> > relevant.  The whole interface sucks, should be replaced by something
> > more finegrained.
> 
>  Well, I suspect the API might be somewhat influenced by SPARC's oddities. 
> ;-) 

Historically that's certainly true.

As a general complaint about the style of interfaces of the cache stuff -
they're too low level.  Frequently we just don't know enough about the
situation to optimize the flush operation.

  Ralf