Re: blib kernel dependency patch

[Savin Zlobec <savin at elatec dot si>]

Andrew Lunn wrote:

> On Mon, Jun 28, 2004 at 11:14:14AM +0200, Savin Zlobec wrote:
>  
>
> > Hi,
> >
> > this patch changes the cyg_mempool_fix_* based internal blib block 
> > memory pool managment
> > with custom (much simpler) block memory pool funs. With this change blib 
> > no more depends on
> > the kernel package.
> >
> > savin
> >    
>
> I don't think the memalloc package is dependent on the kernel. There
> is something in the docs/notes.txt about this. Do we realy need yet
> another set of memory allocation functions?
>
> Having said that, i've never tried to use the package without the
> kernel. So i've no idea how easy it is to make it work.
>  
The cyg_mempool_fix/var* API funs are defined in the file kapi.cxx which
compilation is conditioned in memalloc.cdl with 'active_if  CYGPKG_KERNEL'.
The file consists only of C wrappers for Cyg_Mempool_Variable and
Cyg_Mempool_Fixed C++ objects (which don't depend on the kernel), but
this are the only C wrappers for this two objects.

Regrardless of that the new implementation of block memory pool is
smaller/faster than using cyg_mempool_fix API. Each block header
already contained the 'struct list_head' linked list pointers which are
now used also for linking free blocks in a free block list. The new
implementation doesn't require more RAM, the block allocation and
freeing is more simple/faster (a matter of taking the first block
from the linked list or putting it back), the code size increment is just
a couple of lines and it doesn't require the memalloc package any more.

I'am in the process of reworking the fatfs to get rid of malloc and any
kernel dependencies - I have already a working version without the FAT
table entries cache which didn't provide any performance gain with most
file ops and slowed/complicated access with bigger files. Now the fileio1
test flyes and it all should compile in nonkernel configurations.

savin