[FYI/PATCH 3/3] increase direct mapping sizes for spufs

[Arnd Bergmann]

On Tuesday 14 February 2006 02:58, Utz Bacher wrote:
> This patch applies on top of Arnd's postings (patch ids 4192, 4185, 4190)
> from 1/17 (on top of 2.6.15.4).
> It maps 16k instead of 4k for each problem-state mapped subarea. The mfc
> mapping contains the Multisource Synchronization Area, the MFC Command
> Parameter Area and the MFC Command Queue Control Area; the cntl mapping
> contains the SPU Control Area while the signal1 and signal2 mapping
> contain the relevant Signal-Notification Area.
> This allows libspe to build on direct problem state mapping and is
> recommended for running on a Cell blade today. The code may change in the
> near future.
> 
> Cc: Mark Nutter <mnutter at us.ibm.com>
> Cc: Arnd Bergmann <arndb at de.ibm.com>
> From: Ulrich Weigand <Ulrich.Weigand at de.ibm.com>
> Signed-off-by: Utz Bacher <utz.bacher at de.ibm.com>

Nack.

Both the intent and the implementation are flawed. Please keep the
size of each problem state mapping to one page. Your description
is not completely clear on the actual problem. I assume that the code
that I posted earlier had the wrong start address for the MFC page,
if that's what happened, please just fix the start address.

Last time we discussed this, the understanding was that the Multisource
Synchronization Area does not need to be exposed to user space. If a 
need for that has now come up, we should add a new file for it that
also allows synchronizing with file operations. Alternatively, we
could implement that as a 'fsync' file operation on the mfc file.

	Arnd <><