lkml.org 
[lkml]   [1999]   [May]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [VFS] move active filesystem
Date
>On Thu, May 13, 1999 at 03:48:42PM -0600, WANG,YIDING (HP-SanJose,ex1)
wrote:
>> Linux has DMA memory allocation limitation to max. 128K - 24 bytes.
>> Does anyone know how to break the limitation in driver to allocate more
DMA
>> memory, say 256K?
>
>And what about a more inteligent DMA memory allocator ? I mean, in case
>of fragmented memory it's very frequent not to success to allocate DMA
>memory by kernel (eg by sound/floppy modules). Why does not kernel
>moves some memory, changing some pagetable entries etc to create
>contigous memory area suitable for DMA (in low 16M for ISA DMA, care of
>page boundaries etc). If there's enough memory to do it, it would be
>only some memory moving action to get the suitable place.
>
>(I don't know too much about Linux kernel internals, maybe DMA memory
>allocating is something atomic operation which blocks the kernel too long
>to do such an operation I described below ?)
>
>Thanx : Gabor,
>


Welsh's bigphysarea is less intellegent, not more, but you might look at:
http://web.mountain.net/~tleete/bigphysarea-config-2.2.9-patch.gz
which applies fairly clean to any 2.2.x or
http://web.mountain.net/~tleete/bigphysarea-config-2.3.3.gz

It works by grabbing memory before the vm subsystem starts, and using its
own private allocators. No swapping involved, relieves vm of a lot of
incipient thrashing.

Regards,
TML



-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:51    [W:0.023 / U:1.952 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site