Re: fork: out of memory
Albert D. Cahalan (acahalan@cs.uml.edu)
Fri, 28 Nov 1997 01:39:51 -0500 (EST)
Mike Jagdis writes:
> On Thu, 27 Nov 1997, Rik van Riel wrote:
>
>> 128 k would be enough, the largest DMA buffer allocated by devices
>> is 64k in size (soundcard) and ftape uses 3 32k area's. the scsi
>> tape driver also uses quite some space, but also multiple 32k
>> regions. floppy driver needs a small piece of dma memory (xxk?)
>> and some network/scsi cards do.
>
> I remain unconvinced that solving the problem for a limited
> range of known hardware on an ISA bus is a good solution for
> an OS that runs on many different system architectures for
> which new hardware is being constantly developed by third parties.
Reserved DMA space is the best solution _because_ Linux runs
on multiple architectures. Other solutions seem to involve much
more hackery, perhaps reducing performance accross all platforms.
256 kB ought to be enough, to be used only for DMA allocations
larger than the page size. Large systems (over 64 MB) could have
a full megabyte reserved for all DMA allocations.
The really nice thing about this solution is that is is simple
enough to go into 2.0.33. More advanced solutions can only go
into the 2.1.xx series.