Re: DMA memory shortage?
H. Peter Anvin (hpa@transmeta.com)
10 Dec 1998 23:06:08 GMT
Followup to: <Pine.LNX.3.96.981209145740.2691A-100000@biznatch.nick.org>
By author: "Nicholas M. Kirsch" <nkirsch@biznatch.nick.org>
In newsgroup: linux.dev.kernel
>
> I'm running kernel version 2.1.130 on a Dual PPro. Everything has worked
> beautifully until today, when I got this while trying to format a floppy :
>
> yoda:/tmp# mkfs.msdos /dev/fd0
> mkfs.msdos 0.4, 27th February 1997 for MS-DOS/FAT/FAT32 FS
> DMA memory shortage. Temporarily falling back on virtual DMA
> mkfs.msdos: unable to open /dev/fd0
>
> I have 320 MB of memory, so this is very odd.
>
> total used free shared buffers cached
> Mem: 322052 321000 1052 16392 172216 116576
> -/+ buffers/cache: 32208 289844
> Swap: 0 0 0
>
> I have no I/O processes running, just two highly CPU intensive tasks, but
> they have priority 20.
>
This is very common if you have large amounts of memory, since only
the first 16 MB is usable for ISA DMA. I think if you have enough
memory I think it is the right thing to save a pool of DMA-capable
pages for that purpose only; I have been meaning to implement such a
hack.
-hpa
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