Re: Warning - running *really* short on DMA buffers while doing file transfers

Pedro M. Rodrigues
2002-09-26T06:59:43Z

Jens Axboe wrote:
> On Wed, Sep 25 2002, Mathieu Chouquet-Stringer wrote:
>
>> Hello!
>>
>>I've upgraded a while to 2.4.19 and my box has been happy for the last 52
>>days (it's a dual PIII). Tonight while going through my logs, I've found
>>these:
>>
>>Sep 25 22:18:41 bigip kernel: Warning - running *really* short on DMA buffers
>>Sep 25 22:18:47 bigip last message repeated 55 times
>>Sep 25 22:19:41 bigip last message repeated 71 times
>
>
> This is fixed in 2.4.20-pre
>
>

I reported this same problem some weeks ago -
http://marc.theaimsgroup.com/?l=linux-kernel&m=103069116227685&w=2 .
2.4.20pre kernels solved the error messages flooding the console, and
improved things a bit, but system load still got very high and disk read
and write performance was lousy. Adding more memory and using a
completely different machine didn't help. What did? Changing the Adaptec
scsi driver to aic7xxx_old . The performance was up 50% for writes and
90% for reads, and the system load was acceptable. And i didn't even had
to change the RedHat kernel (2.4.18-10) for a custom one. The storage
was two external Arena raid boxes, btw.

Regards,
Pedro