> Now, even in the case of DMA ram, IFF the OS has a clean way for
> the app to get the RAM and then tell the driver to use it, such
> that it cannot be freed out from underneath the driver's feet,
> then we should do it that way to honor ulimits, but if not, we
> must have the chipset driver alloc it, for security reasons.
AFAIK mmaping stuff should amount to the ulimits. If not, it isn' soo
bad, because the driver can limit the total amount easily and it should
do so anyway, as DMA-able RAM might be a rare ressource, so that a few
hundred user programs allocing a few MB of it, which would be perfectly
within their ulimits, would eventually result in a DoS to the SCSI
subsystem or similar. IMHO such pages should be mmaped from a driver
that will internally limit its usage.
Moreover when console-switching, the DMA must be halted anyway, so it
might be possible to use a shared mapping.
CU, Andy
--
Andreas Beck | Email : <[EMAIL PROTECTED]>
