Re: SLAB vs. pci_alloc_xxx in usb-uhci patch

From: David S. Miller (davem@redhat.com)
Date: Mon Mar 05 2001 - 23:53:21 EST


Russell King writes:
> A while ago, I looked at what was required to convert the OHCI driver
> to pci_alloc_consistent, and it turns out that the current interface is
> highly sub-optimal. It looks good on the face of it, but it _really_
> does need sub-page allocations to make sense for USB.
>
> At the time, I didn't feel like creating a custom sub-allocator just
> for USB, and since then I haven't had the inclination nor motivation
> to go back to trying to get my USB mouse or iPAQ communicating via USB.
> (I've not used this USB port for 3 years anyway).

Gerard Roudier wrote for the sym53c8xx driver the exact thing
UHCI/OHCI need for this.

I think people are pissing their pants over the pci_alloc_consistent
interface for no reason. It gives PAGE<<order sized/aligned chunks
back to the caller at the request of Linus so that drivers did not
have to guess "is this 16-byte aligned..." etc.

Later,
David S. Miller
davem@redhat.com
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This archive was generated by hypermail 2b29 : Wed Mar 07 2001 - 21:00:19 EST