Benjamin LaHaise <[email protected]> writes:
> On Wed, Mar 15, 2006 at 02:29:32PM -0700, Eric W. Biederman wrote:
>> If the impact is very slight or unmeasurable this means the option
>> needs to fall under CONFIG_EMBEDDED, where you can change if
>> every last bit of RAM counts but otherwise you won't care.
>
> But we have a data type that is correct for this usage: dma_addr_t.
Actually now that I think back there are machines with < 4GiB of ram
with 64bit pci BAR values. It is more common to have 32bit values BAR
values and > 4GiB of ram.
So I don't see dma_addr_t in general being the right choice.
Although I do suspect that in most cases dma_addr_t <= the
size of what is in struct resource.
Nor do I think struct resource is nearly as important when being
efficient, as dma_addr_t. struct resource is only used during
driver setup which is a very rare event. A few extra instructions
there likely will get lost in the noise and most of the will probably
be removed because they are in an __init section anyway.
Eric
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