Re: Implementing NVMHCI...

[Grant Grundler]

On Sat, Apr 11, 2009 at 12:52 PM, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
>
> On Sat, 11 Apr 2009, Alan Cox wrote:
>>
>> > Â Â Â The spec describes the sector size as
>> > Â Â Â "512, 1k, 2k, 4k, 8k, etc." Â It will be interesting to reach
>> > Â Â Â "etc" territory.
>>
>> Over 4K will be fun.
>
> And by "fun", you mean "irrelevant".
>
> If anybody does that, they'll simply not work. And it's not worth it even
> trying to handle it.

Why does it matter what the sector size is?
I'm failing to see what the fuss is about.

We've abstract the DMA mapping/SG list handling enough that the
block size should make no more difference than it does for the
MTU size of a network.

And the linux VM does handle bigger than 4k pages (several architectures
have implemented it) - even if x86 only supports 4k as base page size.

Block size just defines the granularity of the device's address space in
the same way the VM base page size defines the Virtual address space.

> That said, I'm pretty certain Windows has the same 4k issue, so we can
> hope nobody will ever do that kind of idiotically broken hardware. Of
> course, hardware people often do incredibly stupid things, so no
> guarantees.

That's just flame-bait.ÂNot touching that.

thanks,
grant

>
> Â Â Â Â Â Â Â ÂLinus
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