Re: [Lsf-pc] [LSF/MM TOPIC] really large storage sectors - going beyond 4096 bytes

Ric Wheeler
2014-01-22T14:10:48Z

On 01/22/2014 04:34 AM, Mel Gorman wrote:
> On Tue, Jan 21, 2014 at 10:04:29PM -0500, Ric Wheeler wrote:
>> One topic that has been lurking forever at the edges is the current
>> 4k limitation for file system block sizes. Some devices in
>> production today and others coming soon have larger sectors and it
>> would be interesting to see if it is time to poke at this topic
>> again.
>>
> Large block support was proposed years ago by Christoph Lameter
> (http://lwn.net/Articles/232757/). I think I was just getting started
> in the community at the time so I do not recall any of the details. I do
> believe it motivated an alternative by Nick Piggin called fsblock though
> (http://lwn.net/Articles/321390/). At the very least it would be nice to
> know why neither were never merged for those of us that were not around
> at the time and who may not have the chance to dive through mailing list
> archives between now and March.
>
> FWIW, I would expect that a show-stopper for any proposal is requiring
> high-order allocations to succeed for the system to behave correctly.
>

I have a somewhat hazy memory of Andrew warning us that touching this code takes
us into dark and scary places.

ric