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

From: Ric Wheeler
Date: Wed Jan 22 2014 - 09:11:54 EST


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

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