On Thu, 2011-01-20 at 05:33 +0800, David Nicol wrote:

On Wed, Jan 19, 2011 at 2:34 PM, Andrew Morton
[off-list ref] wrote:

quoted

It would be much more valuable if those 3.5 seconds were available to
devices which really really care about bootup times, but very few of
those devices use rotating disks nowadays, I expect?

And don't rotating disk modules read and buffer whole tracks, doing
their own readahead, anymore, anyway? Isn't that part of what "on-disk
cache" does?

The disk readahead and the metadata readahead is completely different,
you didn't even look at the patch or log before saying this.