Re: The reason to call it 3.0 is the desktop (was Re: [OT] 2.6 not 3.0 - (NUMA))

Linus Torvalds
2002-10-07T18:47:20Z

On Mon, 7 Oct 2002, Andrew Morton wrote:
>
> Devices do physical readahead, and it works nicely.

Indeed. There isn't any reasonable device where this isn't the case: the
_device_ (and sometimes the driver - floppy.c) does a lot better at
readahead than higher layers can do anyway.

> Go into ext2_new_inode, replace the call to find_group_dir with
> find_group_other.

I hate that thing. Hate hate hate. Maybe we should just do this, and hope
that somebody will do a proper off-line cleanup tool.

In the meantime, it might just be possible to take a look at the uid, and
if the uid matches use find_group_other, but for non-matching uids use
find_group_dir. That gives a "compact for same users, distribute for
different users" heuristic, which might be acceptable for normal use (and
the theoretical cleanup tool could fix it up).

Add some other heuristics ("if the difference between free group sizes is
bigger than a factor of two"), and maybe it would be useful.

The current approach sucks for everybody, and makes it impossible to get
good throughput on a disk on many very common loads.

Linus