Re: [patch?] Re: Do ramdisk exec's map direct to buffer cache?

From: Alan Cox (
Date: Tue Aug 01 2000 - 17:57:01 EST

> Strive for a good, stable system that avoids _most_ of the bad performance
> under normal load. And be prepared to live with the fact that there will
> always be things you can do to make it behave in nasty ways.
> Right now I want things to _work_. Big VM changes are for 2.5.x anyway.
> (See 2.2.x for how playing with the VM can cause untold stability woes. I
> think Alan learned that the hard way).

Yes. Its taken from 2.1.121 or so to 2.2.17pre to get the VM acceptable, and
it'll take another 2 or 3 releases doing only gradual tested changes to verify
the final few bits to get it to be almost as good as 2.0.

For just about every load I've tested 2.0 is the best stable VM we ever had,
late 2.1 was better, 2.2 was bad, 2.4 I can get to the point the box stalls
for 45 seconds - as any user.

Most of the post 2.4 proposals look good, because we know they work well and
the overhead looks like it can be no worse than in 2.4 for the light load
cases. FreeBSD is a very nice test suite for that.

No argument - we cannot do major VM work for 2.4, it'll just have to
be tuned to try and get it as good as 2.2. Post 2.4 I'll take a look at doing
a 2.4.x-ac with the newer VM work and whatever else escapes for later folding
in, providing 2.2 is rock solid by then.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
Please read the FAQ at

This archive was generated by hypermail 2b29 : Mon Aug 07 2000 - 21:00:07 EST