Re: Linux 2.6.29

From: Linus Torvalds
Date: Thu Mar 26 2009 - 23:41:23 EST




On Thu, 26 Mar 2009, Andrew Morton wrote:
>
> Why does everyone just sit around waiting for the kernel to put a new
> value into two magic numbers which userspace scripts could have set?
>
> My /etc/rc.local has been tweaking dirty_ratio, dirty_background_ratio
> and swappiness for many years. I guess I'm just incredibly advanced.

.. and as a result you're also testing something that nobody else is.

Look at the complaints from people about fsync behavior that Ted says he
cannot see. Let me guess: it's because Ted probably has tweaked his
environment, because he is advanced. As a result, other people see
problems, he does not.

That's not "advanced". That's totally f*cking broken.

Having different distributions tweak all those tweakables is just even
_more_ so. It's the anti-thesis of "advanced". It's just stupid.

We should aim to get it right. The "user space can tweak any numbers they
want" is ALWAYS THE WRONG ANSWER. It's a cop-out, but more importantly,
it's a cop-out that doesn't even work, and that just results in everybody
having different setups. Then nobody is happy.

Linus

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