Re: [PATCH v4] relatime: Make relatime smarter

From: Matthew Wilcox
Date: Tue Dec 02 2008 - 11:47:03 EST


On Tue, Dec 02, 2008 at 12:10:25PM +0100, Karel Zak wrote:
> On Fri, Nov 28, 2008 at 06:40:55AM -0700, Matthew Wilcox wrote:
> > On Fri, Nov 28, 2008 at 11:18:09AM +0000, Jamie Lokier wrote:
> > > Matthew Garrett wrote:
> > > > The time between atime updates can be configured at boot
> > > > with the relatime_interval kernel argument, or at runtime through a sysctl.
> > >
> > > Shouldn't it be a per-mount value, with defaults coming from the sysctl?
> >
> > Perhaps a more sensible question would be "Why make it configurable at
>
> this is GNOME-mentality :-)

Yes, I frequently pal around with terrorists.

> > all?" What's wrong with hardcoding 24 hours? Or, to put it another
> > way, who wants to change it from 24 hours, and why?
>
> Why do you think that 24 hours is the right default value? Do you
> have any logical argument for this setting?

Once a day seems like a good value to me. It's a good human being
timescale and still cuts down the number of atime updates by a lot.

If somebody really cares, they could graph the relatime_update value
against number of writes performed in a given period and determine a
better cutoff. I can think of a hundred better ways to spend my time
though.

Good job of not answering the question, by the way. Why _not_ 24 hours?

--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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