Re: [PATCH] 2.4 laptop mode

From: Tim Connors (
Date: Mon Jun 09 2003 - 02:44:00 EST

In linux.kernel, you wrote:
> Now, this isn't the prettiest patch in the world. But it does allow me
> to get good spin down times on my laptop hard drive. It was somewhat
> inspired by the 2.5.early version akpm did. Basically, it adds:

OK - this is a much nicer thing than noflushd (which, for a lot of
people, manages to cause anything using pthreads to not reap zombies
anymore). There is still one deficiency (well, two) though:

One is that it assumes you only have one drive (I was to use this on
my desktop as well, which doesn't have me infront of it for 16 hours a
day). So when one drive spins up and the writes are performed, the
other drive needs to spin up at the same time (one of my drives is
basically /boot and /dos, so never gets accessed once booted). Is
there a way of doing the write deffering on a per-partition basis,
instead of all at once?

Second, given that at least one of my drives (even on my laptop, which
stays powered up 24/7) is not accessed for 16 hours at a time, I
increase the bdflush max params to 86400*HZ - is this safe? Is there a
reason why this is limited to 10000*HZ by default? Yeah, I know - I do
a manual sync when I need something to be safely stored on disk.

Thanks for the good work.

TimC --

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