[vdr] Is there a way to give inode entries a higher cache priority than data in the linux kernel?

Matthias Schniedermeyer ms at citd.de
Wed Feb 14 16:18:42 CET 2007


Carsten Koch wrote:
> I have a distributed VDR system in my house with a lot of disks
> that are NFS mounted by VDR PCs in two rooms.
> In order to conserve energy, I have used hdparm to set a spin down
> delay after which the disks turn themselves off.
> When /video/.update is touched (one of the VDR PCs creates/deletes/
> edits a recording, I move a recording into a folder, etc.) or when
> the vdr program is started, it reads all directories from all disks.
> Most of these directories are unchanged, so there really is no need
> to spin up the disk just to read a few inode entries.
> However, my observation is that they are always spun up.
> So my questions are:
> 
> 1) Is there a bug in the linux kernel that makes it spin up
>    the disk needlessly even if the data are still in the cache?
> 
> 2) Is there a way to configure the kernel, so the inode entries
>    are locked in the cache or at least get a much higher
>    cache priority than ordinary data?

I haven't tried or read it myself, but this:
Documentation/laptop-mode.txt
might contain the information you need.
At least your problems sounds like the typical laptop-problem to me.


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