Memory usage for ubifs writes

Lluís Batlle i Rossell viriketo at
Sun Jun 19 15:48:35 EDT 2011

On Sun, Jun 19, 2011 at 07:51:53PM +0200, David Kuehling wrote:
> >>>>> "David" == David Kuehling <dvdkhlng at> writes:
> > Hi,
> > when trying to save a 17kB file in Emacs to my 1.5GB ubifs data
> > partition, the OOM killer kills emacs, although at least 5MB of RAM
> > should still be available.  This could be an emacs problem, but I
> > somehow doubt it.
> > Is ubifs somehow very memory hungry (does it need much memory to move
> > eraseblocks around?)
> Do we have a general memory usage problem?  (Note: i'm running a
> openwrt-_trunk_ nightly build from a few weeks ago)
> Typing 'free' it says:
>              total       used       free     shared    buffers     cached
> Mem:         28048      15392      12656          0          0       1220
> -/+ buffers/cache:      14172      13876
> Swap:            0          0          0
> 14 MB RAM in usage by default?  IIRC that's more than a minimal Debian
> system uses!

I wrote this tool to get nicer memory reports. It takes a while to understand
the numbers...
depending on the kernel version, you may need to adjust the code though.

Feel free to try it. It needs swap to build *in* the nanonote, but you should be
able to cross-build it easily. It needs some special kernel parameters enabled;
I don't know if your kernel will have them.


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