Re: Memory Measurements and Lots of Files and Inodes

[Andrew Morton <akpm@digeo.com>]

"Patrick R. McManus" wrote:
> 
> ...
> > If you could share your test apps that would help a lot.
> 
> sure! this is the "lots of files" program.

Yep, negative dentries:

      dentry_cache:   149092KB   149092KB  100.0 
  ext3_inode_cache:     3425KB    10102KB   33.90
   radix_tree_node:      594KB     1612KB   36.88
       buffer_head:      543KB     1264KB   42.99


You can monitor these via /proc/slabinfo, or using Bill's bloatmeter
script from http://www.zip.com.au/~akpm/linux/patches/stuff/

> ...
> 
> > On your machine it'll be "all of swap plus all of physical memory
> > minus whatever malloc'ed memory you're using now minus 8-12 megabytes".
> > There isn't much memory which cannot be reclaimed unless you have a
> > huge machine or you're doing odd things.
> 
> this is useful advice, thanks. Basically what the new procps does?

I don't know what procps does.

But your fill-up-all-memory program will certainly do the trick.
Run it, create a huge swapstorm (or get oom-killed if there's no
swap) and then see what `free' says.  That's as much memory as the
kernel will ever give you.