Re: 2.6.24-rc7: memory leak?

[CaT <cat@zip.com.au>]

On Thu, Jan 17, 2008 at 12:22:03PM +0100, Peter Zijlstra wrote:
> On Thu, 2008-01-17 at 17:34 +1100, CaT wrote:
> > cache). During the rsync the memory used grew to just shy of 1.6gig and
> > now, about 2 hours after the rsync has well and truly finished, the used
> > memory is at 1.23gig. This is what free reports:
> > 
> >              total       used       free     shared    buffers cached
> > Mem:       2058128    1994468      63660          0     688604 11432
> > -/+ buffers/cache:    1294432     763696
> > Swap:      1048568          0    1048568
> 
> How much memory does:
> 
>   echo 3 > /proc/sys/vm/drop_caches
> 
> gain you?

56M used now. Should all this cache usage not be counted towards the
'Cached' entry in meminfo rather then getting counted as part of used
ram. I assume that this would not cause an oom situation and would be
freed up if all that memory really did need to be used.

> > ext3_inode_cache  1235577 1240565    768    5    1 : tunables   54   27    8 : slabdata 248113 248113      0
> > dentry            703661 749797    200   19    1 : tunables  120   60    8 : slabdata  39463  39463      0
> > buffer_head       174535 209087    104   37    1 : tunables  120   60    8 : slabdata   5651   5651      0
> 
> would get freed by doing that.

They were indeed.

> this one:
> 
> > size-64           537590 850249     64   59    1 : tunables  120   60    8 : slabdata  14411  14411      0
> 
> I'm unsure about, if that one sticks around that'd be something to worry
> about. See if you can monitor this value and try to determine:

This went away also.

>  - if it ever drops
>  - what makes it grow (fastest)
> 
> I guess we could stick some instrumentation in there to track that
> bucket.

Might help prevent upraised eyebrows or worse. :)

-- 
    "To the extent that we overreact, we proffer the terrorists the
    greatest tribute."
    	- High Court Judge Michael Kirby