[linux-dvb] Re: kernel memleak with DVB drivers

Stefan Seyfried seife at gmane0305.slipkontur.de
Sat Jun 18 23:50:39 CEST 2005


On Sat, Jun 18, 2005 at 08:07:17PM +0200, Johannes Stezenbach wrote:
 
> VDR does EPG scanning all the time, if there's be a leak I guess

maybe most people use VDR with FF cards?

> someone had noticed already.
> 
> How do you measure the "10MB kernel memory lost"?

start the machine with almost no services running
log the output of "free", /proc/slabinfo and /proc/meminfo

start the epg scanner, basically:
--------------------------------------------------
#!/bin/bash
for i in arte ZDF N24 BR-alpha Eurosport VOX; do
	tzap -r $i > /dev/null 2>&1 &
	pid=$!
	tv_grab_dvb > /dev/null
	kill $pid
	sleep 1
done

after this, log "free", /proc/slabinfo and /proc/meminfo again.
Repeat.

free shows about 10mb "used" more after every round. Everything
else looks normal. After ~25 to 30 rounds, the machine runs OOM,
without even starting to swap (sure, kernel memory cannot be swapped).

I also checked with the suse kernel gurus at work - they also wanted
to talk me out of the "kernel memleak" theory but did not succeed ;-)
-- 
Stefan Seyfried





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