On Saturday 11 December 2004 19:27, [EMAIL PROTECTED] wrote: > I'm continuing to find the 2.6.8.1 w/ ska3-v7 host and 2.6.9 w/ bb4 very > stable. However, now that I've gotten beyond, what I consider, > infrastructure problems, I'm seeing behavior I don't understand.
> I'm specifically investigating uml from the perspective of partitioning > hardware resources, in this case persistant and volatile memory, so my > guests are running their root file and swap filesystems on their own > dedicated disk partitions. [...] > At this point `top` on the host shows approx. 153040 used 101352 avail. > > `df /mnt/ram6` shows over 50000K available. > > Even though `top` on the guest shows approx. 56916 ttl 20032 used 36884 > avail > > > If I now run `find / -name "*.c" -print | xargs grep include` in the guest > the host's available memory gets sucked down to the 2500 - 2000 K range in > about three seconds. Which value are you using from "free" output? Make sure you're using the "-/+ buffers/cache:" one, which is the only one to use. > The guest's available memory eventually gets sucked down to about 850k but > it takes at least twice as long as on the host. > > Neither the host nor the guest use any swap. > > `df /mnt/ram6` (host of course) still shows over 22000K available. > > > If I `halt` the guest, the host jumps from 2500K to almost 150000K > available just as the guest "powers down". > > `df /mnt/ram6` is now back to over 60000K available. > > > > So it seems my guest is using some of my ram disk, but only about two > thirds of it -- and a lot of host ram. > > > > In an attempt to test this, I rebooted and repeated all the above steps, > except I lied to the uml and told it that it had three times more memory > than the $TMPDIR partition. > > `linux ubd0=/dev/hda6 ubd1=/dev/hda5 mem=180000K > eth0=tuntap,,,192.168.0.254` > > `top` on the guest now happily reported 153240K available at the start. > > Everything went down similarly when I ran the `find`; the host sucked down > its available memory very quickly -- although this time it did eventually > swap. The guest gobbled up its available memory also, but at a slower > rate. I expected it to crash after it used 60000K, and then 120000K, but it > used up just about all its reported "available" memory and still kept > running for a while. It never used any of its own swap. > Continuously running `df /mnt/ram6` showed the free memory eventually go > right to zero, shortly before the guest segfaulted. Checked the value without the cache size? > My impression is that the guest is not using its "dedicated" ram or swap > very efficiently. 2.6.9 kernels, on any arch, often go OOM instead of swapping (discussed somewhere on http://lwn.net/Kernel). > It also seems to be able to get into the host's ram > somehow. Hmm, quite unlikely... -- Paolo Giarrusso, aka Blaisorblade Linux registered user n. 292729 http://www.user-mode-linux.org/~blaisorblade ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://productguide.itmanagersjournal.com/ _______________________________________________ User-mode-linux-user mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
