[Pkg-uml-pkgs] Bug#388128: user-mode-linux: eats up the whole /dev/shm

Andreas Beckmann debian at abeckmann.de
Mon Sep 18 18:57:57 UTC 2006

Package: user-mode-linux
Version: 2.6.17-1um-2
Severity: normal


running several uml guests can consume the whole /dev/shm quickly: e.g.
host mem: 1GB
/dev/shm: 507 MB (default tmpfs size)
2x linux mem=256m: 512MB ==> greater than /dev/shm
One uml guest crashed, the other could be shut down, but this took
nearly forever.

Obviously the 'physical memory' used by the uml guests is taken from
/dev/shm and won't be freed again.
linux --help says "mem= ... is not releated to the amount of memory in
the host. ... can be more ... will be swapped out."
Even using half of the host memory seems to be impossible under this
Is there a way to reduce /dev/shm usage?

The host has enough swap (4GB) and tmpfs space available at /tmp (3GB).
More could be made available, if neccessary.

The host and guest kernels are plain debian kernels without any
additional patches.


-- System Information:
Debian Release: testing/unstable
  APT prefers testing
  APT policy: (500, 'testing'), (500, 'stable'), (300, 'unstable'), (30, 'experimental')
Architecture: i386 (i686)
Shell:  /bin/sh linked to /bin/bash
Kernel: Linux 2.6.17-2-k7
Locale: LANG=C, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)

Versions of packages user-mode-linux depends on:
ii  uml-utilities                 20060323-3 User-mode Linux (utility programs)

user-mode-linux recommends no packages.

-- no debconf information

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