On 12/06/2009 07:47 PM, malc wrote:
It will never fail on Linux. On other hosts it prevents a broken oom handler
from taking the guest down a death spiral.
It fails here all the time i'm sorry to say, i have overcommit disabled
(mostly because kpdf when doing a text search tends to overwhelm the VM
subsystem and Linux happily picks X11 as it's OOM kill target)
Right, I meant under the default configuration. Unfortunately there is
no good configuration for Linux - without strict overcommit you'll
invoke the oom killer, with strict overcommit you'll need ridiculous
amounts of swap because fork() and MAP_PRIVATE require tons of backing
store.
On my home machine I have
$ grep Commit /proc/meminfo
CommitLimit: 7235160 kB
Committed_AS: 4386172 kB
So, 4GB of virtual memory needed just to run a normal desktop with
thunderbird+firefox. Actual anonymous memory is less than 2GB, so you
could easily run this workload on a 2GB machine without swap, but with
strict overcommit 2GB RAM + 2GB swap will see failures even though you
have free RAM.
--
Do not meddle in the internals of kernels, for they are subtle and quick to
panic.
