|From:||"Thomas E. Spanjaard" <tgen@xxxxxxxxxxxxx>|
|Date:||Tue, 23 Jan 2007 18:44:35 +0000|
When I start a qemu virtual machine with, say, 128 MB of RAM, then that memory is allocated to the qemu process in a normal way, i.e. it can also be paged to swap.
If I understand you correctly, then DF's virtual kernels work differently: they delegate the allocations to the real kernel. Right? I guess that means that the memory of user processes running in the vkernel can be paged to swap, while the pages of the vkernel (its virtual KVM, so to speak) are locked to physical RAM, just like the real kernel. Is that correct?
What about the cache (VM cache, buffer cache, whatever). During normal operation, a kernel tends to use almost all free RAM for the cache, i.e. there is almost zero free RAM. Do the virtual kernels behave the same? Do they even have their own caches?
I guess what I'm really trying to ask is this: If I start 4 vkernels, each with 256 MB RAM, will they use 1 GB of real memory, even if only a few small processes run inside them?
Cheers, -- Thomas E. Spanjaard firstname.lastname@example.org
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