On Fri, Nov 25, 2016 at 03:39:17PM +0000, Daniel P. Berrange wrote:
On Fri, Nov 25, 2016 at 04:35:14PM +0100, Martin Kletzander wrote:
On Fri, Nov 25, 2016 at 03:19:54PM +0100, Viktor Mihajlovski wrote:
On 18.11.2016 17:44, Viktor Mihajlovski wrote:
With kernel 3.18 (since commit 3e32cb2e0a12b6915056ff04601cf1bb9b44f967) the "unlimited" value for cgroup memory limits has changed once again as its byte value is now computed from a page counter. The new "unlimited" value reported by the cgroup fs is therefore 2**51-1 pages which is (VIR_DOMAIN_MEMORY_PARAM_UNLIMITED - 3072). This results e.g. in virsh memtune displaying 9007199254740988 instead of unlimited for the limits.
Ah, I wonder hoe many times we'll have to deal with this.
Anyway, this means it is not enough to shift by 2 if the system hugepage is more than 4k (e.g. 2M). I remember we had to change something due to such hosts. virGetSystemPageSize(KB) should help with that.
We could also make it 2^50 - pagesize just to make sure it will work for a while, but some might not like it.
I guess I'm not understanding how this code copes with the fact that we now have 3 different "unlimited" values to deal with.
Could we not simply record the unlimited values and pick the right one based on kernel version we detect ?
We have one, which we return for Get APIs that means that the setting was not restricted. We would need to have a cgroup which we set to some huge value and then read it, store it and compare it all the time. It _should_ work as far as I can tell.
Regards, Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://entangle-photo.org -o- http://search.cpan.org/~danberr/ :|