Finally got a chance to implement this, so testing this on my centos7 hosts, and it looks good. I’ll keep eye on it for a couple days, but after a couple of hours, there’s no evidence of any leakage.
On Mar 30, 2015, at 4:14 PM, John Taylor <jtt77777@yahoo.com> wrote:
Dan Kenigsberg <danken@redhat.com> writes:
On Sat, Mar 28, 2015 at 10:20:25AM -0400, John Taylor wrote:
Daniel Helgenberger <daniel.helgenberger@m-box.de> writes:
Hello Everyone,
I did create the original BZ on this. In the mean time, lab system I used is dismantled and the production system is yet to deploy.
As I wrote in BZ1147148 [1], I experienced two different issues. One, one big mem leak of about 15MiB/h and a smaller one, ~300KiB. These seem unrelated.
The larger leak was indeed related to SSL in some way; not necessarily M2Crypto. However, after disabling SSL this was gone leaving the smaller leak.
I think there are, at least for the purpose of this discussion, 3 leaks: 1. the M2Crypto leak 2. a slower leak 3. a large leak that's not M2Crypto related that's part of sampling
My efforts have been around finding the source of my larger leak, which I think is #3. I had disabled ssl so I knew that M2Crypto isn't/shouldn't be the problem as in bz1147148, and ssl is beside the point as it happens with a deactived host. It's part of sampling which always runs.
What I've found is, after trying to get the smallest reproducer, that it's not the netlink.iter_links that I commented on in [1] that is the problem. But in the _get_intefaces_and_samples loop is the call to create an InterfaceSample and that has getLinkSpeed() which, for vlans, ends up calling ipwrapper.getLink, and that to netlink.get_link(name)
netlink.get_link(name) *is* the source of my big leak. This is vdsm 4.16.10, so it is [2] and it's been changed in master for the removal of support for libnl v1 so it might not be a problem anymore.
def get_link(name): """Returns the information dictionary of the name specified link.""" with _pool.socket() as sock: with _nl_link_cache(sock) as cache: link = _rtnl_link_get_by_name(cache, name) if not link: raise IOError(errno.ENODEV, '%s is not present in the system' % name) return _link_info(cache, link)
The libnl documentation note at [3] says that for the rtnl_link_get_by_name function "Attention The reference counter of the returned link object will be incremented. Use rtnl_link_put() to release the reference."
So I took that hint, and made a change that does the rtnl_link_put() in get_link(name) and it looks like it works for me.
diff oldnetlink.py netlink.py 67d66 < return _link_info(cache, link) 68a68,70
li = _link_info(cache, link) _rtnl_link_put(link) return li
333a336,337
_rtnl_link_put = _none_proto(('rtnl_link_put', LIBNL_ROUTE))
Hope that helps. And if someone else could confirm that would be great.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1158108 [2] https://gerrit.ovirt.org/gitweb?p=vdsm.git;a=blob;f=lib/vdsm/netlink.py;h=af... [3] http://www.infradead.org/~tgr/libnl/doc/api/group__link.html#ga1d583e4f0b43c...
Thanks, John, for a great detective work.
I'm afraid that with even on the master branch we keep calling rtnl_link_get_link() and rtnl_link_get_by_name() without clearing the reference count, so a fix is due there, too.
Would you consider posting a fully-fledged fix to gerrit? I still need to understand what is the use of that refcount, so that we do not release it too early.
Regards, Dan.
Dan,
I'm happy to [1], although I've probably gotten something wrong with how it's supposed to be done :) It's for the version I'm using so it's for branch ovirt-3.5.
[1] https://gerrit.ovirt.org/#/c/39372/
Thanks, -John _______________________________________________ Users mailing list Users@ovirt.org http://lists.ovirt.org/mailman/listinfo/users