How can I enable cgroups2 on my laptop? On Fri, Oct 19, 2018, 17:27 Lennart Poettering <mzerq...@0pointer.de> wrote:
> On Fr, 19.10.18 09:12, Florian Weimer (fwei...@redhat.com) wrote: > > > >> (cross-posting to devel and desktop lists, ideally reply to both) > > > > > > Coincidentally, at All Systems Go! in Berlin last week I had some > > > discussions with kernel people about RLIMIT_NOFILE defaults. They > > > basically suggested that the memory and performance cost of large > > > numbers of fds on current kernels is cheap, and that we should bump > > > the hard limit in systemd for all userspace processes. > > > > Which kernel version is that? Is that a new patch? Or some older > > kernel? > > > > It's definitely not true for kernel 4.18, see the script I posted. > > I inquired Tejun Heo about this all, this is what he replied: > > <snip> > In cgroup1, socket buffers are handled by a separate memory > sub-controller. It's cumbersome to use, somewhat broken and doesn't > allow for comprehensive memory control. cgroup2, however, by default > accounts socket buffer as part of a given cgroup's memory consumption > correctly interacting with socket window management. > > OOM killer too fails to take socket buffer into account and high > number of sockets can lead it to make ineffective decisions; however, > this failure mode isn't confined to high number of sockets at all - > fewer number of fat pipes, tmpfs, mount points or any other kernel > objects which can be pinned by processes can trigger this. > > cgroup2 can track or control most of these usages and at least for us > switching to oomd for workload health management solves most of the > problems that we've encountered. In the longer term, the kernel OOM > killer can be improved to make better decisions too. > </snip> > > ("us" in the above is facebook btw.) > > So, yeah, if we'd use cgroupv2 on Fedora, then everything would be > great (unfortunately the container messiness blocks that for now). But > as long as we don't, lifting the fd limit is not really making things > worse, given that there are tons of other easily exploitable ways to > acquire untracked memory... > > Lennart > > -- > Lennart Poettering, Red Hat > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > To unsubscribe send an email to devel-le...@lists.fedoraproject.org > Fedora Code of Conduct: https://getfedora.org/code-of-conduct.html > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: > https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org >
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