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Updated: 36 min 14 sec ago
The overlayfs filesystem
is being used more
and more these days, especially
in conjunction with containers. Amir Goldstein and Miklos Szeredi
led a discussion about recent and upcoming features for the filesystem at
Memory-management (MM) patches are notoriously difficult to get merged into the
mainline kernel. They are subjected to a high degree of review because
this is an area where it is easy to get things wrong. Or, at least, that
is how it used to be. The final memory-management session at the 2017
Linux Storage, Filesystem, and Memory-Management Summit was concerned with
patch review in the MM subsystem — or the lack of it.
Security updates have been issued by CentOS (icoutils and openjpeg), Debian (eject, graphicsmagick, libytnef, and tnef), Fedora (drupal8, firefox, kernel, ntp, qbittorrent, texlive, and webkitgtk4), Oracle (bash, coreutils, glibc, gnutls, kernel, libguestfs, ocaml, openssh, qemu-kvm, quagga, samba, samba4, tigervnc, and wireshark), Red Hat (curl), Slackware (mariadb), SUSE (samba), and Ubuntu (apparmor).
David Malcolm has put together the
beginnings of an unofficial guide to GCC
for developers who are getting
started with the compiler. "I’m a relative newcomer to GCC, so I
thought it was worth documenting some of the hurdles I ran into when I
started working on GCC, to try to make it easier for others to start
hacking on GCC. Hence this guide."
allows user space to intervene in the handling of page faults. As Andrea
Arcangeli and Mike Rapaport described in a 2017 Linux Storage, Filesystem,
and Memory-Management Summit session dedicated to the subject,
userfaultfd() was originally created to help with the live
migration of virtual machines between physical hosts. It allows pages to
be copied to the new host on demand, after the machine itself has been
moved, leading to faster, more predictable migrations. Work on
userfaultfd() is not finished, though; there are a number of other
features that developers would like to add.
A processor's translation lookaside buffer (TLB) caches the mappings from
virtual to physical addresses. Looking up virtual addresses is expensive,
so good performance often depends on making the best use of the TLB. In
the memory-management track of the 2017 Linux Storage, Filesystem, and
Memory-Management Summit, Mike Kravetz described a SPARC processor feature
that can improve TLB performance and explored ways in which that feature
could be supported.
of the Kubernetes orchestration system is available. "In
this release the community’s focus is on scale and automation, to help you
deploy multiple workloads to multiple users on a cluster. We are announcing
that 5,000 node clusters are supported. We moved dynamic storage
provisioning to stable. Role-based access control (RBAC), kubefed, kubeadm,
and several scheduling features are moving to beta. We have also added
intelligent defaults throughout to enable greater automation out of the
Google has announced
the launch of opensource.google.com
. "Today, we’re launching opensource.google.com, a new website for Google Open Source that ties together all of our initiatives with information on how we use, release, and support open source.
This new site showcases the breadth and depth of our love for open source. It will contain the expected things: our programs, organizations we support, and a comprehensive list of open source projects we've released. But it also contains something unexpected: a look under the hood at how we "do" open source."
When the transparent huge page feature was added to the kernel, it only
supported anonymous (non-file-backed) memory. In 2016, support for huge pages in the page cache
added, but only the tmpfs filesystem was supported. There is interest in
expanding support to other filesystems, since, for some workloads, the
performance improvement can be significant. Kirill Shutemov led the only
session that combined just the filesystem and memory-management tracks at
the 2017 Linux Storage, Filesystem, and Memory-Management Summit in a
discussion of adding huge-page support to the ext4 filesystem.
Security updates have been issued by Debian (eject, gst-plugins-bad1.0, gst-plugins-base1.0, gst-plugins-good1.0, gst-plugins-ugly1.0, gstreamer1.0, php5, and tiff), Fedora (kernel), Gentoo (curl, deluge, libtasn1, and xen-tools), Mageia (mbedtls, putty, and roundcubemail), openSUSE (dbus-1, gegl, mxml, open-vm-tools, partclone, qbittorrent, tcpreplay, and xtrabackup), and Ubuntu (eject, gst-plugins-base0.10, gst-plugins-base1.0, and gst-plugins-good0.10, gst-plugins-good1.0).
DAX is the mechanism that enables direct access to files stored in
persistent memory arrays without the need to copy the data through the page
cache. At the 2017 Linux Storage, Filesystem, and Memory-Management
Summit, Ross Zwisler led a plenary session on the future of DAX. Development in
this area offers a number of interesting trade-offs between data safety and
enabling the highest performance.
DragonFly BSD 4.8 has been released
version 4.8 brings EFI boot support in the installer, further speed
improvements in the kernel, a new NVMe driver, a new eMMC driver, and Intel
video driver updates." DragonFly is an independent BSD variant,
perhaps best known for the HAMMER filesystem.
The Free Software Foundation has announced
of the 2016 Free Software Awards. The Award for Projects
of Social Benefit went to SecureDrop
and the Award for the Advancement of Free Software went to Alexandre Oliva
. "SecureDrop is an anonymous whistleblowing platform used by major news organizations and maintained by Freedom of the Press Foundation. Originally written by the late Aaron Swartz with assistance from Kevin Poulsen and James Dolan, the free software platform was designed to facilitate private and anonymous conversations and secure document transfer between journalists and sensitive sources."
Stable kernels 4.10.6
, and 4.4.57
have been released. All of them
contain important fixes and users should upgrade.
Security updates have been issued by Debian (apt-cacher, jbig2dec, libplist, python3.2, tnef, and xrdp), Fedora (firefox, mbedtls, and sane-backends), Mageia (flash-player-plugin, freetype2, glibc, kernel, kernel-linus, kernel-tmb, libquicktime, libwmf, and tnef), and Ubuntu (thunderbird).
kernel prepatch is out for
testing. "So on the whole things look fine. There's changes all
over, and in mostly the usual proportions. Some core kernel code shows up
in the diffstat slightly more than it usually does - we had an audit fix
and a bpf hashmap fix, but on the whole it all looks very regular."
In the memory-management subsystem, the term "mapping" refers to the
connection between pages in memory and their backing store — the file that
represents them on disk. One of the fundamental assumptions in the
kernel is that a given page in the page cache belongs to exactly one mapping.
But, as Miklos Szeredi explained in a plenary session at the 2017 Linux
Storage, Filesystem, and Memory-Management Summit, there are situations
where it would be desirable to associate the same page with multiple
mappings. Achieving this goal may not be easy, though.
Click below (subscribers only) for continuing coverage from LSFMM 2017
The Eudyptula Challenge
series of programming exercises for the Linux kernel. It starts from a
very basic "Hello world" kernel module, moves up in complexity to getting
patches accepted into the main kernel. The challenge
will be closed to new participants in a few months, when 20,000 people have
signed up. LWN covered
the Eudyptula Challenge in May 2014,
when it was fairly new. At this time over 19,000 people have signed up and
only 149 have finished.
Security updates have been issued by Arch Linux (libpurple), Debian (audiofile, cgiemail, and imagemagick), Fedora (cloud-init, empathy, and mupdf), Mageia (firefox and thunderbird), Scientific Linux (icoutils and openjpeg), Slackware (mcabber and samba), and Ubuntu (eglibc).
Back in 2015, the OpenSSL project announced
intent to move away from its rather quirky license. Now it has announced
change is moving forward
. "After careful review, consultation
with other projects, and input from the Core Infrastructure Initiative and
legal counsel from the SFLC, the OpenSSL team decided to relicense the code
under the widely-used ASLv2." It is worth noting that this change
and the way it is being pursued are not universally popular, in the OpenBSD camp, at least