Kernel Space: Rollercoaster, Memory Management, Linux 5.16, and More

• Rollercoaster: group messaging for mix networks [LWN.net]

  Even encrypted data sent on the internet leaves some footprints—metadata about where packets originate, where they are bound, and when they are sent. Mix networks are meant to hide that metadata by routing packets through various intermediate nodes to try to thwart the traffic analysis used by nation-state-level adversaries to identify "opponents" of various kinds. Tor is perhaps the best-known mix network, but there are others that make different tradeoffs to increase the security of their users. Rollercoaster is a recently announced mechanism that extends the functionality of mix networks in order to more efficiently communicate among groups. Tor uses multiple relay nodes, each of which only knows its predecessor and the node to pass the message on to. It relies on the difficulty of tracking messages through that path, but a sophisticated and well-placed adversary can do various kinds of traffic analysis to potentially match up traffic between two endpoints, thus drawing conclusions about the participants in the communication. To minimize latency, Tor nodes forward packets as quickly as they can, which may help eavesdroppers correlate the traffic. The Rollercoaster developers, Daniel Hugenroth, Martin Kleppmann, and Alastair R. Beresford from the University of Cambridge, used the Loopix mix network to validate their work. Loopix is different from Tor in that sacrifices latency in order to make traffic analysis even more difficult. The client endpoints in such a mix network send fixed-sized packets at a fixed rate; if there is no outbound traffic, a cover packet is sent that is indistinguishable from normal traffic. The packets are sent to the relay nodes, which independently delay each packet before passing it on to the next relay. All of that makes it much more difficult to correlate the traffic and identify communicating endpoints.

• Some upcoming memory-management patches [LWN.net]

  The memory-management subsystem remains one of the most complex parts of the kernel, with an ongoing reliance on various heuristics for performance. It is thus not surprising that developers continue to try to improve its functionality. A number of memory-management patches are currently in circulation; read on for a look at the freeing of page-table pages, kvmalloc() flags, memory clearing, and NUMA "home nodes".

• 5.16 Merge window, part 2 [LWN.net]

  Linus Torvalds released 5.16-rc1 and ended the 5.16 merge window on November 14, as expected. At that point, 12,321 non-merge changesets had been pulled into the mainline; about 5,500 since our summary of the first half of the merge window was written. As is usually the case, the patch mix in the latter part of the merge window tended more toward fixes, but there were a number other changes as well.

• Intel SGX2 / Enclave Dynamic Memory Management Patches Posted For Linux - Phoronix

  While Intel's Software Guard Extensions (SGX) functionality has been present in CPUs going back to Skylake, it took until last year with Linux 5.11 for SGX support to finally be mainlined and required more than 40 rounds of review/revisions. Finally today Intel posted patches for bringing up SGX2 as the next iteration of Software Guard Extensions and already found in shipping processors. Intel SGX is about defining private memory regions "enclaves" that are encrypted and cannot be read/used by any other processes or the host. SGX can be used for some interesting secure computing scenarios but the belated kernel support as well as various possible security vulnerabilities / attacks have rather limited its scope so far. Earlier this year building off the prior SGX support in Linux 5.11, SGX was brought for KVM guest support in v5.13.

Cutelyst 3.2 and ASql 0.50 are out!

Cutelyst the Qt Web Framework got a new release...

today's leftovers

• PostgreSQL: DB Comparer for PostgreSQL version 5.0 released

  EMS Software Development (SQLManager.net) is pleased to announce the new major version of DB Comparer for PostgreSQL - the powerful tool for comparing PostgreSQL databases and discovering differences in their structure.

• Pocket’s state-by-state guide to the most popular articles in 2021

  We’re just going to say it: it feels a little bit weird to wrap up 2021 because this year feels like three years in one and an extension of 2020 simultaneously. At some point in the near future, 2020 and 2021 will be studied in history books. While we can’t predict what the history books will say, we can analyze what defined this year for us. We do just that in Pocket’s Best of 2021 — the most-saved, -read and -shared articles by Pocket readers, spanning culture, science, tech and more. As we analyzed the winning articles, we wondered what we might learn if we looked at the data state by state.

• Celebrating Pocket’s Best of 2021

  We aren’t the only ones putting out Top 10 content lists or Year in Reviews, but we’d argue these lists are different from the rest — a cut above. Pocket readers are a discerning bunch: they gravitate to fascinating long reads that deeply immerse readers in a story or subject; explainers that demystify complex or poorly understood topics; big ideas that challenge us to think and maybe even act differently; and great advice for all facets of life. You’ll find must-read examples of all of these inside these eclectic Best of 2021 collections, from dozens of trustworthy and diverse publications. The stories people save most to Pocket often provide a fascinating window into what’s occupying our collective attention each year. In 2019, the most-saved article on Pocket examined how modern economic precarity has turned millennials into the burnout generation. In 2020, the most-read article was a probing and prescient examination of how the Covid-19 pandemic might end.

• Chromium Blog: Faster Chrome - Let The Compiler do the work

  Chrome is fast, but there's always room for improvement. Often, that's achieved by carefully crafting the algorithms that make up Chrome. But there's a lot of Chrome, so why not let computers do at least some part of our work? In this installment of The Fast And the Curious, we'll show you several changes in how we build Chrome to achieve a 25.8% higher score on Speedometer on Windows and a 22.0% increase in browser responsiveness. [...] It turns out that the compiler can make even more use of that profile data for PGO. (Not a surprise - once you know where the slow spots are, exactly, you can do a lot to improve!). To make use of that, and enable further improvements, LLVM has something called the "new pass manager". In a nutshell, it's a new way to run optimizations within LLVM, and it helps a lot with PGO. For much more detail, I'd suggest reading the LLVM blog post.

• LibrePlanet 2022 will be held March 19-20, CFS extended to December 15th

  Have you submitted a talk for LibrePlanet 2022 yet? For those unsure if they could make it to the virtual event, we have now set the dates: March 19 and 20, 2022! We have also extended the Call for Sessions (CfS) until Wednesday, December 15, 2021 at 10:00 EST (15:00 UTC). This gives us time to get a little more organized, and more importantly, gives you the chance to make sure you're a part of LibrePlanet 2022: Living Liberation!

• Apache Month in Review: November 2021

  Welcome to the latest monthly overview of events from the Apache community. Here's a summary of what happened in November...

• What is a managed IT service? | Ubuntu

  Technology is one of the main success factors for any organisation. A few decades ago, when technology (and life) were not as fast-paced as today, IT was more about keeping the lights on and maintaining business as usual operations. Today, the game has massively changed. On the roads that are ever-changing, innovation is what keeps the wheel spinning. If you think that the world is doing enough innovation today, then it would be very interesting to check the recent Growth & Innovation McKinsey report. This report shows that only 6% of executives are satisfied with innovation within their organisations, with the majority not being able to identify how to encourage innovation! So, how is innovation related to managed IT services and the speed at which organisations adopt new technologies? And even more, what is a managed IT service?

• Dead Cells: The Queen and the Sea announced for 2022 | GamingOnLinux

  Developers at Motion Twin / Evil Empire have announced Dead Cells: The Queen and the Sea DLC that will be releasing in early 2022 (Q1) and it has a teaser. The developer has said it will cost $4.99 at release, which will help continue to fund another year of free updates for Dead Cells along with the next project from Motion Twin. The Queen and the Sea finishes the path started with The Bad Seed and Fatal Falls, giving you a new ending to the game.

• PlayStation 3 emulator RPCS3 shows off big game fixes | GamingOnLinux

  RPCS3 continues advancing to truly nail-down the experience of playing classic PlayStation 3 games emulated on modern platforms and a fresh video shows lots of fun. This new update includes various graphical glitch fixes for Uncharted 2 and 3, The Last of Us and multiple Ratchet & Clank games. Not only that, their team also worked on uncapping the framerates in Tools of Destruction, Quest for Booty, and A Crack in Time with other games in the Ratchet & Clank series being able to have no in-game limit as well.