Usefulness of Swap Explained

Chris Down explains how swap’s main role is being the missing backing store for anonymous (i.e. allocated by malloc) pages. While all other kinds of data (e.g. paged in files) can be reclaimed easily and later reloaded, because their “source of truth” is elsewhere. There’s no such source for anonymous pages hence these pages can “never” be reclaimed unless there’s swap space available (even if those pages aren’t “hot”).

Linux has historically had poor swap (and by extension OOM) handling with few and imprecise means for configuration. Chris describes the behavior of a machine with and without swap in different scenarios of memory contention. He thinks that poor swap performance is caused by having a poor measure “memory pressure.” He explains how work on cgroup v2 might give the kernel (and thus admins) better measures for memory pressure and knobs for dealing with it.

Silicon Valley or Soviet Union

This made my day.

In Support of Strong Encryption


IEEE supports the use of unfettered strong encryption to protect confidentiality and integrity of data and communications. We oppose efforts by governments to restrict the use of strong encryption and/or to mandate exceptional access mechanisms such as “backdoors” or “key escrow schemes” in order to facilitate government access to encrypted data. Governments have legitimate law enforcement and national security interests. IEEE believes that mandating the intentional creation of backdoors or escrow schemes – no matter how well intentioned – does not serve those interests well and will lead to the creation of vulnerabilities that would result in unforeseen effects as well as some predictable negative consequences.
— IEEE Position Statement

Why hardware + software is cheaper than hardware alone

Thomas Dullien of Google’s Project Zero on why security suffers because it’s actually cheaper to build more complex things (i.e. ship some piece of hardware with a general purpose processor and define features in software instead of using a purpose-built chip).

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