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Wednesday, May 1st, 2019
| Time |
Event |
| 3:08a |
[$] The state of system observability with BPF
The 2019 version of the Linux Storage, Filesystem, and Memory-Management
Summit opened with a plenary talk by Brendan Gregg on observing the state
of Linux systems using BPF. It is, he said, an exciting time; the
BPF-based "superpowers" being added to the kernel are growing in capability and
maturity. It is now possible to ask many questions about what is happening
in a production Linux system without the need for kernel modifications or
even basic debugging information. | | 3:06p |
Security updates for Wednesday
Security updates have been issued by Fedora (libmediainfo, php-horde-horde, and php-horde-turba), SUSE (hostinfo, supportutils, libjpeg-turbo, and openssl), and Ubuntu (dovecot, libpng1.6, and memcached). | | 4:06p |
[$] Toward a reverse splice() The splice()system call is, at its core, a write operation; it attempts to implement zero-copy I/O by moving pages from a pipe to a file. At the 2019 Linux Storage, Filesystem, and Memory-Management Summit, Miklos Szeredi described a nascent idea for rsplice() — a "reverse splice" system call. There were not a lot of definitive outcomes from this discussion, but one thing was clear: rsplice() needs a much better description (and some code posted) before the development community can begin to form an opinion on it. | | 6:04p |
[$] Memory encryption issues
"People think that memory encryption sounds really cool; it will make my
system more secure so I want it". At least, that is how Dave Hansen
characterized the situation at the beginning of a session on the topic
during the memory-management track at the 2019 Linux Storage, Filesystem,
and Memory-Management Summit. This session, also led by Kirill Shutemov,
covered a number of aspects of the memory-encryption problem on Intel
processors and beyond. One clear outcome of the discussion was also raised
by Hansen at the beginning: users of memory encryption need to think hard
about where that extra security is actually coming from. | | 7:08p |
[$] Android memory management
The Android system is designed to provide a responsive user experience on
systems that, in a relative sense at least, have limited amounts of
CPU and memory. Doing so requires a number of techniques, including
regular use of
a low-memory process killer, that are not seen elsewhere. In a
memory-management-track session at the 2019 Linux Storage, Filesystem, and
Memory-Management Summit, Suren Baghdasaryan covered a number of issues
related to how Android ensures that interactive processes have enough
memory to get their jobs done. | | 7:30p |
[$] Containers and address space separation James Bottomley began his talk at the 2019 Linux Storage, Filesystem, and Memory-Management Summit (LSFMM) by noting that the main opposition to his ideas was not present at the summit, which was likely to mean the ideas got a much easier reception than they would have otherwise. In particular, Peter Zijlstra and Ingo Molnar expressed some strong reservations to the work that Bottomley's colleague Mike Rapoport postedrecently; none of those three were in attendance at LSFMM. The idea is to use address spaces to reduce the attack surface available to virtual machines (VMs) and containers such that kernel bugs of various sorts have less reach on multi-tenant systems. |
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