Kernel Report

-- Jonathan Corbet

This is a rough dump of notes taken from the Kernel Report at the linux.conf.au on Wednesday (30 Jan 2008). Feel free to edit any inaccuracies.

Aprilish 2.6.25

• big device
• real time scheduling
• dynamic tick
• latencytop
• ext4
• IPv6/IPSEC
• controller-area networks -- by Volkswagon
• network namespace support

scalability

1024 processors works well 4096 needs work

small systems

problems getting these ppl to participate

Filesystems

bigger hdds, but not that much faster

chunkfs / tilefs -- Val Hansen - see Chunkfs on Thursday

Btrfs -- Chris Mason

• extent based
• subvolumes and snapshotting
• chksumming
• online fsck possible
• offline fsck fast by design
• seek optimization

ext4

• 48bit block numbers
• extents
• nanosec timestamps
• prealloc /delayed alloc
• journal chksums

• LFS > 2TB

• online defragmentation

LogFS

• new flash-orientated fs
• onmedia dir tree
• "wandering tree" log
• strong performance

see also ubifs

virtualism

in kernel now... solved

• Xen
• Lguest
• KVM

containers

• lightweight virtualism
• share the host kernel
• have different filesystems
• indirection for all global resources: processes

near term:

pid namespaces network namespaces overall control

cpu scheduling completely fair scheduler group scheduling in 2.6.24

syslets asynch system calls

if a sys call blocks: continue in new thread, collect results later api still being worked out

real time hard realtime full tickless operation

new system calls: revoke() remove all access to a file indirect() additional params for existing calls hijack() for containers, enter the context of another process

hardware

wireless: mac80211 stack ath5k for 2.6.25

video

• Intel: supported
• ATI: R200, R300 well supported
• nvidia: no support, nouveau.freedesktop.org - reverse eng

power management powertop

tracing

dtrace envy, systemtap, lttng - someday

Security

• SELinux - default

• alternatives: AppArmour, SMACK, TOMOYO Linux