3.10

3.9

Btrfs:
 native RAID 5 and 6 support.

LVM:
 dm-cache(SSD caching) (DOC: cache-policies.txt cache.txt) <-- user mode: flashcache and bcache

Net:
  SO_REUSEPORT
  (multiple web server processes or threads to open individual sockets to listen on port 80)

3.8

加入新的 FS: F2FS (Flash-Friendly File System)

Btrfs
 新加 "replace" feature

Ext4
 to store files that only consist of a few bytes together with the inode
 SEEK_DATA and SEEK_HOLE (backup or copy tools to detect, and omit, empty areas in sparse files)

 
Networking:
 The Berkeley packet filter (BPF), used by sniffer tools such as tcpdump, can now be used to filter VLAN tags.

 
Virtualisation

balloon driver for Hyper-V
kmem extension

3.7

btrfs

• up to 65,536 hardlinks to one file
• Btrfs can now deallocate memory areas within files
• improves fsync performance

• In ATA devices, the cache_type sysfs device file  can now be used to switch between
  the write-through and write-back cache behaviours.
• The Libata subsystem supports "Aggressive SATA device sleep"
• The block layer offers the "WRITE SAME" command

3.6

• kvm: VFIO( Virtual Function I/O ) (passing through of PCI and PCIe devices)
• kvm: Qemu: storage migration (allows blocks to be copied from one running QEMU image to another)
• kvm: Qemu: block commits (snapshot deletion)
• Btrfs: now supports quotas for subvolumes
• Btrfs: userspace programs to determine the difference between two snapshots
• ext4:  no longer stores quota information in visible files
• symlink and hardlink restrictions to the Linux VFS
• save swap files to NFS shares
• virtio-scsi: now supports hotplugging
   

3.5

• ext4   <--- checksums to metadata (mkfs -O metadata_csum) 可惜沒有修復能力 ...
• Uprobes - user-space probes(performance probes) (no need to restart the program or modify the binaries. )
• TCP connection repair (Putting the socket in a "repair" mode)
  (relocate a entire network connection from one host to another transparently for the remote end)
• TCP Early Retransmit(/proc/sys/net/ipv4/tcp_early_retrans)
• btrfs   <--- CRC & I/O failure statistics (btrfs device stats)

3.4

• Btrfs           <--- btrfs-restore, file system within a VM
• mdadm      <--- hot-replace
• read-only support for the QNX4
• kvm: virtio-scsi

3.3

• Open vSwitch
• RDMA (SCSI Remote Direct Memory Access) Target driver
• Adaptive RED (Random Early Detection)
• teaming device (802.1AX)
• cgroups      <--- TCP buffer limits, Network priority control group
• ext4           <--- online resize
• EFI boot support (Both BIOS and EFI boot loaders can still load and run the same bzImage)
• PMU v2 (Performance Monitoring Unit)  for KVM
• MD: hot replace

3.2

• ext4                    <--- block sizes bigger than 4KB and up to 1MB
• btrfs                    <--- Manual inspection of the filesystem (btrfs inspect <inode/logical>  <n> /mnt)
                             <--- mount option: "t -o subvol=path/to/subvol/you/want"
                             <--- mount option: "-o recovery" 
• DM layer              <---thin provisioning
• CPU bandwidth control
• I/O-less dirty throttling
• TCP Proportional Rate Reduction
• perf top                <--- explore the assembly code arbitrarily deep
• syscalls - Cross memory attach     <---allow to r/w f/t another processes address space)
• B.A.T.M.A.N. ad hoc networking

3.1

• Dynamic writeback throttling
• ext3 mout opt: barrier=0    <--- disks provide a "cache flush" instruction that the OS uses when it needs (barrier)
• cpupowerutils
• MD layer(software raid) Bad block management
• ipv4 microoptimization: save cpu cycles from check_leaf()
• Strict CPU affinity, by writing the value 2 to /sys/block/<bdev>/queue/rq_affinity
• KVM: Nested VMX (Intel virtualization) support

3.0

• btrfs    <--- Automatic defragmentation (-o autodefrag)
• btrfs    <---- Scrub
• btrfs    <---- delayed b+ tree insertions or deletions
• Wake on WLAN (ACPI S3 suspend)
• ext4   <--- Punching holes (portion of the file can be marked as unwanted)
• Net     <--- pkt_sched: QFQ - quick fair queue scheduler
• Cache xattr security drop check for write
• cgroup - Memory   <--- Reclaim memory from nodes in round-robin order
                               <--- pagefault count
• syscall   <--- sendmmsg(): batching of sendmsg() calls

詳見:

http://kernelnewbies.org/Linux_3.2