Linux 3.15 [https://lkml.org/lkml/2014/6/8/70 has been released] on Sun, 8 Jun

Summary: This release resumes much faster in systems with hard disks, it adds support for cross-renaming two files atomically, it adds new [http://man7.org/linux/man-pages/man2/fallocate.2.html fallocate(2)] modes that allow to remove the range of a file or set it to zero, it adds a new file locking API, the memory management adapts better to working set size changes, it improves FUSE write performance, it adds support for the LZ4 algorithm in zram, it allows to load 64-bit kernels from 32-bit EFI systems, it adds support for AVX-512 vector instructions that will be added in upcoming Intel CPUs, and it adds new drivers and many other small improvements.

TableOfContents()

1. Prominent features

1.1. Faster resume from power suspend in systems with hard disk drives

Resuming a system from suspend used to take a long time in systems with traditional hard disk drives, because the system blocks the resume process until the hard disk drive finish powering up. In this release, commands are sent to the hard disk asynchronously, so the entire resuming process isn't paused by the hard disk. The end result is that systems with hard disks will resume several seconds faster with this Linux release.

For more details, see this [https://01.org/suspendresume/blogs/tebrandt/2013/hard-disk-resume-optimization-simpler-approach blog entry]

Code: [https://git.kernel.org/linus/200421a80f6e0a9e39d698944cc35cba103eb6ce commit 1], [https://git.kernel.org/linus/3c31b52f96f7b559d950b16113c0f68c72a1985e 2]

1.2. Improved working set size detection

When there is not enough room for all memory in RAM, the Linux kernel is in charge of deciding which memory must be kept in RAM, and which must be sent to swap or discarded. In order to make good decisions, it is necessary to track which memory is most used and deserves to be kept in RAM, and which memory is not used often and can be evicted. The way the Linux kernel does this is by keeping an "inactive" and "active" list, when some data needs to be moved to RAM its memory is marked as active. As more and more memory gets used, the active list gets filled and the less used memory is moved to the inactive list.

The problem with this algorithm is to know how big must be each list. Linux used to have a policy of not allowing the active list to grow larger than the inactive, but this approach caused problems. In this release, Linux does more advanced tracking of how memory gets used and can balance better the size of the lists, which makes Linux perform better in certain workloads, adapt better to workload size changes, and creates a foundation to build improved policies in the future.

For more details, read this recommended link: [http://lwn.net/Articles/495543/ Better active/inactive list balancing]

[https://git.kernel.org/linus/e7b563bb2a6f4d974208da46200784b9c5b5a47e commit 1], [https://git.kernel.org/linus/449dd6984d0e47643c04c807f609dd56d48d5bcc 2], [https://git.kernel.org/linus/d26914d11751b23ca2e8747725f2cae10c2f2c1b 3], [https://git.kernel.org/linus/6dbaf22ce1f1dfba33313198eb5bd989ae76dd87 4], [https://git.kernel.org/linus/a528910e12ec7ee203095eb1711468a66b9b60b0 5]

1.3. EFI 64-bit kernels can be booted from 32-bit firmware

Most modern x86 CPUs are 64-bit, but many modern systems ship with a 32-bit EFI implementation. This didn't allow to boot a Linux 64-bit EFI kernel from these 32-bit EFI systems. This limitation has been removed, a 64-bit kernel can be booted on 32-bit firmware that runs on 64-bit CPUs (note that it is not possible to boot a mixed-mode enabled kernel via the EFI boot stub - a bootloader that supports the EFI handover protocol must be used)

Code: [https://git.kernel.org/linus/0154416a71c2a84c3746c8dd8ed25287e36934d3 commit 1], [https://git.kernel.org/linus/4f9dbcfc40299ddaa780fe8c1cd74998c1be3af5 2], [https://git.kernel.org/linus/54b52d87268034859191d671505bb1cfce6bd74d 3], [https://git.kernel.org/linus/099240ac111aac454962e6399c0cc51d1511504a 4], [https://git.kernel.org/linus/b8ff87a6158886771677e6dc8139bac6e3cba717 5], [https://git.kernel.org/linus/e10848a26a962e404ac00c897dfe54f14290806d 6], [https://git.kernel.org/linus/18c46461d9e42d398536055f31f58cdcd2c6347e 7], [https://git.kernel.org/linus/9a11040ff962304c1838aa9a9f33be78784eae47 8], [https://git.kernel.org/linus/3f4a7836e33134d4ac34fa7c99788f0c6a79fa1c 9], [https://git.kernel.org/linus/c116e8d60adabfd545a269fccab85e77febc1643 10], [https://git.kernel.org/linus/7d453eee36ae4cf30fc2f2faae54f634c4f863b7 11]

1.4. New file locking scheme: file private locks

Due to some unfortunate history, POSIX locks have very strange and unhelpful semantics: they are dropped whenever the process closes any file descriptor associated with the inode, and locks taken between threads within the same process won't conflict with one another, which renders them useless for synchronization between threads.

This release adds a new type of lock that attempts to address these issues. These locks will conflict with classic POSIX read/write locks, but have semantics that are more like BSD locks with respect to inheritance and behavior on close.

For more documentation and details about the new locking API, read this recommended LWN link: [http://lwn.net/Articles/586904/ File-private POSIX locks]

Code: [https://git.kernel.org/linus/5d50ffd7c31dab47c6b828841ca1ec70a1b40169 commit]

1.5. Faster erasing and zeroing of parts of a file

This release adds two new [http://man7.org/linux/man-pages/man2/fallocate.2.html fallocate(2)] mode flags:

• FALLOC_FL_COLLAPSE_RANGE: Allows to remove a range of a file without leaving holes, improving the performance of these operations that previously needed to be done with workarounds.
• FALLOC_FL_ZERO_RANGE: Allows to set a range of a file to zero, much faster than it would take to do it manually (this functionality was previously available in XFS through the XFS_IOC_ZERO_RANGE ioctl)

In this release, only XFS and ext4 have added support for these new flags, other filesystems will follow in the future.

For more details, read this LWN article: [http://lwn.net/Articles/589260/ Finding the proper scope of a file collapse operation]

Code: [https://git.kernel.org/linus/00f5e61998dd17f5375d9dfc01331f104b83f841 commit 1], [https://git.kernel.org/linus/409332b65d3ed8cfa7a8030f1e9d52f372219642 2], [https://git.kernel.org/linus/9eb79482a97152930b113b51dff530aba9e28c8e 3], [https://git.kernel.org/linus/b8a8684502a0fc852afa0056c6bb2a9273f6fcc0 4], [https://git.kernel.org/linus/e1d8fb88a64c1f8094b9f6c3b6d2d9e6719c970d 5], [https://git.kernel.org/linus/376ba313147b4172f3e8cf620b9fb591f3e8cdfa 6]

1.6. File cross-renaming support

This release adds cross-rename, a variant of rename which exchanges the two files. This allows interesting use cases which were not possible before, for example atomically replacing a directory tree with a symlink. It also allows overlayfs and friends to operate on whiteouts atomically.

For more details, read this LWN article: [http://lwn.net/Articles/569134/ Exchanging two files]

Code: [https://git.kernel.org/linus/520c8b16505236fc82daa352e6c5e73cd9870cff commit], [https://git.kernel.org/linus/da1ce0670c14d8380e423a3239e562a1dc15fa9e commit], [https://git.kernel.org/linus/bd42998a6bcb9b1708dac9ca9876e3d304c16f3d commit]

1.7. zram: LZ4 compression support, improved performance

Zram is a memory compression mechanism added in [http://kernelnewbies.org/Linux_3.14#head-72b295b09fea85de2e80f0b7850048264fed887e Linux 3.14] that is used in Android, Cyanogenmod, Chrome OS, Lubuntu and other projects. In this release zram brings support for the LZ4 compression algorithm, which is better than the current available LZO in some cases.

This release also adds performance improvements to concurrent compression of multiple compression streams, and the ability to switch the compression algorithm in /sys/block/zram0/comp_algorithm

Code: [https://git.kernel.org/linus/e7e1ef439d18f9a21521116ea9f2b976d7230e54 commit 1], [https://git.kernel.org/linus/beca3ec71fe5490ee9237dc42400f50402baf83e 2], [https://git.kernel.org/linus/e46b8a030d76d3c94156c545c3f4c3676d813435 3], [https://git.kernel.org/linus/6e76668e415adf799839f0ab205142ad7002d260 4]

1.8. Intel AVX-512 vector instructions support

[http://en.wikipedia.org/wiki/AVX-512 AVX-512] are 512-bit extensions to the 256-bit Advanced Vector Extensions SIMD instructions for x86 instruction set architecture proposed by Intel, and scheduled to be supported in 2015 with Intel's [http://en.wikipedia.org/wiki/Knights_Landing_(microarchitecture) Knights Landing] processor.

For more details about these extensions, read the [http://download-software.intel.com/sites/default/files/managed/71/2e/319433-017.pdf documentation].

Code: [https://git.kernel.org/linus/918d80a136430aeb23659aa75f8b415090500667 commit]

1.9. FUSE: improved write performance

FUSE can now use cached writeback support to fuse, which improves write throughput.

Code: [https://git.kernel.org/linus/4d99ff8f12eb20c6cde292f185cb1c8c334ba0ed commit]

2. Drivers and architectures

All the driver and architecture-specific changes can be found in the [http://kernelnewbies.org/Linux_3.15-DriversArch Linux_3.15-DriversArch page]

3. Core

• Add generic support for CPU feature based module autoloading [https://git.kernel.org/linus/67bad2fdb754dbef14596c0b5d28b3a12c8dfe84 commit]

• Introduce cancelable MCS lock, it is a simple spinlock with the desirable properties of being fair, and with each CPU trying to acquire the lock spinning on a local variable. It avoids expensive cache bouncings that common test-and-set spinlock implementations incur [https://git.kernel.org/linus/fb0527bd5ea99bfeb2dd91e3c1433ecf745d6b99 commit]

• Permit disabling the obsolete uselib [https://git.kernel.org/linus/69369a7003735d0d8ef22097e27a55a8bad9557a commit] and sys_sysfs syscalls, no longer used by libc [https://git.kernel.org/linus/6af9f7bf3c399e0ab1eee048e13572c6d4e15fe9 commit]

• NUMA: make smarter decisions on NUMA migrations in order to maximize performance of workloads that do not fit in one NUMA node [https://git.kernel.org/linus/10f39042711ba21773763f267b4943a2c66c8bef commit]

• Rework sysfs layout for memcg caches [https://git.kernel.org/linus/9a41707bd3a0811919000daf094e9d50ea65f7da commit]

• tools/vm/page-types.c: 'page-types' can walk over a file's mappings and analyze populated page cache pages mostly without disturbing its state [https://git.kernel.org/linus/65a6a4105f84f961fb219f5acaf05203f7114cf9 commit]

• Show mnt_id in /proc/pid/fdinfo [https://git.kernel.org/linus/49d063cb353265c3af701bab215ac438ca7df36d commit]

• Make /proc/*/pagemap 0400 [https://git.kernel.org/linus/32ed74a4b968a4faff7aaaff557035ce5d5e70ab commit]

• Make /proc/*/{stack,syscall,personality} 0400 [https://git.kernel.org/linus/35a35046e4f9d8849e727b0e0f6edac0ece4ca6e commit]

• Add a lock-torture kernel module [https://git.kernel.org/linus/0af3fe1efa534a43385fe2694c42ffec7a310e46 commit]

4. Memory management

• hugetlb: improve page-fault scalability. The kernel could only handle a single hugetlb page fault at a time. This release allows a better chance of parallelization. This releases reduces the startup time of a 10 Gb Oracle database (with ~5000 faults) from 37.5 seconds to 25.7 seconds compared with previous kernels. Larger workloads will benefit even more [https://git.kernel.org/linus/8382d914ebf72092aa15cdc2a5dcedb2daa0209d commit]

• Per-thread VMA caching; cache last recently used VMA to improve VMA cache hit rate, for more details see the recommended LWN article [http://lwn.net/Articles/589475/ Optimizing VMA caching]. [https://git.kernel.org/linus/615d6e8756c87149f2d4c commit]

• Introduce byte-sized index for the freelist of a slab; microoptimizes some microbenchmarks [https://git.kernel.org/linus/a41adfaa23dfe58d0832e74bef54b98db8dcc774 commit]

• zswap: support multiple swap devices [https://git.kernel.org/linus/60105e1248f571aa3b895cd63bef072ed9d90c77 commit]

• "opportunistic fault around"; for more details see the bottom of [http://lwn.net/Articles/592989/ this] page [https://git.kernel.org/linus/8c6e50b0290c4c708a3e6462729e1e9151a9a7df commit]

1b93d471bca002bd849 commit]

5. Power management

• Speed up resume by resuming runtime-suspended devices later during system suspend [https://git.kernel.org/linus/7cd0602d7836c0056fe9bdab014d5ac5ec5cb291 commit], [https://git.kernel.org/linus/92858c476ec4e99cf0425f05dee109b6a55eb6f8 commit]

• Speed up resume by using asynchronous threads for resume_early [https://git.kernel.org/linus/9e5e7910df824ba02aedd2b5d2ca556426ea6d0b commit], resume_noirq [https://git.kernel.org/linus/76569faa62c46382e080c3e190c66e19515aae1c commit], suspend_late [https://git.kernel.org/linus/de377b3972729f00ee236ae4a97393e282ffe391 commit], suspend_noirq [https://git.kernel.org/linus/28b6fd6e37792b16a56d324841bdb20ab78e4522 commit], acpi_thermal_check [https://git.kernel.org/linus/a59ffb2062df3a5c346dbed931fa1e587fd0f0f3 commit]

• tools/power turbostat: Run on Intel Broadwell [https://git.kernel.org/linus/4e8e863fed2e82278d29c6357de8251adb73acb9 commit]

6. Block layer

• UBI: Read-only block driver on top of UBI volumes [https://git.kernel.org/linus/9d54c8a33eec78289b1b3f6e10874719c27ce0a7 commit]

• Device Mapper: add dm-era target. dm-era is a target that behaves similar to the linear target, and in addition it keeps track of which blocks were written within a user-defined period of time called an 'era'. Use cases include tracking changed blocks for backup software, and partially invalidating the contents of a cache to restore cache coherency after rolling back a vendor snapshot [https://git.kernel.org/linus/eec40579d84873dfb7021eb24c50360f073237c5 commit]

7. File systems

• Btrfs

  • Allow mounting different Btrfs subvolumes with different ro/rw options [https://git.kernel.org/linus/0723a0473fb48a1c93b113a28665b64ce5faf35a commit]

  • Don't bother compress writes smaller than a block that are not inlined [https://git.kernel.org/linus/68bb462d42a963169bf7acbe106aae08c17129a5 commit]

  • Less lock contention when using autodefrag [https://git.kernel.org/linus/f094c9bd3e12ee83e91f4249b600d4d2ac0a4738 commit]

  • Replace the Btrfs async threads with regular kernel workqueues [https://git.kernel.org/linus/a046e9c88b0f46677923864295eac7c92cd962cb commit]

  • Add simple debugfs interface [https://git.kernel.org/linus/1bae30982bc86ab66d61ccb6e22792593b45d44d commit]

• ext3

  • Speedup [http://man7.org/linux/man-pages/man2/sync.2.html sync(2)] [https://git.kernel.org/linus/2299432e1950c9ac0aa649d4617374ea24b6f131 commit]

• ext4

  • Speedup [http://man7.org/linux/man-pages/man2/sync.2.html sync(2)] [https://git.kernel.org/linus/10542c229a4e8e25b40357beea66abe9dacda2c0 commit]

  • jbd2: scalability improvements [https://git.kernel.org/linus/42cf3452d5f5b0817d27c93e4e7d7eab6e89077d commit]

• xfs

  • v5 format is now considered stable [https://git.kernel.org/linus/c99d609a16506602a7398eea7d12b13513f3d889 commit]

  • Add O_TMPFILE support [https://git.kernel.org/linus/99b6436bc29e4f10e4388c27a3e4810191cc4788 commit]

  • Allow appending aio writes [https://git.kernel.org/linus/9862f62faba8c279ac07415a6f610041116fbdc0 commit]

• f2fs

  • introduce large directory support [https://git.kernel.org/linus/3843154598a00408f4214a68bd536fdf27b1df10 commit], [https://git.kernel.org/linus/ab9fa662e4867455f44f4de96d29a7f09cf292c6 commit]

  • throttle the memory footprint with a sysfs entry [https://git.kernel.org/linus/cdfc41c134d48c1923066bcfa6630b94588ad6bc commit]

• nilfs2

  • Add FITRIM ioctl support for nilfs2 [https://git.kernel.org/linus/f9f32c44e7016c61f8c60afbe461fbc7d5a6c7cc commit]

  • Implementation of NILFS_IOCTL_SET_SUINFO ioctl. With this ioctl the segment usage entries in the SUFILE can be updated from userspace [https://git.kernel.org/linus/2cc88f3a5f16ae9a3c8f54de1b2fd4a397b36075 commit]

• GFS2

  • Add meta readahead field in directory entries [https://git.kernel.org/linus/44aaada9d144a46d3de48ad81093f69d17fae96f commit]

• affs

  • add mount option to avoid filename truncates [https://git.kernel.org/linus/8ca577223f75230a746a06f4566c53943f78d5d0 commit]

8. Networking

• Expand BPF internal implementation for faster interpreting, more direct translations into JIT'd code, and much cleaner uses of BPF filtering in non-socket contexts [https://git.kernel.org/linus/bd4cf0ed331a275e9bf5a49e6d0fd55dffc551b8 commit], http://git.kernel.org/linus/9a985cdc5ccb0d557720221d01bd70c19f04bb8c commit]

• Bluetooth

  • Enable Secure Connection [https://git.kernel.org/linus/eac83dc632a7afba72f7084266bc310219486253 commit]

  • Security Level 4, a new strong security requirement that is based around 128-bit equivalent strength for link and encryption keys required using FIPS approved algorithms. Which means that E0, SAFER+ and P-192 are not allowed. Only connections created with P-256 resulting from using Secure Connections support are allowed [https://git.kernel.org/linus/7b5a9241b780ea2f77e71647bc0d3c9708c18ef1 commit], [https://git.kernel.org/linus/7d513e9243afd01df315db45ffe96a6e3688e612 commit], [https://git.kernel.org/linus/2c068e0b924c6fabd9a2ac59bc451b4b656cbae3 commit]

  • Add Secure Connection Only Mode [https://git.kernel.org/linus/0ab04a9c0e8e37ca495fb08c8b83615c5f144551 commit]

  • Add management command to use of debug keys [https://git.kernel.org/linus/4e39ac81366583486b857c88656409e56befefdf commit], [https://git.kernel.org/linus/b1de97d8c06d9d8d38e85dc5b0cf3630372e702c commit]

  • Enable LE L2CAP Connection oriented Channel support by default [https://git.kernel.org/linus/9b7655eafeeec9e74e97e9056e820ede8d18093e commit]

  • Add support for Set Privacy command [https://git.kernel.org/linus/62b04cd124cb76ce0b9a6391c6c046c08c1ac8b7 commit]

  • Add support for handling signature resolving keys [https://git.kernel.org/linus/7ee4ea3692f20b87b0e0d3884d5b2d22ec1a2df0 commit]

  • Introduce LE auto connection support [https://git.kernel.org/linus/a4790dbd43d1617b09d57e96494fde5a4b01980a commit], [https://git.kernel.org/linus/9fcb18ef3acb51e54b6bca6d2d803676ac86813d commit]

• wireless

  • Add NAPI support back [https://git.kernel.org/linus/06d181a8fd58031db9c114d920b40d8820380a6e commit]

  • Remove NL80211_FEATURE_P2P_DEVICE_NEEDS_CHANNEL [https://git.kernel.org/linus

  • hwsim: add channel switch support [https://git.kernel.org/linus/0037db63ca71ddbe4473c8e261dcb74d75ff47d2 commit]

  • hwsim: make P2P-Device support optional [https://git.kernel.org/linus/8c66a3d9d951a645861b9ec5751184723c4480ce commit]

• Devices: add busy_poll feature to allow finding out if a device supports busy polling [https://git.kernel.org/linus/d0290214de712150b118a532ded378a29255893b commit]

• af_rxrpc: Add sysctls for configuring RxRPC parameters [https://git.kernel.org/linus/5873c0834f8896aa9da338b941035a2f8b29e99b commit]

• [http://en.wikipedia.org/wiki/B.A.T.M.A.N. BATMAN] protocol

  • Add IPv4 link-local/IPv6-ll-all-nodes multicast support [https://git.kernel.org/linus/ab49886e3da73b6b35ece21006e191910427bb30 commit]

  • Multicast Listener Announcements via Translation Table [https://git.kernel.org/linus/c5caf4ef34e2779c9a90bf4cbb57fbdf57dc8cbc commit], [https://git.kernel.org/linus/60432d756cf06e597ef9da511402dd059b112447 commit]

• bonding: support QinQ for bond arp interval [https://git.kernel.org/linus/fbd929f2dce460456807a51e18d623db3db9f077 commit], [

http://git.kernel.org/linus/e7aceef4ac3180bd93d4c0d3fe23775850b6c31d commit]

• ieee802154: support rf212 and extended mac features [https://git.kernel.org/linus/e035b8addc544c2b4de2f8b0326ba7939abd9541 commit]

• ipsec: add support of limited SA dump [https://git.kernel.org/linus/d3623099d3509fa68fa28235366049dd3156c63a commit]

• New IP_MTU_DISCOVER option IP_PMTUDISC_OMIT [https://git.kernel.org/linus/1b346576359c72bee34b1476b4fc63d77d37b314 commit], new IPV6_MTU_DISCOVER option IPV6_PMTUDISC_OMIT [https://git.kernel.org/linus/0b95227a7ba7e69f795757cd7c839eff0615f2d1 commit]

• netfilter

  • connlimit: use keyed locks for improved performance [https://git.kernel.org/linus/1442e7507dd597cc701b224d3cc9bf1f165e928b commit]

  • connlimit: use rbtree for per-host conntrack obj storage, for improved performance [https://git.kernel.org/linus/7d08487777c8b30dea34790734d708470faaf1e5 commit]

  • conntrack: remove central spinlock nf_conntrack_lock for improved performance [https://git.kernel.org/linus/93bb0ceb75be2fdfa9fc0dd1fb522d9ada515d9c commit]

  • ipset: add forceadd kernel support for hash set types [https://git.kernel.org/linus/07cf8f5ae2657ac495b906c68ff3441ff8ba80ba commit]

  • ipset: add hash:ip,mark data type to ipset [https://git.kernel.org/linus/3b02b56cd5988d569731f6c0c26992296e46b758 commit]

  • ipset: add markmask for hash:ip,mark data type [https://git.kernel.org/linus/4d0e5c076d01d3fb4767a502a9517923fb9a080e commit]

  • nf_tables: accept QUEUE/DROP verdict parameters [https://git.kernel.org/linus/e0abdadcc6e113ed2e22c85b350074487095875b commit]

  • nf_tables: add optional user data area to rules [https://git.kernel.org/linus/0768b3b3d228c5acf2075f40f3d25cda30011d4f commit]

• loopback: sctp: add NETIF_F_SCTP_CSUM to device features [https://git.kernel.org/linus/b17c706987fa6f28bdc1771c8266e7a69e22adcb commit]

• tcp: snmp stats for Fast Open, SYN rtx, and data pkts [https://git.kernel.org/linus/f19c29e3e391a66a273e9afebaf01917245148cd commit]

• Add IPsec protocol multiplexer [https://git.kernel.org/linus/3328715e6c1fcb10cd86b0f3212d18290b7e4463 commit], [https://git.kernel.org/linus/7e14ea1521d9249d9de7f0ea39c9af054745eebd commit]

• vti4/vti6: Support inter address family tunneling. With this patch we can tunnel ipv4/6 traffic via a vti6/4 interface [https://git.kernel.org/linus/78a010cca000aafc6a8503eb2be590a533589a27 commit], [https://git.kernel.org/linus/22e1b23dafa8554ef722454e8b84645820cbbc17 commit]

9. Virtualization

• KVM

  • Allow per-vm capability enablement [https://git.kernel.org/linus/d938dc55225a7212e7f31c5a8571da304cc3de16 commit]

  • PPC: Book3S HV: Add transactional memory support [https://git.kernel.org/linus/e4e38121507a27d2ccc4b28d9e7fc4818a12c44c commit]

  • x86: Add nested virtualization support for MPX [https://git.kernel.org/linus/36be0b9deb23161e9eba962c215aece551113a15 commit]

• Hyper-V

  • Implement the file copy service for Linux guests on Hyper-V ([http://technet.microsoft.com/en-us/library/dn464282.aspx related documentation]) [https://git.kernel.org/linus/01325476d6e46185031be4a9bc6443832dbc807c commit]

  • network: Enable receive side IP checksum offload, send side checksum offload and large send offload [https://git.kernel.org/linus/4a0e70ae5e3858052f6d91564bf3484f1eb91dc7 commit], [https://git.kernel.org/linus/e3d605ed441cf4d113f9a1cf9e1b3f7cabe0d781 commit], [https://git.kernel.org/linus/08cd04bf6d5b14ea90845b596d371bfa33eaba06 commit], [https://git.kernel.org/linus/77bf5487946254798ed7f265877939c703189f1e commit]

  • network: Enable scatter gather I/O [https://git.kernel.org/linus/54a7357f7ac408be4ef4ca82900bd24cb6789f36 commit]

  • hyperv-fb: add support for generation 2 virtual machines. [https://git.kernel.org/linus/9069fd54960304a7c941909cbccdf8df9c42b488 commit]

• Xen

  • xen-netback: Add stat counters for zerocopy [https://git.kernel.org/linus/1bb332af4cd889e4b64dacbf4a793ceb3a70445d commit]

  • xen-netback: Introduce TX grant mapping [https://git.kernel.org/linus/f53c3fe8dad725b014e9c7682720d8e3e2a8a5b3 commit]

  • Add support for MSI message groups [https://git.kernel.org/linus/4892c9b4ada9f9a71a0da7a268f95e988d88064b commit]

• vfio: Multi-IOMMU domain support [https://git.kernel.org/linus/1ef3e2bc04223ff956dc62abaf2dff1f3322a431 commit]

10. Security

• audit: Allow login in non-init namespaces [https://git.kernel.org/linus/543bc6a1a987672b79d6ebe8e2ab10471d8f1047 commit]

• audit: add compat syscall audit support [https://git.kernel.org/linus/4b58841149dcaa500ceba1d5378ae70622fe4899 commit]

• audit: audit /proc/<pid>/cmdline aka proctitle [https://git.kernel.org/linus/3f1c82502c299da08b7b7f08b435212e51166ed9 commit]

• Add driver for Intel Trusted Execution Environment with ME Interface [https://git.kernel.org/linus/92ab513072e73d74fee78062c9935f119339e4de commit]

11. Crypto

• caam - add support for aead null encryption [https://git.kernel.org/linus/ae4a825ffdd6fd769af2667e03070940af1b8368 commit]

• omap-des - Add omap-des driver for OMAP4/AM43xx [https://git.kernel.org/linus/e91aa9d50c3561c4a40b87d1d302db851f07ef31 commit]

• sha - SHA1 transform x86_64 AVX2 [https://git.kernel.org/linus/7c1da8d0d046174a4188b5729d7579abf3d29427 commit]

• tegra - remove driver [https://git.kernel.org/linus/645af2e43705d8c80c9606d5c5e83eda9a1a1a2e commit]

12. Tracing/perf

• Currently the tracers (function, function_graph, irqsoff, etc) can only be used by the top-level tracing directory (not for instances). Allow instances to be able to run a separate tracer apart from the what the top-level tracing is doing [https://git.kernel.org/linus/607e2ea167e56db84387f3ab97e59a862e101cab commit], [https://git.kernel.org/linus/591dffdade9f07692a7dd3ed16830ec24e901ece commit], [https://git.kernel.org/linus/f20a580627f43e73e4e57cb37e3864080ca06088 commit]

• uprobes: Add support for event triggering [https://git.kernel.org/linus/ca3b162021a421b38a9cd7b66555b9b01568dc9d commit]

• perf

  • bench: Add futex-hash microbenchmark [https://git.kernel.org/linus/a043971141f163f9845324a2f83502d15011485d commit], add futex-requeue microbenchmark [https://git.kernel.org/linus/0fb298cf95c0d8119557b7d4657724a146e0622e commit], add futex-wake microbenchmark [https://git.kernel.org/linus/27db78307481dbba68c5f3563c6cb694b25521d9 commit]

  • kvm: introduce --list-cmds for use by scripts [https://git.kernel.org/linus/09a71b97cce70551356b13b668aa1d7d6da84457 commit]

  • probe: Show in what binaries/modules probes are set [https://git.kernel.org/linus/fb226ccd2a6f77be13009edc196da2077800066b commit]

  • Support distro-style debuginfo for uprobe [https://git.kernel.org/linus/a15ad2f5360c821f030c53266ebf467738249c68 commit]

  • Add call-graph option support into .perfconfig [https://git.kernel.org/linus/eb853e80324fa87faf7ae7e1a763ad643f908f2d commit]

  • Disable user-space callchain/stack dumps for function trace events [https://git.kernel.org/linus/6bedfab68666afac1b03f8d62ee037c6ab82fbc5 commit]

[https://git.kernel.org/linus/b9e1ab6d4c0582cad97699285a6b3cf992251b00 commit]

• Disallow user-space callchains for function trace events [https://git.kernel.org/linus/cfa77bc4af2c75c0781ee76cde2dd104c6c8e2b7 commit]

• Disallow user-space stack dumps for function trace events [https://git.kernel.org/linus/63c45f4ba533e9749da16298db53e491c25d805b commit]

• Add trace_clock=<clock> kernel parameter [https://git.kernel.org/linus/e1e232ca6b8faa210e5509f17d55519b4392524f commit]

13. Other news sites that track the changes of this release

• LWN Merge window, [http://lwn.net/Articles/592989/ part 1] and [http://lwn.net/Articles/594864/ part 2]

• Phoronix [http://www.phoronix.com/scan.php?page=news_item&px=MTcwOTY The Top Features Of The Linux 3.15 Kernel]