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Kernel downloads for the "Development stream"

Download Description
upstream kernel 2.6.38 kernel 2.6.38 - upstream with feature descriptions.
linux-2.6.38-s390-message-catalog.tar.gz / MD5 "Development Stream" kernel 2.6.38 - message-catalog (optional)

2011-05-19: kernel 2.6.38 - upstream (feature description)

To download the linux-2.6.38.tar.gz visit: http://www.kernel.org/pub/linux/kernel/v2.6

Since kernel 2.6.35, no more kernel kerntypes-patches (required for work with lcrash, from lkcdutils/LKCD) are provided: Use crash instead of lcrash.

The upstream kernel 2.6.38 contains the following functionality developed by the Linux on System z development team:

kernel: Enabling spinning mutex for Linux on System z
The kernel common code feature spinning mutex is now enabled per default.

It can be disabled with: echo NO_OWNER_SPIN > /sys/kernel/debug/sched_features and enabled again with: echo OWNER_SPIN > /sys/kernel/debug/sched_features

On acquiring a locked mutex, the spinning mutex feature checks if the process holding the mutex is currently running on a CPU. If it is, then the process trying to acquire the mutex will spin in a loop instead of going to sleep.

In general, this will improve performance in situations with many processes and a high mutex lock contention (e.g. I/O traffic), possibly at the cost of a higher CPU load.

cio + dasd: Support for High Performance FICON (HPF) multitrack
High Performance FICON for System z (zHPF) was introduced for z10 in October 2008 (see IBM U.S. Hardware Announcement Letter 108-794) and DS8000 R4.1 (see IBM U.S. Hardware Announcement Letter 108-870) - Linux on System z supports zHPF single track since kernel 2.6.30.

In July 2009, zHPF was extended to multitrack operations with DS8000 R4.3 (see IBM U.S. Hardware Announcement Letter 109-431), reducing overhead and improving performance but limiting transfers to 64k worth of data in a single operation.

Linux on System z can now exploit multi-track with more than 64k per single operation depending on the capabilities of the available hardware (System z and Storage Server).

This support is available only, when running Linux on System z in an LPAR.

cio + dasd: Notification mechanism to inform ccw device drivers about changes to channel paths
This feature adds a notification mechanism to cio to inform ccw device drivers about changes to channel paths, which occurred while the device is online.

The DASD device driver uses these notifications to verify for each path that it meets the requirements, which were established when the device was set online.

dasd: Improve handling of stolen DASD reservation
With this feature, the DASD device driver accepts a policy for handling stolen device reservations.

See Device Drivers, Features, and Commands, Chapter "DASD device driver", section "Handling lost device reservations".

This support is available only, when running Linux on System z in an LPAR.

dasd: Add support for raw ECKD access
This feature extends the DASD device driver to give access to full ECKD tracks including count, key and data fields through a block device interface.

See Device Drivers, Features, and Commands, Chapter "DASD device driver", section "Accessing full ECKD tracks".

qeth: IPv6 support for qetharp
Infrastructure to enable qetharp (in s390-tools 1.13) to show IPv6 entries for HiperSockets (real and GuestLAN) in Layer 3 mode.

See Device Drivers, Features, and Commands, Chapter "Commands for Linux on System z", section "qetharp -Query and modify ARP data".

zcrypt: Support for CEX3A 4096 bit RSA FastPath
The support for current hardware acceleration of RSA encryption and decryption is extended from 2048-bit keys to the new maximum of 4096-bit keys (new with z196) in the zcrypt device driver. This extension is available in ME and in CRT format.

From a user perspective on zcrypt the IOCTLs for ICARSAMODEXPO and ICARSACRT can be used as before: The existing key structs just have to be used with the new, bigger values.

In libica, the functions ica_rsa_mod_expo and ica_rsa_crt can be used as before, except for the new, bigger values for the existing key structs (see libica Programmer's Reference).

CEX3A feature support of RSA keys with 4096 bit length is available only for z196 with MCL N29766.021 since December, 2010.

zfcp: Extend and improve zfcp trace and tools
Implement the new tracing concept for zfcp that moves the dependency of the data analysis from the zfcp driver to zfcpdbf (in s390-tools 1.13).

2011-05-19: "Development Stream" kernel 2.6.38 message catalog (feature - optional patch)

linux-2.6.38-s390-message-catalog.tar.gz / MD5 ... recommended (2011-05-19)

This patch contains:

Kernel message catalog.
Add support for automatic message tags to the printk macro families dev_xyz and pr_xyz. The message tag consists of a component name and a 24 bit hash of the message text. For each message that is documented in the included kernel message catalog a man page can be created with a script (which is included in the patch). The generated man pages contain explanatory text that is intended to help understand the messages.

Note that only s390 specific messages are prepared appropriately and included in the generated message catalog.

This patch is optional as it is very unlikely to be accepted in upstream kernel, but is recommended for all distributions which are built based on the 'Development stream'.

Contact the IBM team

If you want to contact the Linux on z Systems IBM team refer to the Contact the Linux on z Systems IBM team page.

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