Red Hat ENTERPRISE LINUX 5.5 - TECHNICAL NOTES Manual page 113

RHSA-2010:0178: Important Red Hat Enterprise Linux 5.5 kernel security and bug fix update
• A bug was discovered where closing the lid on an HP6510b caused the system to crash. This was
due to the system failing to run on CPU0. A patch was created to enable ACPI workqueues to run
on CPU0, and this has been tested successfully.
• Some applications (e.g., dump and nfsd) try to improve disk I/O performance by distributing I/
O requests to multiple processes or threads by using the Completely Fair Queuing (CFQ) I/O
scheduler. This application design negatively affected I/O performance, causing a large drop in
performance under certain workloads on real queuing devices.
The kernel can now detect and merge cooperating queues. Further, it can also detect if the queues
stop cooperating, and split them apart again. I/O performance is no longer negatively affected by
using the CFQ scheduler.
• Enable CONFIG_DETECT_HUNG_TASK by default, but disable BOOTPARAM_xx by default
• Only prompt for network configuration when required.
Due to an unexpected side effect of a kernel change in Red Hat Enterprise Linux 5.4, the installer
will prompt for the network configuration, regardless of whether these parameters appear in the
PARM or CONF files.
This flaw was addressed by removing the annotation of cmdline as __initdata. The installer no
longer prompts for network configuration when not required.
1.88.7.1.2. Kernel Platform Enablement
1.88.7.1.2.1. BX-EX/MC Enablement Features
• [Intel 5.5 FEAT] Make suspend-resume work on systems with lots of logical CPUs (Boxboro-EX).
731
BZ#499271
• [Intel 5.5 FEAT] Add ability to access Nehalem uncore config space 504330/539675
• [AMD 5.5 Feat] Support Magny-cours topology 513684/539678
• Red Hat Enterprise Linux 5.5: Power-aware Scheduler changes to support multiple node processors
513685/539680
• Fix kernel panic while booting Red Hat Enterprise Linux 5 32-bit kernel on Magny-cours.
732
BZ#522215
• [Intel 5.5 FEAT] Oprofile: Add support for arch perfmon - kernel component
• EXPERIMENTAL EX/MC: Xen NUMA broken on Magny-cours system Z.
• [Intel 5.5 FEAT] Fix spinlock issue which causes performance impact on large systems.
735
BZ#526078
• EXPERIMENTAL EX/MC: Magny-cours topology fixes.
• EXPERIMENTAL MC/EX: Issue when bringing CPU offline and online with 32-bit kernel.
737
BZ#526770
• EXPERIMENTAL MC/EX: Incorrect memory setup can cause Xen crash.
BZ#485016
727
BZ#427709 BZ#456181
726
728 729
BZ#448130
730
BZ#506898
BZ#526051
736
BZ#526315
BZ#526785
733
BZ#523479
734
738
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