kernel bug fix update

Updated kernel packages that fix an MSI performance issue and a driver-specific
network connectivity bug are now available for Red Hat Enterprise Linux 5.3
Extended Update Support.

The kernel packages contain the Linux kernel, the core of the Linux operating
system.

These updated kernel packages provide fixes for the following bugs:

* Previously, Message Signaled Interrupts (MSIs) resulted in PCI bus writes to
mask and unmask the MSI IRQ for a PCI device. These unnecessary PCI bus writes
resulted in the serialization of MSIs, leading to poor performance on systems
with high MSI load. This update adds a new kernel boot parameter, msi_nolock,
which forgoes the PCI bus writes and allows for better simultaneous processing
of MSIs. (BZ#621938)

* Network interface cards (NICs) configured to use both the bnx2 driver and
MSI-X could stop processing interrupts and, consequently, terminate network
connectivity under particularly heavy workloads. This was because the driver
would incorrectly drop writes to unmask the MSI-X vector by the kernel, as the
GRC timeout value for such writes was too short. This update increases the GRC
timeout accordingly, thereby preventing unexpected termination of network
connectivity under these circumstances. (BZ#631811)

Users should upgrade to these updated packages, which contain backported patches
to correct these issues. The system must be rebooted for this update to take
effect.

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
http://kbase.redhat.com/faq/docs/DOC-11259

621938 - Significant MSI performance issue due to redundant interrupt masking [rhel-5.3.z]
631811 - NIC doesn't register packets [rhel-5.3.z]