3.5.1 Matrix Server Release Notes

PolyServe Release Notes 11

• 03_iounmap_deadlock.patch. This patch fixes a deadlock in iounmap()

by changing it to not call ioremap_change_attr() with the vmlist lock

held.

• 04_cfq_entry.patch. This patch corrects a problem with the CFQ I/O

scheduler. Without this patch, when the system is under heavy I/O

load, I/Os can be starved indefinitely and affect operations both

locally and across the cluster. This patch is applied only to the

2.6.9-34.EK kernel. The problem does not exist in the 2.6.9.42.EL

kernel.

Patches for SLES9

The PolyServe Support RPM contains the following kernel patches for the

SLES9 2.6.5-7.244 and 2.6.5-7.252 kernels:

• 00_imapping_race.patch. This patch adds a reference to a filesystem

inode when it is acquired to prevent a race condition that can occur

when the i_mapping pointer is performing sync operations. Without

this patch, the kernel will panic if the race occurs.

• 01_cfq_entry.patch. This patch corrects a problem with the CFQ I/O

scheduler. Without this patch, when the system is under heavy I/O

load, I/Os can be starved indefinitely and affect operations both

locally and across the cluster.

Uninstall Patches

If you do not want to run with a particular patch, you can uninstall it after

you have installed the kernel.

To deinstall a specific patch, run these commands:

# cd /usr/src/linux-<kernel>

# patch -R -p1 < /usr/src/polyserve/<kernel>/patches/<patch_filename>