"August 2001 stream" EXPERIMENTAL downloads

If you download any software from this web site please be aware of the Warranty Disclaimer and Limitation of Liabilities.

This page contains the "August 2001 stream" (kernel version 2.4.7 and 2.4.17 and related) experimental downloads

Experimental code drops only have limited testing and may not be installed or function in all environments. These patches need not be compatible with other patches on developerWorks for Linux for S/390 either.

The purpose of experimental code drops is early publication of on-going efforts at IBM to allow for

This page may also be used to "submit" code into the development streams of open source projects.

Warning You may not use experimental patches on a production system or on any system that may get authority over a production system or access to data of a production system. Disregarding this rule may result in severe data loss.

Experimental patches eventually disappear as they will be included in a following release unless proven wrong or replaced by better code.

No Linux kernel 2.4.17 experimental downloads available.

z90crypt OCO module (64-bit) [2002-01-21] (superseded)

Patch for "order 2 allocation relief" [2001-12-12] (superseded)

Description:
Order 2 allocation relief.
Symptom:
Under stress and after long uptimes of a 64 bit system the error message "__alloc_pages: 2-order allocation failed." appears and either the fork of a new process fails or an active process dies.
Problem:
The order 2 allocation problem is based in the size of the region and segment tables as defined by the zSeries architecture. A full region or segment table in 64 bit mode takes 16 KB of contiguous real memory. The page allocation routines do not guarantee that a higher order allocation will succeed due to memory fragmentation.
Solution:
The order 2 allocation fix is supposed to reduce the number of order 2 allocations for the region and segment tables to a minimum. To do so it uses a feature of the architecture that allows to create incomplete region and segment tables. In almost all cases a process does not need full region or segment tables. If a full region or segment table is needed it is reallocated to the full size.

Important notices:

To create the complete linux kernel sources, the following patches need to be applied in sequence:

linux-2.4.7.tar.gz (GNU)
+ linux-2.4.7-s390.diff (IBM)
+ linux-2.4.7-s390-1.diff (IBM)
+ linux-2.4.7-s390-2.diff (IBM)
+ linux-2.4.7-s390-3.diff (IBM)
+ linux-2.4.7-s390-4.diff (IBM)
+ linux-2.4.7-order2-2.diff (IBM)

Experimental OCO modules (64-bit) for "Order 2 allocation" patch [2001-11-23] (superseded)

The following experimental 64-bit OCO modules are required for a 64-bit kernel with the 2001-11-09 patch for "Order 2 allocation relief" applied.

These experimental 64-bit modules are functionally equivalent to the 2001-11-23 recommended modules.

Patch for "order 2 allocation relief" [2001-11-09] (superseded)

This patch contains the following linux kernel bug fixes:

Description:
Order 2 allocation relief.
Symptom:
Under stress and after long uptimes of a 64 bit system the error message "__alloc_pages: 2-order allocation failed." appears and either the fork of a new process fails or an active process dies.
Problem:
The order 2 allocation problem is based in the size of the region and segment tables as defined by the zSeries architecture. A full region or segment table in 64 bit mode takes 16 KB of contiguous real memory. The page allocation routines do not guarantee that a higher order allocation will succeed due to memory fragmentation.
Solution:
The order 2 allocation fix is supposed to reduce the number of order 2 allocations for the region and segment tables to a minimum. To do so it uses a feature of the architecture that allows to create incomplete region and segment tables. In almost all cases a process does not need full region or segment tables. If a full region or segment table is needed it is reallocated to the full size.

Important notices:

To create the complete linux kernel sources, the following patches need to be applied in sequence:

linux-2.4.7.tar.gz (GNU)
+ linux-2.4.7-s390.diff (IBM)
+ linux-2.4.7-s390-1.diff (IBM)
+ linux-2.4.7-s390-2.diff (IBM)
+ linux-2.4.7-s390-3.diff (IBM)
+ linux-2.4.7-order2.diff (IBM)

Experimental OCO modules (64-bit) for "Order 2 allocation" patch [2001-11-09] (superseded)

The following experimental 64-bit OCO modules are required for a 64-bit kernel with the 2001-11-09 patch for "Order 2 allocation relief" applied.
These experimental 64-bit modules are functionally equivalent to the 2001-11-09 recommended modules.

Experimental OCO modules (31-bit) [2001-11-09] (superseded)

Contact the IBM team

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