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MF51704 - OSP-WAIT TASK PREEMPTION LEFT DISABLED - OTHER TASKS COULD N

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Abstract

OSP-WAIT TASK PREEMPTION LEFT DISABLED - OTHER TASKS COULD N


Pre/Co-Requisite PTF / Fix List

REQ  LICENSED      PTF/FIX  LEVEL

TYPE PROGRAM  REL  NUMBER   MIN/MAX  OPTION
---- -------- ---  -------  -------  ------
NONE



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APAR Error Description / Circumvention

-----------------------------------------------
IOCMxxxxxx task had a positive 'no preemption count' when it
shouldn't have. This kept all other tasks in the system from
being dispatched. The count allows the task to run as long as it
wants; forever, in this case. Code has been identified that
could leave the counts non-zero. Service Keywords:
QuPoolCodeHighUse IoCommNativeNuc2HighUse CPU

CORRECTION FOR APAR MA40227 :
-----------------------------
A problem has been identified in the SkRefCount lock function.
In some cases, it may disable task preemption more than once
while attempting to obtain an exclusive lock and reenable task
preemption only once when unlocking. This would result in a
non-zero 'no preemption count'. The SkRefCount lock is used when
new passive (inbound) TCP connections are established. This
processing occurs in the IOCMxxxxx tasks, so could explain the
positive 'no preemption count' in these tasks.

The SkRefCount lock processing has been corrected so that a lock
and unlock of the SkRefCount will disable preemption once and
reenable preemption once.

CIRCUMVENTION FOR APAR MA40227 :
--------------------------------
None.


Activation Instructions


None.




Special Instructions


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THIS PTF CAN BE APPLIED IMMEDIATE OR DELAYED.



Supersedes

PTF/FIX NO(S).  APAR TITLE LINE
--------------  ------------------------------------------------------------
     NONE

Summary Information

System..............................i
Models..............................
Release.............................V7R1M0
Licensed Program...............5770999
APAR Fixed..........................View details for APAR MA40227
Superseded by:......................
Recompile...........................N
Library.............................QSYS
MRI Feature ........................NONE
Cum Level...........................C1116710


System i Support

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Document Information

Modified date:
13 November 2010