A fix is available
APAR status
Closed as program error.
Error description
THIS APAR FIXES THE FOLLOWING LARGE PAGE RELATED PROBLEMS: 1) INSTALLATIONS CAN USE THE LFAREA PARAMETER TO DEFINE THE SIZE OF THEIR LARGE PAGE AREA. ONCE DEFINED, THIS AREA CAN ONLY USED FOR LARGE PAGE REQUESTS. THE ONLY EXCEPTION TO THIS RULE WAS WHEN THE SYSTEM WAS STORAGE CONSTRAINTED. WHEN STORAGE IS CONSTRAINED, RSM WILL BREAK UP A LARGE PAGE INTO 256 4K PAGES IN ORDER TO SATISFY 4K PAGE REQUESTS. WHEN STORAGE IS NO LONGER CONSTRAINED, RSM WILL PERFORM LARGE PAGE COALESCE (I.E. REFORM THE 256 BROKEN UP 4K PAGE BACK INTO 1 LARGE PAGE). THISEMS, APAR WILL FIX VARIOUS LARGE PAGE COALESCE PROBLEMS, INCLUDING FIXING THE LOGIC TO ACTUALLY BREAK UP A LARGE PAGE. 2) RSM RECOVERY DOES NOT PROPERLY CLEAN UP LARGE PAGES OR BROKEN UP LARGE PAGES (I.E. LARGE PAGE SINGLES) DURING TASK/ADDRESS SPACE TERMINATION IF LARGE PAGES OR LARGE PAGE SINGLES ARE ALLOCATED. THIS CAN RESULT IN PERMANENT LOSS OF THESE LARGE PAGES AND LARGE PAGE SINGLES. 3) Virtual storage shortage (or growth) in Subpool 255 Key0. A single getmain (of size x'56AB7210', though this size will vary) from IAXVU +x'A3C' for an LVST. This occurs when IAXV2 calls IARVUELV (IAXVU) to request LVST space, but the IAXVU_Parmlist is not initialized, specifically the IAXVU_EstElems is not set and ends up with an arbitrary (residual) value because the dynamic parmlist in IAXV2 used for IAXVU_Parmlist is also used for several other parmlists for other unrelated macro invocations.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: Users of HBB7750 and up. * **************************************************************** * PROBLEM DESCRIPTION: Various large page coalesce and * * recovery fixes * **************************************************************** * RECOMMENDATION: * **************************************************************** - INSTALLATIONS CAN USE THE LFAREA PARAMETER TO DEFINE THE SIZE OF THEIR LARGE PAGE AREA. ONCE DEFINED, THIS AREA CAN ONLY BE USED FOR LARGE PAGE REQUESTS. THE ONLY EXCEPTION TO THIS RULE WAS WHEN THE SYSTEM WAS STORAGE CONSTRAINED. WHEN STORAGE IS CONSTRAINED, RSM WILL BREAK UP A LARGE PAGE INTO 256 4K PAGES IN ORDER TO SATISFY 4K PAGE REQUESTS. WHEN STORAGE IS NO LONGER CONSTRAINED, RSM WILL PERFORM LARGE PAGE COALESCE (I.E. REFORM THE 256 BROKEN UP 4K PAGE BACK INTO 1 LARGE PAGE). THIS APAR WILL FIX VARIOUS LARGE PAGE COALESCE PROBLEMS, INCLUDING FIXING THE LOGIC TO ACTUALLY BREAK UP A LARGE PAGE. - RSM RECOVERY DOES NOT PROPERLY CLEAN UP LARGE PAGES OR BROKEN UP LARGE PAGES (I.E. LARGE PAGE SINGLES) DURING TASK/ADDRESS SPACE TERMINATION IF LARGE PAGES OR LARGE PAGE SINGLES ARE ALLOCATED. THIS CAN RESULT IN PERMANENT LOSS OF THESE LARGE PAGES AND LARGE PAGE SINGLES. - Virtual storage shortage (or growth) in Subpool 255 Key0. A single getmain (of size x'56AB7210', though this size will vary) from IAXVU +x'A3C' for an LVST. This occurs when IAXV2 calls IARVUELV (IAXVU) to request LVST space, but the IAXVU_Parmlist is not initialized, specifically the IAXVU_EstElems is not set and ends up with an arbitrary (residual) value because the dynamic parmlist in IAXV2 used for IAXVU_Parmlist is also used for several other parmlists for other unrelated macro invocations.
Problem conclusion
The code is changed to implement the various large page coalesce and recovery fixes The following documentation changes are will be made (identified by the change bar '|' in column 1): SA22-7627 z/OS MVS System Commands Chapter 4: MVS System Commands Reference Subtopic: DISPLAY Command Subtopic: Displaying Virtual Storage Information : : Use the DISPLAY VIRTSTOR command to identify the virtual storage configuration. The following information is displayed in message IAR019I: - If DISPLAY VIRTSTOR,HVSHARE is specified: : : | - If DISPLAY VIRTSTOR,LFAREA is specified: | | - Source of LFAREA parameter can be a parmlib member, | operator supplied, or the default. | | - The size of the LFAREA in megabytes, in decimal. | | - The amount of LFAREA that is available in megabytes, | in decimal. | | - The amount of LFAREA that is allocated in megabytes, | in decimal, on behalf of 1M page requests. | | - The amount of LFAREA that is allocated in megabytes, | in decimal, on behalf of 4K page requests. | | - The high water mark for the amount of LFAREA that is | allocated in megabytes, in decimal, on behalf of 1M | page requests. | | - The high water mark for the amount of LFAREA that is | allocated in megabytes, in decimal, on behalf of 4K | page requests. D {VIRTSTOR|VS}, | {HVSHARE|HVCOMMON|LFAREA} : : SA22-7636 z/OS MVS System Messages, Volume 6 (GOS-IEA) Chapter 7: IAR Messages Subtopic: IAR019I : : | Explanation: | | hh.mm.ss DISPLAY VIRTSTOR | SOURCE ={xx|(OP)|DEFAULT} | TOTAL LFAREA = aaaaaaaaaaaM | LFAREA AVAILABLE = bbbbbbbbbbbbbbbM | LFAREA ALLOCATED (1M) = cccccccccccccccM | LFAREA ALLOCATED (4K) = dddddddddddddddM | MAX LFAREA ALLOCATED (1M) = eeeeeeeeeeeeeeeM | MAX LFAREA ALLOCATED (4K) = fffffffffffffffM | | In the message text: | | xx|(OP)|DEFAULT | | The origin of the LFAREA specification can be a | parmlib member, operator supplied, or the default | value. | | hh.mm.ss | | The hour (00-23), minute (00-59), and second (00-59) | that the system issued this message. | | aaaaaaaaaaaaaaaM | | Total size of the LFAREA in megabytes. The amount | displayed will be the amount specified by the | installation (or defaulted to) via the LFAREA | keyword in the IEASYSxx parmlib member. | | bbbbbbbbbbbbbbbM | | Amount, in megabytes, of available 1M pages. | | | cccccccccccccccM | | Amount, in megabytes, of allocated 1M pages | on behalf of 1M page requests. | | dddddddddddddddM | | Amount, in megabytes, of allocated 1M pages | on behalf of 4K page requests. | | eeeeeeeeeeeeeeeM | | High water mark, in megabytes, of allocated 1M pages | on behalf of 1M page requests. | | fffffffffffffffM | | High water mark, in megabytes, of allocated 1M pages | on behalf of 4K page requests. | : : z/OS MVS Data Areas , Vol 5 (MCSCSA-SNAPX) RCE Heading Information RCE MAP See documentation hold for details. z/OS MVS Data Areas , Vol 2 (BCCD-IEFDOKEY) IAXPFTE MAP IAXPFTE Cross reference See documentation hold for details.
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
OA31116
Reported component name
RSM - REAL STOR
Reported component ID
5752SC1CR
Reported release
750
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2009-11-13
Closed date
2010-10-15
Last modified date
2012-05-10
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UA57252 UA57253 UA57254
Modules/Macros
IARRCE IARRIT IAXENDED IAXENDIN IAXFCB IAXGA IAXGT IAXMI IAXMOVEF IAXMT IAXPFTE IAXQL IAXRG IAXRR IAXUA IAXUM IAXVS IAXV2 IAXV7 IAXWB IAXYZ IEECB903
SA227627XX | SA227636XX |
Fix information
Fixed component name
RSM - REAL STOR
Fixed component ID
5752SC1CR
Applicable component levels
R750 PSY UA57252
UP10/10/20 P F010
R760 PSY UA57253
UP10/10/20 P F010
R770 PSY UA57254
UP10/10/20 P F010
Fix is available
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Document Information
Modified date:
09 January 2021