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Status Functionality already exists
Workspace z/OS
Categories BCP_Storage Management (inc. RSM/ASM/VSM/DIV)
Created by Guest
Created on Sep 4, 2024

RELATED IDEAS

Know how close an AS is to exceeding MEMLIMIT

MEMLIMIT is defined as the limit of private virtual storage that an address space can use above the bar any given time.

But, guarded virtual storage and storage obtained with memlimit=no does not count against the MEMLIMIT.

In SMF is reported SMF30HVO and SMF30HVH.

SMF30HVO: Amount of 64-bit private storage in bytes that is obtained by this step or job. This includes guarded virtual storage and storage obtained with memlimit=NO.

SMF30HVH: High water mark for the number of usable bytes of 64-bit private storage that are obtained by this step or job. This does not include guarded virtual storage but it does include storage obtained with memlimit=NO.

But reviewing this information is not posible to know if an Adress space is near to exceed the specified MEMLIMIT, you don't have control over memlimit=no storage.

Knowing how close you are to exceeding memlimit is valuable.

Would it be possible to implement some variable that represents the amount of 64-bit private storage in bytes that is obtained by one step or job, but that does not include the guarded virtual storage neither the storage obtained with memlimit=no?, or maybe two, one with the value at any given time and another with a High water mark.

In the same way, in the SDSF AS panel (Address Space Memory), the values for "MemObjUsed" and "MemObjHWM" also include storage obtained with memlimit=NO, so there is no variable comparable to memlimit, so it is not possible to know either how close an AS is to exceeding memlimit.

Idea priority Medium
  • Guest
    Reply
    |     Nov 21, 2024
    There are MEMLIMIT notes in the prolog of IARRAX:

    /* MEMLIMIT NOTES: @PLA*/
    /* */
    /* Determining the MEMLIMIT (64-bit High Virtual storage limit): */
    /* How the MEMLIMIT was last set is indicated in RAXLVMemLimS. */
    /* RAXLVMemLim contains the MEMLIMIT in all cases except when */
    /* RAXLVMemLimS = RAXLVSMF in which case the greater of */
    /* RAXLVMemLim and the SMF default, SMCXMEML (in IEESMCX), is */
    /* used. SMCXMEML can change in either direction at any time. */
    /* See the documentation for information on how the MEMLIMIT */
    /* is determined and changed. */
    /* */
    /* Determining virtual storage charged towards the MEMLIMIT: */
    /* (RAXLVABytes - (RAXLVHBytes + RAXLVABytesNoMem)) = the total */
    /* bytes charged toward the MEMLIMIT. The RSM Exclusive or */
    /* RSMAD lock serializes all three values. Holding only the */
    /* local lock can result in an incorrect value. Note that */
    /* there is no MEMLIMIT chargeable storage high water mark. */
    /* RAXLVGBytes is close but included RAXLVABytesNoMem when */
    /* it was computed i.e. (RAXLVABytes - RAXLVHBytes) */

    Does this information help?
    Using the above RAX fields will give you what you need, or are SMF fields needed to satisfy this request?
    1 reply

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