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-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of
Vernooy, C.P. - SPLXM
Sent: Wednesday, November 29, 2006 1:37 PM
To: [email protected]
Subject: Re: What is the correct term these days for region?
-----Original Message-----
From: Vernooy, C.P. - SPLXM
Sent: woensdag 29 november 2006 13:33
To: '[email protected]'
Subject: Re: What is the correct term these days for region?
"Hunkeler Peter , KIUK 3" <[EMAIL PROTECTED]> wrote in
message
news:<[EMAIL PROTECTED]>.
..
> WLM decides if the system can bear another address space.
>
> There is no guarantee a fork() always succeeds. The programmer
> must test the return code and act appropriately. There are a
> number of reason codes related to "resources not available".
>
>
I did some investigations, found SG24-5326-00, which explains that
BPXAS's are WLM server address spaces (fork initiators). WLM maintains a
pool of them to be reused and created when needed. Chapter 5.4 describes
what WLM does when a fork initiator is requested: when one is available
it is resumed and the application continues, when the pool is empty, the
fork request is suspended and WLM creates a new address space and posts
the waiting task.
>Can you point me to docs that describe that WLM takes system resources
>(besides MAXPROCSYS of course) into consideration to decide whether or
>not, or when, to create a new address space?
No, I cannot (easily). It is my understanding but I cannot right now tell
if this is based on some real documentation that I had read back in
OS/390 V1.3/2.4 timeframe when BPXAS were first introduced. Or if it
is a pure assumption of mine out of the believe that WLM will not
endanger system sanity if an additional AS would do so, be it for
a fork() or some other "AS create" request.
This is the list of reasons that a failed fork() may report. It is
definitely more that only MAXPROCUSER.
│ EAGAIN │ The resources required to let another process be │
│ │ created are not available now; or you have │
│ │ already reached the maximum number of processes │
│ │ you are allowed to run. │
│ │ │
│ │ The following reason codes can accompany the │
│ │ return code: JRForkExitRcChildNoStorage, │
│ │ JRForkExitRcParentBadEnv, │
│ │ JRForkExitRcParentNoRoom, JRForkNoAccess, │
│ │ JRForkNoResource, JRForkVsmListTooLarge, │
│ │ JRKernelReady, JRMaxChild, JRMaxProc, JRMaxUIDs, │
│ │ JRNoSecurityProduct, JRNotKey8, and JRWlmWonErr. │
Peter Hunkeler
CREDIT SUISSE
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