It's only while the SRB is running
> On May 24, 2017, at 11:00 AM, John Arwe <[email protected]> wrote: > > Peter H's version is a first-order match for how the history was related > to me when I first took over ownership of the "old" (pre-WLM) sysevents > approximately two and a half bazillion years ago. > To add a bit: > > - It's the caller's intent about the duration of non-swappability that > distinguishes which of the two you call. If it's "just for a second > or three" dontswap is fine; if it's for hours, or more usually > (until the address space terminates, which might be months), you > want transwap because of the preferred storage consequence. > > - Historically, the latency costs were drastically different. The > differences narrowed, when states like "logically swapped" were > added. Transwap then was overkill for cases that dontswap could > handle. > > - Similarly, the consequences (how long might it take to vary a > storage element offline?) vary drastically. Waiting for an I/O > or 3 to complete (the intended dontswap case) might be tolerable, > waiting until some PC target address space (typically a long-running > server) terminates ... what could happen if it used dontswap > instead of transwap and it page-fixes non-preferred frames in the > element you want offline... was "frowned upon". > > - As others have noted, being non-swappable is NOT equivalent to > page-fixing frames. Work units running in non-swappable > address space(s) and referencing pageable storage CAN take page > faults (unless they're in state that does not permit them to be > suspended, in which case they're ABENDed). > > John Arwe > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
