Commits
Heiko Carstens committed 4130b28f568
s390/ipl: revert Load Normal semantics for LPAR CCW-type re-IPL
This reverts the two commits
7afbeb6df2aa ("s390/ipl: always use load normal for CCW-type re-IPL")
0f7451ff3ab8 ("s390/ipl: use load normal for LPAR re-ipl")
The two commits did not take into account that behavior of standby
memory changes fundamentally if the re-IPL method is changed from
Load Clear to Load Normal.
In case of the old re-IPL clear method all memory that was initially
in standby state will be put into standby state again within the
re-IPL process. Or in other words: memory that was brought online
before a re-IPL will be offline again after a reboot.
Given that we use different re-IPL methods depending on the hypervisor
and CCW-type vs SCSI re-IPL it is not easy to tell in advance when and
why memory will stay online or will be offline after a re-IPL.
This does also have other side effects, since memory that is online
from the beginning will be in ZONE_NORMAL by default vs ZONE_MOVABLE
for memory that is offline.
Therefore, before the change, a user could online and offline memory
easily since standby memory was always in ZONE_NORMAL. After the
change, and a re-IPL, this depended on which memory parts were online
before the re-IPL.
From a usability point of view the current behavior is more than
suboptimal. Therefore revert these changes until we have a better
solution and get back to a consistent behavior. The bad thing about
this is that the time required for a re-IPL will be significantly
increased for configurations with several 100GB or 1TB of memory.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>