linux/arch/s390
Heiko Carstens 4130b28f56 s390/ipl: revert Load Normal semantics for LPAR CCW-type re-IPL
This reverts the two commits

7afbeb6df2 ("s390/ipl: always use load normal for CCW-type re-IPL")
0f7451ff3a ("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>
2017-06-14 15:35:31 +02:00
..
appldata sched/headers: Move task statistics APIs from <linux/sched.h> to <linux/sched/stat.h> 2017-03-03 01:43:43 +01:00
boot s390/decompressor: fix initrd corruption caused by bss clear 2017-03-22 08:21:20 +01:00
configs s390: update defconfig 2017-06-08 15:53:48 +02:00
crypto s390/crypt: use the correct module alias for paes_s390. 2017-04-26 16:52:57 +02:00
hypfs s390: hypfs: make inode explicitly non-modular 2016-10-31 17:55:40 +01:00
include KVM: s390: Fix for master (4.12) 2017-06-08 16:35:18 +02:00
kernel s390/ipl: revert Load Normal semantics for LPAR CCW-type re-IPL 2017-06-14 15:35:31 +02:00
kvm KVM: s390: fix ais handling vs cpu model 2017-05-31 19:54:49 +02:00
lib s390/uaccess: use sane length for __strncpy_from_user() 2017-05-09 10:43:24 +02:00
mm s390: use set_memory.h header 2017-05-08 17:15:13 -07:00
net s390: use set_memory.h header 2017-05-08 17:15:13 -07:00
numa s390/numa: pin all possible cpus to nodes early 2016-12-07 07:23:33 +01:00
oprofile s390/dumpstack: restore reliable indicator for call traces 2016-10-17 14:44:30 +02:00
pci s390/pci: remove forward declaration 2017-04-05 07:35:24 +02:00
tools s390: kvm: Cpu model support for msa6, msa7 and msa8 2017-04-26 14:19:01 +02:00
defconfig s390: update defconfig 2017-06-08 15:53:48 +02:00
Kbuild s390/crypto: Provide s390 specific arch random functionality. 2017-04-26 13:41:35 +02:00
Kconfig security/keys: add CONFIG_KEYS_COMPAT to Kconfig 2017-06-09 13:29:45 +10:00
Kconfig.debug Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2017-02-22 10:20:04 -08:00
Makefile s390: add assembler include path for vx-insn.h 2016-09-06 11:00:04 +02:00