linux_dsm_epyc7002/arch/s390
Heiko Carstens ead1dec8ed 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>
2017-06-12 16:26:01 +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/crypto: fix aes/paes Kconfig dependeny 2017-06-12 16:25:58 +02:00
hypfs s390: hypfs: make inode explicitly non-modular 2016-10-31 17:55:40 +01:00
include s390: provide default ioremap and iounmap declaration 2017-06-12 16:26:00 +02:00
kernel s390/ipl: revert Load Normal semantics for LPAR CCW-type re-IPL 2017-06-12 16:26:01 +02:00
kvm Merge branch 'akpm' (patches from Andrew) 2017-05-08 18:17:56 -07:00
lib s390/uaccess: use sane length for __strncpy_from_user() 2017-05-09 10:43:24 +02:00
mm s390/fault: use _ASCE_ORIGIN instead of PAGE_MASK 2017-06-12 16:25:59 +02:00
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/facilities: remove stfle requirement 2017-06-12 16:25:59 +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 s390/mm: implement 5 level pages tables 2017-06-12 16:25:54 +02:00
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