openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
This commit is contained in:
Heiko Carstens 2017-06-06 13:55:42 +02:00 committed by Martin Schwidefsky
parent 2b7b9817c2
commit ead1dec8ed
1 changed files with 1 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/s390/kernel/ipl.c
View File

@ -564,8 +564,6 @@ static struct kset *ipl_kset;
static void __ipl_run(void *unused)
{
if (MACHINE_IS_LPAR && ipl_info.type == IPL_TYPE_CCW)
diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
diag308(DIAG308_LOAD_CLEAR, NULL);
if (MACHINE_IS_VM)
__cpcmd("IPL", NULL, 0, NULL);
@ -1088,9 +1086,6 @@ static void __reipl_run(void *unused)
break;
case REIPL_METHOD_CCW_DIAG:
diag308(DIAG308_SET, reipl_block_ccw);
if (MACHINE_IS_LPAR)
diag308(DIAG308_LOAD_NORMAL_DUMP, NULL);
else
diag308(DIAG308_LOAD_CLEAR, NULL);
break;
case REIPL_METHOD_FCP_RW_DIAG: