s390/kdump: Do not add standby memory for kdump

Standby memory that is located outside [0,OLDMEM_SIZE] is currently used
by the s390 memory detection. This leads to additional memory consumption
due to allocation of page structures. To fix this, we now do not
add standby memory if the kernel is started in kdump mode.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/s390/char/sclp_cmd.c b/drivers/s390/char/sclp_cmd.c
index 30a2255389e5..cd798386b622 100644
--- a/drivers/s390/char/sclp_cmd.c
+++ b/drivers/s390/char/sclp_cmd.c
@@ -627,6 +627,8 @@ static int __init sclp_detect_standby_memory(void)
         struct read_storage_sccb *sccb;
         int i, id, assigned, rc;
 
+        if (OLDMEM_BASE) /* No standby memory in kdump mode */
+                return 0;
         if (!early_read_info_sccb_valid)
                 return 0;
         if ((sclp_facilities & 0xe00000000000ULL) != 0xe00000000000ULL)