s390/mm: let vmalloc area size depend on physical memory size

To make sure that the vmalloc area size is for almost all cases large
enough let it depend on the (potential) physical memory size. There is
still the possibility to override this with the vmalloc kernel command
line parameter.

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index cc96b04cc0ba..95d13a252ed9 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -126,6 +126,21 @@ static void clear_bss_section(void)
 	memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
 }
 
+/*
+ * Set vmalloc area size to an 8th of (potential) physical memory
+ * size, unless size has been set by kernel command line parameter.
+ */
+static void setup_vmalloc_size(void)
+{
+	unsigned long size;
+
+	if (vmalloc_size_set)
+		return;
+	size = (memory_end ?: max_physmem_end) >> 3;
+	size = round_up(size, _SEGMENT_SIZE);
+	vmalloc_size = max(size, vmalloc_size);
+}
+
 void startup_kernel(void)
 {
 	unsigned long random_lma;
@@ -142,6 +157,7 @@ void startup_kernel(void)
 	parse_boot_command_line();
 	setup_memory_end();
 	detect_memory();
+	setup_vmalloc_size();
 
 	random_lma = __kaslr_offset = 0;
 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {