[PATCH] arm: Don't use memblock limit for the lowmem bound

From: Laura Abbott
Date: Mon May 11 2015 - 22:54:42 EST


From: Laura Abbott <labbott@xxxxxxxxxx>

The memblock limit is currently used in find_limits
to find the bounds for ZONE_NORMAL. The memblock
limit may need to be rounded down a PMD size to ensure
allocations are fully mapped though. This has the side
effect of reducing the amount of memory in ZONE_NORMAL.
Since we generally want to optimize for more lowmem, fix
this by using arm_lowmem_limit to calculate the bounds.
This what is used for actually mapping lowmem anyway.

Before:
# cat /proc/zoneinfo | grep managed
managed 62920

After:
# cat /proc/zoneinfo | grep managed
managed 63336



Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
arch/arm/mm/init.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index be92fa0..b4f9513 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -89,7 +89,7 @@ __tagtable(ATAG_INITRD2, parse_tag_initrd2);
static void __init find_limits(unsigned long *min, unsigned long *max_low,
unsigned long *max_high)
{
- *max_low = PFN_DOWN(memblock_get_current_limit());
+ *max_low = PFN_DOWN(arm_lowmem_limit);
*min = PFN_UP(memblock_start_of_DRAM());
*max_high = PFN_DOWN(memblock_end_of_DRAM());
}
--
2.1.0

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