memblock: Add arch function to control coalescing of memblock memory regions
Some archs such as ARM want to avoid coalescing accross things such
as the lowmem/highmem boundary or similar. This provides the option
to control it via an arch callback for which a weak default is provided
which always allows coalescing.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index 0787790..8715f09 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -241,6 +241,12 @@
return 0;
}
+extern int __weak memblock_memory_can_coalesce(phys_addr_t addr1, phys_addr_t size1,
+ phys_addr_t addr2, phys_addr_t size2)
+{
+ return 1;
+}
+
static long memblock_add_region(struct memblock_type *type, phys_addr_t base, phys_addr_t size)
{
unsigned long coalesced = 0;
@@ -262,6 +268,10 @@
return 0;
adjacent = memblock_addrs_adjacent(base, size, rgnbase, rgnsize);
+ /* Check if arch allows coalescing */
+ if (adjacent != 0 && type == &memblock.memory &&
+ !memblock_memory_can_coalesce(base, size, rgnbase, rgnsize))
+ break;
if (adjacent > 0) {
type->regions[i].base -= size;
type->regions[i].size += size;
@@ -274,7 +284,14 @@
}
}
- if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1)) {
+ /* If we plugged a hole, we may want to also coalesce with the
+ * next region
+ */
+ if ((i < type->cnt - 1) && memblock_regions_adjacent(type, i, i+1) &&
+ ((type != &memblock.memory || memblock_memory_can_coalesce(type->regions[i].base,
+ type->regions[i].size,
+ type->regions[i+1].base,
+ type->regions[i+1].size)))) {
memblock_coalesce_regions(type, i, i+1);
coalesced++;
}