memblock: Introduce default allocation limit and use it to replace explicit ones
This introduce memblock.current_limit which is used to limit allocations
from memblock_alloc() or memblock_alloc_base(..., MEMBLOCK_ALLOC_ACCESSIBLE).
The old MEMBLOCK_ALLOC_ANYWHERE changes value from 0 to ~(u64)0 and can still
be used with memblock_alloc_base() to allocate really anywhere.
It is -no-longer- cropped to MEMBLOCK_REAL_LIMIT which disappears.
Note to archs: I'm leaving the default limit to MEMBLOCK_ALLOC_ANYWHERE. I
strongly recommend that you ensure that you set an appropriate limit
during boot in order to guarantee that an memblock_alloc() at any time
results in something that is accessible with a simple __va().
The reason is that a subsequent patch will introduce the ability for
the array to resize itself by reallocating itself. The MEMBLOCK core will
honor the current limit when performing those allocations.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index 0131684..770c5bf 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -115,6 +115,8 @@
memblock.reserved.regions[0].base = 0;
memblock.reserved.regions[0].size = 0;
memblock.reserved.cnt = 1;
+
+ memblock.current_limit = MEMBLOCK_ALLOC_ANYWHERE;
}
void __init memblock_analyze(void)
@@ -373,7 +375,7 @@
u64 __init memblock_alloc(u64 size, u64 align)
{
- return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
+ return memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ACCESSIBLE);
}
u64 __init memblock_alloc_base(u64 size, u64 align, u64 max_addr)
@@ -399,14 +401,9 @@
size = memblock_align_up(size, align);
- /* On some platforms, make sure we allocate lowmem */
- /* Note that MEMBLOCK_REAL_LIMIT may be MEMBLOCK_ALLOC_ANYWHERE */
- if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
- max_addr = MEMBLOCK_REAL_LIMIT;
-
/* Pump up max_addr */
- if (max_addr == MEMBLOCK_ALLOC_ANYWHERE)
- max_addr = ~(u64)0;
+ if (max_addr == MEMBLOCK_ALLOC_ACCESSIBLE)
+ max_addr = memblock.current_limit;
/* We do a top-down search, this tends to limit memory
* fragmentation by keeping early boot allocs near the
@@ -527,3 +524,9 @@
return memblock_overlaps_region(&memblock.reserved, base, size) >= 0;
}
+
+void __init memblock_set_current_limit(u64 limit)
+{
+ memblock.current_limit = limit;
+}
+