memblock: free allocated memblock_reserved_regions later
memblock_free_reserved_regions() calls memblock_free(), but
memblock_free() would double reserved.regions too, so we could free the
old range for reserved.regions.
Also tj said there is another bug which could be related to this.
| I don't think we're saving any noticeable
| amount by doing this "free - give it to page allocator - reserve
| again" dancing. We should just allocate regions aligned to page
| boundaries and free them later when memblock is no longer in use.
in that case, when DEBUG_PAGEALLOC, will get panic:
memblock_free: [0x0000102febc080-0x0000102febf080] memblock_free_reserved_regions+0x37/0x39
BUG: unable to handle kernel paging request at ffff88102febd948
IP: [<ffffffff836a5774>] __next_free_mem_range+0x9b/0x155
PGD 4826063 PUD cf67a067 PMD cf7fa067 PTE 800000102febd160
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
CPU 0
Pid: 0, comm: swapper Not tainted 3.5.0-rc2-next-20120614-sasha #447
RIP: 0010:[<ffffffff836a5774>] [<ffffffff836a5774>] __next_free_mem_range+0x9b/0x155
See the discussion at https://lkml.org/lkml/2012/6/13/469
So try to allocate with PAGE_SIZE alignment and free it later.
Reported-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memblock.c b/mm/memblock.c
index d438209..5cc6731 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -143,30 +143,6 @@
MAX_NUMNODES);
}
-/*
- * Free memblock.reserved.regions
- */
-int __init_memblock memblock_free_reserved_regions(void)
-{
- if (memblock.reserved.regions == memblock_reserved_init_regions)
- return 0;
-
- return memblock_free(__pa(memblock.reserved.regions),
- sizeof(struct memblock_region) * memblock.reserved.max);
-}
-
-/*
- * Reserve memblock.reserved.regions
- */
-int __init_memblock memblock_reserve_reserved_regions(void)
-{
- if (memblock.reserved.regions == memblock_reserved_init_regions)
- return 0;
-
- return memblock_reserve(__pa(memblock.reserved.regions),
- sizeof(struct memblock_region) * memblock.reserved.max);
-}
-
static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
{
type->total_size -= type->regions[r].size;
@@ -184,6 +160,18 @@
}
}
+phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info(
+ phys_addr_t *addr)
+{
+ if (memblock.reserved.regions == memblock_reserved_init_regions)
+ return 0;
+
+ *addr = __pa(memblock.reserved.regions);
+
+ return PAGE_ALIGN(sizeof(struct memblock_region) *
+ memblock.reserved.max);
+}
+
/**
* memblock_double_array - double the size of the memblock regions array
* @type: memblock type of the regions array being doubled
@@ -204,6 +192,7 @@
phys_addr_t new_area_size)
{
struct memblock_region *new_array, *old_array;
+ phys_addr_t old_alloc_size, new_alloc_size;
phys_addr_t old_size, new_size, addr;
int use_slab = slab_is_available();
int *in_slab;
@@ -217,6 +206,12 @@
/* Calculate new doubled size */
old_size = type->max * sizeof(struct memblock_region);
new_size = old_size << 1;
+ /*
+ * We need to allocated new one align to PAGE_SIZE,
+ * so we can free them completely later.
+ */
+ old_alloc_size = PAGE_ALIGN(old_size);
+ new_alloc_size = PAGE_ALIGN(new_size);
/* Retrieve the slab flag */
if (type == &memblock.memory)
@@ -245,11 +240,11 @@
addr = memblock_find_in_range(new_area_start + new_area_size,
memblock.current_limit,
- new_size, sizeof(phys_addr_t));
+ new_alloc_size, PAGE_SIZE);
if (!addr && new_area_size)
addr = memblock_find_in_range(0,
min(new_area_start, memblock.current_limit),
- new_size, sizeof(phys_addr_t));
+ new_alloc_size, PAGE_SIZE);
new_array = addr ? __va(addr) : 0;
}
@@ -279,13 +274,13 @@
kfree(old_array);
else if (old_array != memblock_memory_init_regions &&
old_array != memblock_reserved_init_regions)
- memblock_free(__pa(old_array), old_size);
+ memblock_free(__pa(old_array), old_alloc_size);
/* Reserve the new array if that comes from the memblock.
* Otherwise, we needn't do it
*/
if (!use_slab)
- BUG_ON(memblock_reserve(addr, new_size));
+ BUG_ON(memblock_reserve(addr, new_alloc_size));
/* Update slab flag */
*in_slab = use_slab;