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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>
This commit is contained in:
Yinghai Lu 2012-07-11 14:02:56 -07:00 committed by Linus Torvalds
parent 99ab7b1944
commit 29f6738609
3 changed files with 46 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/memblock.h
View File

@ -50,9 +50,7 @@ phys_addr_t memblock_find_in_range_node(phys_addr_t start, phys_addr_t end,
phys_addr_t size, phys_addr_t align, int nid);
phys_addr_t memblock_find_in_range(phys_addr_t start, phys_addr_t end,
phys_addr_t size, phys_addr_t align);
int memblock_free_reserved_regions(void);
int memblock_reserve_reserved_regions(void);
phys_addr_t get_allocated_memblock_reserved_regions_info(phys_addr_t *addr);
void memblock_allow_resize(void);
int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid);
int memblock_add(phys_addr_t base, phys_addr_t size);

51
mm/memblock.c
View File

@ -143,30 +143,6 @@ phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
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 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
}
}
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 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
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 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
/* 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 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
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 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
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;

36
mm/nobootmem.c
View File

@ -105,27 +105,35 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
__free_pages_bootmem(pfn_to_page(i), 0);
}
static unsigned long __init __free_memory_core(phys_addr_t start,
phys_addr_t end)
{
unsigned long start_pfn = PFN_UP(start);
unsigned long end_pfn = min_t(unsigned long,
PFN_DOWN(end), max_low_pfn);
if (start_pfn > end_pfn)
return 0;
__free_pages_memory(start_pfn, end_pfn);
return end_pfn - start_pfn;
}
unsigned long __init free_low_memory_core_early(int nodeid)
{
unsigned long count = 0;
phys_addr_t start, end;
phys_addr_t start, end, size;
u64 i;
/* free reserved array temporarily so that it's treated as free area */
memblock_free_reserved_regions();
for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL)
count += __free_memory_core(start, end);
for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL) {
unsigned long start_pfn = PFN_UP(start);
unsigned long end_pfn = min_t(unsigned long,
PFN_DOWN(end), max_low_pfn);
if (start_pfn < end_pfn) {
__free_pages_memory(start_pfn, end_pfn);
count += end_pfn - start_pfn;
}
}
/* free range that is used for reserved array if we allocate it */
size = get_allocated_memblock_reserved_regions_info(&start);
if (size)
count += __free_memory_core(start, start + size);
/* put region array back? */
memblock_reserve_reserved_regions();
return count;
}