diff options
author | Yinghai Lu <yinghai@kernel.org> | 2012-07-11 14:02:56 -0700 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-07-16 09:04:45 -0700 |
commit | 7ad71f960f0f6e06cbded278809674afc515036a (patch) | |
tree | df62cd2fb579dc1ded7ec28c669ed03bf506ffe9 /mm | |
parent | 0fa627b15c842095b5147f381fa1943a6a46bb01 (diff) | |
download | lwn-7ad71f960f0f6e06cbded278809674afc515036a.tar.gz lwn-7ad71f960f0f6e06cbded278809674afc515036a.zip |
memblock: free allocated memblock_reserved_regions later
commit 29f6738609e40227dabcc63bfb3b84b3726a75bd upstream.
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/memblock.c | 51 | ||||
-rw-r--r-- | mm/nobootmem.c | 38 |
2 files changed, 46 insertions, 43 deletions
diff --git a/mm/memblock.c b/mm/memblock.c index 0e737d9ab2ba..280d3d7835d6 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -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; diff --git a/mm/nobootmem.c b/mm/nobootmem.c index 1983fb1c7026..218e6f95d44f 100644 --- a/mm/nobootmem.c +++ b/mm/nobootmem.c @@ -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) { - 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; - } - } + for_each_free_mem_range(i, MAX_NUMNODES, &start, &end, NULL) + count += __free_memory_core(start, end); + + /* 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; } |