Re: Early boot panic on machine with lots of memory
From: Tejun Heo <tj@kernel.org>
Date: 2012-06-21 20:17:33
Also in:
lkml
Hello, Yinghai. On Tue, Jun 19, 2012 at 07:57:45PM -0700, Yinghai Lu wrote:
quoted hunk ↗ jump to hunk
if it is that case, that change could fix other problem problem too.--- during the one free reserved.regions could double the array.
Yeah, that sounds much more attractive to me too. Some comments on the patch tho.
quoted hunk ↗ jump to hunk
/** * memblock_double_array - double the size of the memblock regions array * @type: memblock type of the regions array being doubled@@ -216,7 +204,7 @@ static int __init_memblock memblock_doub /* Calculate new doubled size */ old_size = type->max * sizeof(struct memblock_region); - new_size = old_size << 1; + new_size = PAGE_ALIGN(old_size << 1);
We definintely can use some comments explaining why we want page
alignment. It's kinda subtle.
This is a bit confusing here because old_size is the proper size
without padding while new_size is page aligned size with possible
padding. Maybe discerning {old|new}_alloc_size is clearer? Also, I
think adding @new_cnt variable which is calculated together would make
the code easier to follow. So, sth like,
/* explain why page aligning is necessary */
old_size = type->max * sizeof(struct memblock_region);
old_alloc_size = PAGE_ALIGN(old_size);
new_max = type->max << 1;
new_size = new_max * sizeof(struct memblock_region);
new_alloc_size = PAGE_ALIGN(new_size);
and use alloc_sizes for alloc/frees and sizes for everything else.
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);I'm afraid this is too early. We don't want the region to be unmapped yet. This should only happen after all memblock usages are finished which I don't think is the case yet. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>