On Thu, Jun 21, 2012 at 1:17 PM, Tejun Heo <tj@xxxxxxxxxx> wrote:
> Hello, Yinghai.
>
> On Tue, Jun 19, 2012 at 07:57:45PM -0700, Yinghai Lu wrote:
>> 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.
>
>> /**
>> * 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.
yes.
>
> 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.
ok, will add new_alloc_size, old_alloc_size.
>
>> 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.
No, it is not early. at that time memblock usage is done.
Also I tested one system with huge memory, duplicated the problem on
KVM that Sasha met.
my patch fixes the problem.
please check attached patch.
Also I add another patch to double check if there is any reference
with reserved.region.
so far there is no reference found.
Thanks
Yinghai
Attachment:
fix_free_memblock_reserve_v4_5.patch
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Attachment:
memblock_reserved_clear_check.patch
Description: Binary data