On Mon, Aug 6, 2012 at 9:24 PM, Michal Hocko <mhocko@xxxxxxx> wrote:
> On Sat 04-08-12 14:08:31, Hillf Danton wrote:
>> The computation of page offset index is incorrect to be used in scanning
>> prio tree, as huge page offset is required, and is fixed with well
>> defined routine.
>>
>> Changes from v1
>> o s/linear_page_index/linear_hugepage_index/ for clearer code
>> o hp_idx variable added for less change
>>
>>
>> Signed-off-by: Hillf Danton <dhillf@xxxxxxxxx>
>> ---
>>
>> --- a/arch/x86/mm/hugetlbpage.c Fri Aug 3 20:34:58 2012
>> +++ b/arch/x86/mm/hugetlbpage.c Fri Aug 3 20:40:16 2012
>> @@ -62,6 +62,7 @@ static void huge_pmd_share(struct mm_str
>> {
>> struct vm_area_struct *vma = find_vma(mm, addr);
>> struct address_space *mapping = vma->vm_file->f_mapping;
>> + pgoff_t hp_idx;
>> pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) +
>> vma->vm_pgoff;
>
> So we have two indexes now. That is just plain ugly!
>
Two indexes result in less code change here and no change
in page_table_shareable. Plus linear_hugepage_index tells
clearly readers that hp_idx and idx are different.
Anyway I have no strong opinion to keep
page_table_shareable unchanged, but prefer less changes.
Thanks,
Hillf
>> struct prio_tree_iter iter;
>> @@ -72,8 +73,10 @@ static void huge_pmd_share(struct mm_str
>> if (!vma_shareable(vma, addr))
>> return;
>>
>> + hp_idx = linear_hugepage_index(vma, addr);
>> +
>> mutex_lock(&mapping->i_mmap_mutex);
>> - vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, idx, idx) {
>> + vma_prio_tree_foreach(svma, &iter, &mapping->i_mmap, hp_idx, hp_idx) {
>> if (svma == vma)
>> continue;
>>
>> --
>
> --
> Michal Hocko
> SUSE Labs
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