On Wed 13-06-12 15:57:23, Aneesh Kumar K.V wrote:
> From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
>
> Use a mmu_gather instead of a temporary linked list for accumulating
> pages when we unmap a hugepage range
Sorry for coming up with the comment that late but you owe us an
explanation _why_ you are doing this.
I assume that this fixes a real problem when we take i_mmap_mutex
already up in
unmap_mapping_range
mutex_lock(&mapping->i_mmap_mutex);
unmap_mapping_range_tree | unmap_mapping_range_list
unmap_mapping_range_vma
zap_page_range_single
unmap_single_vma
unmap_hugepage_range
mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
And that this should have been marked for stable as well (I haven't
checked when this has been introduced).
But then I do not see how this help when you still do this:
[...]
> diff --git a/mm/memory.c b/mm/memory.c
> index 1b7dc66..545e18a 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -1326,8 +1326,11 @@ static void unmap_single_vma(struct mmu_gather *tlb,
> * Since no pte has actually been setup, it is
> * safe to do nothing in this case.
> */
> - if (vma->vm_file)
> - unmap_hugepage_range(vma, start, end, NULL);
> + if (vma->vm_file) {
> + mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
> + __unmap_hugepage_range(tlb, vma, start, end, NULL);
> + mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
> + }
> } else
> unmap_page_range(tlb, vma, start, end, details);
> }
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>