Re: [PATCH] mm: thp: register mm for khugepaged when merging vma for shmem

From: Yang Shi
Date: Thu Jun 21 2018 - 18:24:35 EST




On 6/21/18 3:10 PM, Kirill A. Shutemov wrote:
On Fri, Jun 22, 2018 at 05:40:47AM +0800, Yang Shi wrote:
When merging anonymous page vma, if the size of vam can fit in at least
s/vam/vma/

one hugepage, the mm will be registered for khugepaged for collapsing
THP in the future.

But, it skips shmem vma. Doing so for shmem too when merging vma in
order to increase the odd to collapse hugepage by khugepaged.
Good catch. Thanks.

I think the fix incomplete. We shouldn't require vma->anon_vma for shmem,
only for anonymous mappings. We don't support file-private THPs.

So you mean, shmem_file(vma->vm_file) && PageAnon(page)?


Also increase the count of shmem THP collapse. It looks missed before.
Separate patch, please.

Sure.

Thanks,
Yang