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

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Date:   Fri, 22 Jun 2018 01:10:08 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Yang Shi <yang.shi@...ux.alibaba.com>
Cc:     hughd@...gle.com, kirill.shutemov@...ux.intel.com, vbabka@...e.cz,
        akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: thp: register mm for khugepaged when merging vma for
 shmem

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.

> Also increase the count of shmem THP collapse. It looks missed before.

Separate patch, please.

-- 
 Kirill A. Shutemov