linux-kernel - Re: [RFC v4 0/3] mm: zap pages with read mmap

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Message-ID: <f47b5a41-3fb1-ac81-1ead-78e4ac5fae51@linux.alibaba.com>
Date:   Thu, 12 Jul 2018 16:45:18 -0700
From:   Yang Shi <yang.shi@...ux.alibaba.com>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     "Kirill A. Shutemov" <kirill@...temov.name>, willy@...radead.org,
        ldufour@...ux.vnet.ibm.com, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC v4 0/3] mm: zap pages with read mmap_sem in munmap for large
 mapping



On 7/12/18 1:04 AM, Michal Hocko wrote:
> On Wed 11-07-18 10:04:48, Yang Shi wrote:
> [...]
>> One approach is to save all the vmas on a separate list, then zap_page_range
>> does unmap with this list.
> Just detached unmapped vma chain from mm. You can keep the existing
> vm_next chain and reuse it.

Yes. Other than this, we still need do:

   * Tell zap_page_range not update vm_flags as what I did in v4. Of 
course without VM_DEAD this time

   * Extract pagetable free code then do it after zap_page_range. I 
think I can just cal free_pgd_range() directly.

>