Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap()

From	Dan Williams <dan.j.williams@intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap()
Date	2017-09-27 18:00 +0200
Message-ID	<uumUG-557-21@gated-at.bofh.it> (permalink)
References	(4 earlier) <uu3Im-pY-17@gated-at.bofh.it> <uu5h8-1ye-15@gated-at.bofh.it> <uu5TP-1KX-13@gated-at.bofh.it> <uuiR4-1LQ-17@gated-at.bofh.it> <uumBk-4YL-19@gated-at.bofh.it>
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On Wed, Sep 27, 2017 at 8:39 AM, Ross Zwisler
<ross.zwisler@linux.intel.com> wrote:
> On Wed, Sep 27, 2017 at 01:35:27PM +0200, Jan Kara wrote:
[..]
>> Hum, this is an interesting option. So do you suggest that filesystems
>> supporting DAX would always setup mappings with VM_MIXEDMAP and without
>> VM_HUGEPAGE and thus we'd get rid of dependency on S_DAX flag in ->mmap?
>> That could actually work. The only possible issue I can see is that
>> VM_MIXEDMAP is still slightly different from normal page mappings and it
>> could have some performance implications - e.g. copy_page_range() does more
>> work on VM_MIXEDMAP mappings but not on normal page mappings.
>
> It looks like having VM_MIXEDMAP always set for filesystems that support DAX
> might affect their memory's NUMA migration in the non-DAX case?
>
> 8e76d4e sched, numa: do not hint for NUMA balancing on VM_MIXEDMAP mappings

Addressed separately here:

c1ef8e2c0235 mm: disable numa migration faults for dax vmas

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Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-09-26 21:00 +0200
  Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Dan Williams <dan.j.williams@intel.com> - 2017-09-26 21:30 +0200
    Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-09-26 23:10 +0200
      Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Dan Williams <dan.j.williams@intel.com> - 2017-09-26 23:50 +0200
        Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Jan Kara <jack@suse.cz> - 2017-09-27 13:40 +0200
          Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Dan Williams <dan.j.williams@intel.com> - 2017-09-27 16:10 +0200
            Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Jan Kara <jack@suse.cz> - 2017-09-27 17:10 +0200
              Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Dan Williams <dan.j.williams@intel.com> - 2017-09-27 17:40 +0200
          Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Ross Zwisler <ross.zwisler@linux.intel.com> - 2017-09-27 17:40 +0200
            Re: [PATCH 6/7] mm, fs: introduce file_operations->post_mmap() Dan Williams <dan.j.williams@intel.com> - 2017-09-27 18:00 +0200

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