Re: [PATCHv3 15/41] filemap: handle huge pages in do_generic_file_read()

From	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCHv3 15/41] filemap: handle huge pages in do_generic_file_read()
Date	2016-11-07 17:10 +0100
Message-ID	<sAUEF-5ny-25@gated-at.bofh.it> (permalink)
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On Mon, Nov 07, 2016 at 07:01:03AM -0800, Christoph Hellwig wrote:
> On Mon, Nov 07, 2016 at 02:13:05PM +0300, Kirill A. Shutemov wrote:
> > It looks like a huge limitation to me.
> 
> The DAX PMD fault code can live just fine with it.

There's no way out for DAX as we map backing storage directly into
userspace. There's no such limitation for page-cache. And I don't see a
point to introduce such limitation artificially.

Backing storage fragmentation can be a weight on decision whether we want
to allocate huge page, but it shouldn't be show-stopper.

> And without it performance would suck anyway.

It depends on workload, obviously.

-- 
 Kirill A. Shutemov

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Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-10-31 19:20 +0100
  Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Jan Kara <jack@suse.cz> - 2016-11-01 17:50 +0100
    Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-11-02 09:40 +0100
      Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Christoph Hellwig <hch@infradead.org> - 2016-11-02 15:40 +0100
      Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Jan Kara <jack@suse.cz> - 2016-11-03 22:00 +0100
        Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-11-07 12:40 +0100
          Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Christoph Hellwig <hch@infradead.org> - 2016-11-07 16:00 +0100
    Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Christoph Hellwig <hch@infradead.org> - 2016-11-02 15:40 +0100
      Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Jan Kara <jack@suse.cz> - 2016-11-03 19:00 +0100
      Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-11-07 12:40 +0100
        Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() Christoph Hellwig <hch@infradead.org> - 2016-11-07 16:30 +0100
          Re: [PATCHv3 15/41] filemap: handle huge pages in  do_generic_file_read() "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-11-07 17:10 +0100

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