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From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Armin Rigo <arigo@tunes.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Christoph Hellwig <hch@infradead.org>,
        Kenny Simpson <theonetruekenny@gmail.com>,
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Subject: Re: remap_file_pages() use
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Date: Mon, 19 May 2014 18:53:36 +0300 (EEST)
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Armin Rigo wrote:
> Hi Kirill,
> 
> On 19 May 2014 17:17, Kirill A. Shutemov
> <kirill.shutemov@linux.intel.com> wrote:
> > IIUC PyPy uses the syscall in some early prototype and looks like guys are
> > okay to rework it to mmap() if default sysctl_max_map_count will be high
> > enough.
> 
> Yes, we can switch easily if needed.  The syscall is not in any
> "production" version yet.
> 
> Please note that "high enough" in this context means higher than
> 2**20.  We need it high enough to handle regularly 10-20% of all the
> RAM used by each program.  If I count correctly, at 20%, 2**20 fails
> above 20GB.  In general I would suggest to use a default limit that
> depends on the amount of RAM (+swap) available.

Is it nessesary to remap in 4k chunks for you?
What about 64k chunks? Or something bigger?

This way you can scale down required number of VMAs to something more
reasonable.

-- 
 Kirill A. Shutemov