Re: [BUG REPORT] [mm-hotplug, aio] aio ring_pages can't be offlined

[Lin Feng]

Hi Zach,

Thanks for your advice. So agree, I will look into it to lead aio 
to use non-movable pages.


Thanks,
linfeng
On 11/30/2012 08:04 AM, Zach Brown wrote:
>> The best I can think of is to make changes in or around
>> get_user_pages(), to steal the pages from userspace and replace them
>> with non-movable ones before pinning them.  The performance cost of
>> something like this would surely be unacceptable for direct-io, but
>> maybe OK for the aio ring and futexes.
> 
> In the aio case it seems like it could be taught to populate the mapping
> with non-movable pages to begin with.  It's calling get_user_pages() a
> few lines after instantiating the mapping itself with do_mmap_pgoff().
> 
> - z
> 

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