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From: Robert Watson <rwatson@FreeBSD.org>
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Cc: freebsd-hackers@freebsd.org, Alan Cox <alc@cs.rice.edu>,
	Wojciech Puchar <wojtek@wojtek.tensor.gdynia.pl>
Subject: Re: large pages (amd64)
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On Tue, 30 Jun 2009, Mel Flynn wrote:

>>> It looks like sys/kern/kern_proc.c could call mincore around the loop at 
>>> line 1601 (rev 194498), but I know nothing about the vm subsystem to know 
>>> the implications or locking involved. There's still 16 bytes of spare to 
>>> consume, in the kve_vminfo struct though ;)
>>
>> Yes, to start with, you could replace the call to pmap_extract() with a 
>> call to pmap_mincore() and export a Boolean to user space that says, "This 
>> region of the address space contains one or more superpage mappings."
>
> How about attached?

I like the idea -- there are some style nits that need fixing though. 
Assuming Alan is happy with the VM side of things, I can do the cleanup and 
get it in the tree.

Robert N M Watson
Computer Laboratory
University of Cambridge

>
> % sudo procstat -av|grep 'S '
>  PID      START        END PRT  RES PRES REF SHD  FL TP PATH
> 1754 0x28900000 0x2ae00000 rw- 9385    0   3   0 --S df
> 2141 0x2f900000 0x30800000 rw- 3719    0   1   0 --S df
> 2146 0x3eec0000 0x4fac0000 rwx 1745    0   1   0 --S df
>
> -- 
> Mel
>
>