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* mini-os: sbrk() doesn't allocate pages?
@ 2008-08-14  8:04 Gerd Hoffmann
  2008-08-14  8:42 ` Gerd Hoffmann
  2008-08-14  9:43 ` Samuel Thibault
  0 siblings, 2 replies; 3+ messages in thread
From: Gerd Hoffmann @ 2008-08-14  8:04 UTC (permalink / raw)
  To: Xen Development Mailing List

  Hi,

I'm wondering how the mini-os heap allocater work.  The sbrk() function
in mm.c seems to *not* allocate pages for the heap.  Instead it uses the
zero page and maps it into the heap space when a new page is needed ...

I can't believe is is supposed to work that way.  Is that a bug?  Did I
miss some logic somewhere in the code?

wondering,
  Gerd

-- 
http://kraxel.fedorapeople.org/xenner/

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: mini-os: sbrk() doesn't allocate pages?
  2008-08-14  8:04 mini-os: sbrk() doesn't allocate pages? Gerd Hoffmann
@ 2008-08-14  8:42 ` Gerd Hoffmann
  2008-08-14  9:43 ` Samuel Thibault
  1 sibling, 0 replies; 3+ messages in thread
From: Gerd Hoffmann @ 2008-08-14  8:42 UTC (permalink / raw)
  To: Xen Development Mailing List

Gerd Hoffmann wrote:
>   Hi,
> 
> I'm wondering how the mini-os heap allocater work.  The sbrk() function
> in mm.c seems to *not* allocate pages for the heap.  Instead it uses the
> zero page and maps it into the heap space when a new page is needed ...
> 
> I can't believe is is supposed to work that way.  Is that a bug?  Did I
> miss some logic somewhere in the code?

Oh, cow in the pagefault handler, that is the missing bit ...

cheers,
  Gerd


-- 
http://kraxel.fedorapeople.org/xenner/

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: mini-os: sbrk() doesn't allocate pages?
  2008-08-14  8:04 mini-os: sbrk() doesn't allocate pages? Gerd Hoffmann
  2008-08-14  8:42 ` Gerd Hoffmann
@ 2008-08-14  9:43 ` Samuel Thibault
  1 sibling, 0 replies; 3+ messages in thread
From: Samuel Thibault @ 2008-08-14  9:43 UTC (permalink / raw)
  To: Gerd Hoffmann; +Cc: Xen Development Mailing List

Gerd Hoffmann, le Thu 14 Aug 2008 10:04:31 +0200, a écrit :
> I can't believe is is supposed to work that way.

That's how it usually works in unix environments :)

Samuel

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2008-08-14  9:43 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2008-08-14  8:04 mini-os: sbrk() doesn't allocate pages? Gerd Hoffmann
2008-08-14  8:42 ` Gerd Hoffmann
2008-08-14  9:43 ` Samuel Thibault

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