| To: | "King, Steven R" <steven.r.king@xxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] get_page put_page cmpxchg problem? |
| From: | Keir Fraser <Keir.Fraser@xxxxxxxxxxxx> |
| Date: | 2005年7月21日 22:36:30 +0100 |
| Cc: | xen-devel@xxxxxxxxxxxxxxxxxxx |
| Delivery-date: | 2005年7月21日 21:30:49 +0000 |
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On 21 Jul 2005, at 21:59, King, Steven R wrote:
In put_page() we can be sure the refcnt is non-zero and so the domain ptr will not change under our feet. Therefore there's no need to include it in the cmpxchg when we update the reference count.Hi Folks,In -unstable (I haven't updated in a few days), I'm investigating a problem in which revalidate_l1() fails because get_page() fails due to a count_info of 0. While that problem is still hanging over me, I did notice that get_page() in include/asm-x86/mm.h does a 64-bit cmpxchg while put_page() only does a 32-bit cmpxchg. Seemed odd to me and possibly related to my bug. I'm running on a 32-bit machine without shadow tables.Can anyone offer an explanation?
-- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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