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xen-devel
RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks
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To: |
"Puthiyaparambil, Aravindh" <aravindh.puthiyaparambil@xxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx> |
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Subject: |
RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks |
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From: |
"Ian Pratt" <m+Ian.Pratt@xxxxxxxxxxxx> |
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Date: |
Wed, 5 Oct 2005 20:49:07 +0100 |
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Cc: |
"Koren, Bradley J" <Bradley.Koren@xxxxxxxxxx>, "Subrahmanian, Raj" <raj.subrahmanian@xxxxxxxxxx>, "Vessey, Bruce A" <Bruce.Vessey@xxxxxxxxxx> |
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Wed, 05 Oct 2005 19:46:35 +0000 |
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[Xen-devel] [PATCH] "lock cmpxch8b" and split locks |
> I have been looking at the following bug
> http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=252
> That investigation is still underway.
>
> While looking at this problem I found that in "lock cmpxch8b
> &page->count_info" occurring in "get_page( )",
> "&page->count_info" is on a misaligned address. Furthermore
> the address of "page" is not modulo 64. So the "lock
> cmpxch8b" can happen across cache lines and lead to a split
> lock. On systems which have multiple buses, the atomicity of
> such a statement is not assured and can cause synchronization
> problems.
>
> I have attached a patch which solves this issue.
We can't just increase the size of pfn_info structure -- it has
implications for the amount of VM space that Xen uses. This will require
more thought.
Ian
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- [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks,
Ian Pratt <=
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Nakajima, Jun
- RE: [Xen-devel] [PATCH] "lock cmpxch8b" and split locks, Puthiyaparambil, Aravindh
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