Messages in this thread |  | | Date | Tue, 2 Jan 2001 12:59:24 +0100 | From | Andi Kleen <> | Subject | Re: [PATCH] move xchg/cmpxchg to atomic.h |
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On Tue, Jan 02, 2001 at 11:22:42AM +0000, Matthew Wilcox wrote: > On Tue, Jan 02, 2001 at 01:03:48AM -0800, David S. Miller wrote: > > If you require an external agent (f.e. your spinlock) because you > > cannot implement xchg with a real atomic sequence, this breaks the > > above assumptions. > > We really can't. We _only_ have load-and-zero. And it has to be 16-byte > aligned. xchg() is just not something the CPU implements.
The network code relies on the reader-xchg semantics David described in several places.
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