Messages in this thread | | | Date | Fri, 14 Jan 2005 13:02:28 +0100 (CET) | From | Roman Zippel <> | Subject | Re: page table lock patch V15 [0/7]: overview |
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Hi,
On Fri, 14 Jan 2005, Andi Kleen wrote:
> > But there might be a loss in the UP case. Spinlocks are optimized away, > > but your cmpxchg emulation enables/disables interrupts with every access. > > Only for 386s and STI/CLI is quite cheap there.
But it's still not free and what about other archs? Why not just check __HAVE_ARCH_CMPXCHG and provide a replacement, which is guaranteed cheaper if no interrupt synchronisation is needed.
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