Messages in this thread | | | Date | Thu, 30 Apr 2009 09:16:31 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH] Fix dirty page accounting in redirty_page_for_writepage() |
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On Thu, 30 Apr 2009, Ingo Molnar wrote: > > c0436275: 64 83 05 20 5f 6a c0 addl $0x1,%fs:0xc06a5f20 > > There's no atomic instructions at all - the counters here are only > accessed locally. They are local-irq-atomic, but not > cacheline-atomic.
On other architectures, you need the whole "disable preemption, load-locked, store-conditional, test-and-loop, enable preemption" thing.
Or "disable interrupts, load, store, restore interrupts".
There really aren't very many architectures that can do almost unrestricted ALU ops in a single instruction (and thus automatically safe from preemption and interrupts).
Linus
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