Messages in this thread | | | Date | Fri, 8 Feb 2002 13:36:27 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [RFC] New locking primitive for 2.5 |
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On Fri, 8 Feb 2002, Ingo Molnar wrote: > > and regarding the reintroduction of BKL, *please* do not just use a global > locks around such pieces of code, lock bouncing sucks on SMP, even if > there is no overhead.
I'd suggest not having a lock at all, but instead add two functions: one to read a 64-bit value atomically, the other to write it atomically (and they'd be atomic only wrt each other, no memory barriers etc implied).
On 64-bit architectures that's just a direct dereference, and even on x86 it's just a "cmpxchg8b".
Linus
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