Roy.Lyseng at Sun.COM
Tue Oct 9 13:47:57 UTC 2007
Todd Lipcon wrote:
> On Tue, 9 Oct 2007, Roy Lyseng wrote:
>>> Are increments atomic across SMP/multicore? It'd be hard to corrupt
>>> it, but I don't know off the top of my head if it's safe to ignore
>>> locking when you're just reading/writing to one set of 4-8bytes. I'll
>>> have to read up (or hope someone who knows better about this use of
>>> memory barriers chimes in. It's not something I deal with much
>>> outside of tracking down kernel bugs on SMP systems).
>> Increments are generally not atomic. You have interfaces like
>> atomic_inc_ulong() in Solaris 10 and in the Linux kernel (AFAIK).
> In Linux there's /usr/include/asm/atomic.h which has:
> void atomic_inc(atomic_t *v)
> Not sure if it's supported on every last platform, though.
My Linux box (RHEL based on 2.6.9) says that this is for the kernel only.
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