Messages in this thread | | | Date | Tue, 13 Sep 2011 16:40:04 +0900 | From | Tejun Heo <> | Subject | Re: What is the difference between percpu_xxx and this_cpu_xxx? |
| |
On Tue, Sep 13, 2011 at 02:14:06PM +0800, Huang Ying wrote: > Hi, Eric, > > On 09/13/2011 02:11 PM, Eric Dumazet wrote: > > Le mardi 13 septembre 2011 à 12:28 +0800, Huang Ying a écrit : > >> Hi, > >> > >> If my understanding was correct, from the kernel source code, it appears > >> that percpu_xxx and this_cpu_xxx have the same semantics and > >> implementation in effect, haven’t them? > >> > >> If so, why do we need two API for the same thing? > > > > History mostly, and transition. > > > > percpu_inc() was an x86 only thing > > > > __get_cpu_var(var)++ -> percpu_inc(var) -> this_cpu_inc(var)
Also, we used to need separate accessors for static and dynamic percpu variables, so we have quite a few duplications in the interface.
> Thanks for clarification. Is there someone working on the transition? > Is that possible to translate most percpu_xxx to this_cpu_xxx blindly?
It's on my todo list but AFAIK nobody is actually working on it yet.
Thanks.
-- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |