Messages in this thread | | | Date | Mon, 12 Dec 2011 18:10:31 +0800 | Subject | Re: [PATCH 3/3] kref: Remove the memory barriers | From | Ming Lei <> |
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On Mon, Dec 12, 2011 at 4:56 PM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, 2011-12-12 at 11:48 +0800, Ming Lei wrote: >> > LOCK >> > obj = lookup(); /* lets assume obj != NULL */ >> > kref_get(&obj->ref); >> > UNLOCK >> > >> > value = obj->member; >> > >> > kref_put(&obj->ref); >> > >> > Now, under our memory model, the read from obj->member can both happen, >> > or be observed to happen before the increment from kref_get() is >> > processed. >> >> It should be the problem if another CPU observed that write/read obj >> is done before kref_get. > > WHY?!?!?!
I did't say the reason because it is same with the example I explained in the same reply. So if you can make me enlightened on this example, all will be OK, :-)
thanks, -- Ming Lei -- 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/
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