Messages in this thread | | | Subject | Re: ordered memory access | From | Jes Sorensen <> | Date | 30 Sep 1999 14:47:09 +0200 |
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>>>>> "Benjamin" == Benjamin Herrenschmidt <bh40@calva.net> writes:
Benjamin> On Thu, Sep 30, 1999, Jes Sorensen <Jes.Sorensen@cern.ch> Benjamin> wrote: >> atomic_foo() should be ordered, at least that the idea behind it as >> far as I understand. >> >> Otherwise you want to look at mb(), rmb() and wmb(). mb() is a >> generic memory barrier, wmb() makes sure a write is issues before >> another write() and rmb() ... you get the idea ;-)
Benjamin> The last time I discussed this with Paul Mackerras, he told Benjamin> me that the atomic_xxx functions were not expected to Benjamin> enforce ordering. (At this time, the linuxppc versions Benjamin> didn't do a sync instruction for this reason). I didn't Benjamin> check recent linuxppc versions however.
Well it seems like another case where we are not exactly sure what the functions are supposed to do (eg. like with readl/writel). Thats why I suggest it is being documented at least.
Jes
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