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Re: Synchronizing auxiliary mutex data
On Jun 20 2017, Torvald Riegel <triegel@redhat.com> wrote:
> On Tue, 2017-06-20 at 15:40 +0200, Andreas Schwab wrote:
>> On Jun 20 2017, Torvald Riegel <triegel@redhat.com> wrote:
>>
>> > I described exactly that above. It is guaranteed for the code above by
>> > the memory model. Implementations of the memory model (so in our case,
>> > the compiler and the HW) have to ensure that. For example, in the x86
>> > memory model, acquire and release MO are implicit, so because the
>> > compiler is not allowed to reorder in this case, the HW ensures that
>> > lock()'s write to owner happens after unlock's write to owner.
>>
>> What about the read in the locking thread?
>
> I have answered that in my previous emails.
What does prevent the cpu from loading it from its cache?
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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