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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 10:21 +0200, Andreas Schwab wrote:
>> On Jun 19 2017, Torvald Riegel <triegel@redhat.com> wrote:
>>
>> > * We write to __owner only when in the critical section, with relaxed
>> > MO; we write TID after lock and 0 before unlock. Those writes are
>> > ordered by the critical section.
>>
>> How does it guarantee that the thread calling pthread_mutex_lock see the
>> change that the thread calling pthread_mutex_unlock did?
>
> I suppose you are referring to the writes? If so, because of the
> unlock/lock synchronization.
But the fields are independent of the lock field. How do the two cpus
keep their caches coherent?
Andreas.
--
Andreas Schwab, SUSE Labs, schwab@suse.de
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