Re: [patch 11/17] Implement immediate update via stop_machine_run

[KOSAKI Motohiro]

Hi  Mathieu,
> > it seems this patch is must, Why do you separate patch [10/17] and [11/17]?
> > this patch remove almost portion of [10/17].
> > IMHO these patch merge into 1 patch is better.
> >
> >     
>
> Hi Kosaki,
>
> You are right, I will merge them and resend them in the following post.
>   
Thanks

> > > +static int stop_machine_imv_update(void *imv_ptr)
> > > +{
> > > +	struct __imv *imv = imv_ptr;
> > > +
> > > +	if (!wrote_text) {
> > >       
> > it seems racy.
> > Why don't need test_and_set?
> >
> > I think your stop_machine_run(ALL_CPUS) call fn concurrency...
> >     
> The answer to this mistery is in include/linux/stop_machine.h modified
> by add-all-cpus-option-to-stop-machine-run.patch :
>
>
>  /**
>   * stop_machine_run: freeze the machine on all CPUs and run this function
>   * @fn: the function to run
>   * @data: the data ptr for the @fn()
> - * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
> + * @cpu: if @cpu == n, run @fn() on cpu n
> + *       if @cpu == NR_CPUS, run @fn() on any cpu
> + *       if @cpu == ALL_CPUS, run @fn() first on the calling cpu, and then
> + *       concurrently on all the other cpus
>   *
>   * Description: This causes a thread to be scheduled on every other cpu,
>   * each of which disables interrupts, and finally interrupts are disabled
>
> Therefore, the first execution of the function is done before all other
> executions.
>
>   
Ah, OK. I understand.
Thanks.


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