On Tue, Aug 4, 2015 at 5:18 AM, Scott Wood <scottw...@freescale.com>
wrote:
[Added linuxppc-...@lists.ozlabs.org. Besides that list being
required for
review of PPC patches, it feeds the patchwork that I use to track and
apply
patches.]
On Mon, 2015-08-03 at 19:52 +0800, Chenhui Zhao wrote:
On Sat, Aug 1, 2015 at 8:14 AM, Scott Wood <scottw...@freescale.com>
wrote:
> On Fri, 2015-07-31 at 17:20 +0800, b29983@freescale.comwrote:
> > From: Tang Yuantian <yuantian.t...@freescale.com>
> >
> > Freescale E500MC and E5500 core-based platforms, like P4080,
T1040,
> > support disabling/enabling CPU dynamically.
> > This patch adds this feature on those platforms.
> >
> > Signed-off-by: Chenhui Zhao <chenhui.z...@freescale.com>
> > Signed-off-by: Tang Yuantian <yuantian.t...@feescale.com>
+{
> > + int i;
> > +
> > + for (i = 0; i < 50000; i++) {
> > + if (generic_check_cpu_dead(cpu)) {
> > + qoriq_pm_ops->cpu_die(cpu);
> > +#ifdef CONFIG_PPC64
> > + paca[cpu].cpu_start = 0;
> > +#endif
> > + return;
> > + }
> > + udelay(10);
> > + }
> > + pr_err("%s: CPU%d didn't die...\n", __func__, cpu);
> > +}
>
> Only 500ms timeout, versus 10sec in generic_cpu_die()?
The process is fast. Maybe 10 second is too large.
Is it fast 100% of the time? What if the CPU you intend to die is in
a long
critical section? What harm is there to having a longer timeout,
similar to
what other platforms use?
Will change the max timeout to 10 seconds.
>
> > #endif
> >
> > static inline void flush_spin_table(void *spin_table)
> > @@ -246,11 +267,7 @@ static int smp_85xx_kick_cpu(int nr)
> > spin_table = phys_to_virt(*cpu_rel_addr);
> >
> > local_irq_save(flags);
> > -#ifdef CONFIG_PPC32
> > #ifdef CONFIG_HOTPLUG_CPU
> > - /* Corresponding to generic_set_cpu_dead() */
> > - generic_set_cpu_up(nr);
> > -
> > if (system_state == SYSTEM_RUNNING) {
> > /*
> > * To keep it compatible with old boot program
which
> > uses
> > @@ -263,6 +280,7 @@ static int smp_85xx_kick_cpu(int nr)
> > out_be32(&spin_table->addr_l, 0);
> > flush_spin_table(spin_table);
> >
> > + qoriq_pm_ops->cpu_up(nr);
>
> Again, is it possible to get here without a valid qoriq_pm_ops
(i.e.
> is there
> anything stopping the user from trying to initiate CPU hotplug)?
>
> -Scott
For every platform running this code, should has a valid
qoriq_pm_ops.
If not valid, it's a bug.
How do you prevent this code from running when there is no valid
qoriq_pm_ops?
-Scott
Will check if qoriq_pm_ops is valid.
-Chenhui
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