Re: [patch] cpufreq: mark cpufreq_tsc() as core_initcall_sync
From: Oleg Nesterov
Date: Sat Nov 18 2006 - 13:47:43 EST
On 11/17, Paul E. McKenney wrote:
>
> Oleg, any thoughts about Jens's optimization? He would code something
> like:
>
> if (srcu_readers_active(&my_srcu))
> synchronize_srcu();
> else
> smp_mb();
Well, this is clearly racy, no? I am not sure, but may be we can do
smp_mb();
if (srcu_readers_active(&my_srcu))
synchronize_srcu();
in this case we also need to add 'smp_mb()' into srcu_read_lock() after
'atomic_inc(&sp->hardluckref)'.
> However, he is doing ordered I/O requests rather than protecting data
> structures.
Probably this makes a difference, but I don't understand this.
Oleg.
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