----- On Jul 2, 2015, at 2:35 PM, Ingo Molnar mi...@kernel.org wrote:
> * Paul E. McKenney <paul...@linux.vnet.ibm.com> wrote:
>
>> > And it's not like it's that hard to stem the flow of algorithmic
>> > sloppiness at
>> > the source, right?
>>
>> OK, first let me make sure that I understand what you are asking for:
>>
>> 1. Completely eliminate synchronize_rcu_expedited() and
>> synchronize_sched_expedited(), replacing all uses with their
>> unexpedited counterparts. (Note that synchronize_srcu_expedited()
>> does not wake up CPUs, courtesy of its read-side memory barriers.)
>> The fast-boot guys are probably going to complain, along with
>> the networking guys.
>>
>> 2. Keep synchronize_rcu_expedited() and synchronize_sched_expedited(),
>> but push back hard on any new uses and question any existing uses.
>>
>> 3. Revert 74b51ee152b6 ("ACPI / osl: speedup grace period in
>> acpi_os_map_cleanup").
>>
>> 4. Something else?
>
> I'd love to have 1) but 2) would be a realistic second best option? ;-)
Perhaps triggering a printk warning if use of
synchronize_{rcu,sched}_expedited() go beyond of certain rate might be
another option ? If we detect that a caller calls it too often, we could
emit a printk warning with a stack trace. This should ensure everyone
is very careful about where they use it.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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