Lai Jiangshan <[email protected]> writes:
> From: Frederic Weisbecker <[email protected]>
>
> Create a cpumask that limit the affinity of all unbound workqueues.
> This cpumask is controlled though a file at the root of the workqueue
> sysfs directory.
>
> It works on a lower-level than the per WQ_SYSFS workqueues cpumask files
> such that the effective cpumask applied for a given unbound workqueue is
> the intersection of /sys/devices/virtual/workqueue/$WORKQUEUE/cpumask and
> the new /sys/devices/virtual/workqueue/cpumask_unbounds file.
>
> This patch implements the basic infrastructure and the read interface.
> cpumask_unbounds is initially set to cpu_possible_mask.
>
> Cc: Christoph Lameter <[email protected]>
> Cc: Kevin Hilman <[email protected]>
> Cc: Lai Jiangshan <[email protected]>
> Cc: Mike Galbraith <[email protected]>
> Cc: Paul E. McKenney <[email protected]>
> Cc: Tejun Heo <[email protected]>
> Cc: Viresh Kumar <[email protected]>
> Signed-off-by: Frederic Weisbecker <[email protected]>
> Signed-off-by: Lai Jiangshan <[email protected]>
[...]
> @@ -5094,6 +5116,9 @@ static int __init init_workqueues(void)
>
> WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long));
>
> + BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL));
> + cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
> +
As I mentioned in an earlier discussion[1], I still think this could
default too the housekeeping CPUs in the NO_HZ_FULL case:
#ifdef CONFIG_NO_HZ_FULL
cpumask_complement(wq_unbound_cpumask, tick_nohz_full_mask);
#else
cpumask_copy(wq_unbound_cpumask, cpu_possible_mask);
#endif
But that could also be left to a future optimization as well.
Kevin
[1] https://lkml.org/lkml/2014/2/14/666
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