Messages in this thread | | | Date | Thu, 8 May 2014 21:20:45 +0800 | Subject | Re: [PATCH 6/6] workqueue: Record real per-workqueue cpumask | From | Lai Jiangshan <> |
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On Thu, May 8, 2014 at 12:37 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > The real cpumask set by the user on WQ_SYSFS workqueues fails to be > recorded as is: What is actually recorded as per workqueue attribute > is the per workqueue cpumask intersected with the global unbounds cpumask. > > Eventually when the user overwrites a WQ_SYSFS cpumask and later read > this attibute, the value returned is not the last one written. > > The other bad side effect is that widening the global unbounds cpumask > doesn't actually widen the unbound workqueues affinity because their > own cpumask has been schrinked. > > In order to fix this, lets record the real per workqueue cpumask on the > workqueue struct. We restore this value when attributes are re-evaluated > later. > > FIXME: Maybe I should rather invert that. Have the user set workqueue > cpumask on attributes and the effective one on the workqueue struct instead. > We'll just need some tweaking in order to make the attributes of lower layers > (pools, worker pools, worker, ...) to inherit the effective cpumask and not > the user one. > > Cc: Christoph Lameter <cl@linux.com> > Cc: Kevin Hilman <khilman@linaro.org> > Cc: Lai Jiangshan <laijs@cn.fujitsu.com> > Cc: Mike Galbraith <bitbucket@online.de> > Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> > Cc: Tejun Heo <tj@kernel.org> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > --- > kernel/workqueue.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/kernel/workqueue.c b/kernel/workqueue.c > index 5978cee..504cf0a 100644 > --- a/kernel/workqueue.c > +++ b/kernel/workqueue.c > @@ -248,6 +248,7 @@ struct workqueue_struct { > int saved_max_active; /* WQ: saved pwq max_active */ > > struct workqueue_attrs *unbound_attrs; /* WQ: only for unbound wqs */ > + cpumask_var_t saved_cpumask; /* WQ: only for unbound wqs */
Forgot to use it? or use it in next patches?
> struct pool_workqueue *dfl_pwq; /* WQ: only for unbound wqs */ > > #ifdef CONFIG_SYSFS > @@ -3694,6 +3695,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, > mutex_lock(&wq->mutex); > > copy_workqueue_attrs(wq->unbound_attrs, new_attrs); > + cpumask_copy(wq->saved_cpumask, attrs->cpumask);
I think you can use ->unbound_attrs directly: copy_workqueue_attrs(wq->unbound_attrs, attrs);
and update wq_update_unbound_numa(): copy_workqueue_attrs(tmp_attrs, wq->unbound_attrs); cpumask_and(&tmp_attrs->cpumask, wq_unbound_cpumask)
use tmp_attr instead of wq->unbound_attrs in the left code of wq_update_unbound_numa()
> > /* save the previous pwq and install the new one */ > for_each_node(node) > @@ -4326,6 +4328,11 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, > wq->unbound_attrs = alloc_workqueue_attrs(GFP_KERNEL); > if (!wq->unbound_attrs) > goto err_free_wq; > + > + if (!alloc_cpumask_var(&wq->saved_cpumask, GFP_KERNEL)) > + goto err_free_wq; > + > + cpumask_copy(wq->saved_cpumask, cpu_possible_mask); > } > > va_start(args, lock_name); > @@ -4397,6 +4404,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, > return wq; > > err_free_wq: > + free_cpumask_var(wq->saved_cpumask); > free_workqueue_attrs(wq->unbound_attrs); > kfree(wq); > return NULL; > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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