On Thu, May 8, 2014 at 12:37 AM, Frederic Weisbecker <fweis...@gmail.com> wrote:
> Allow to modify the low-level unbound workqueues cpumask through
> sysfs. This is performed by traversing the entire workqueue list
> and calling apply_workqueue_attrs() on the unbound workqueues.
>
> Cc: Christoph Lameter <c...@linux.com>
> Cc: Kevin Hilman <khil...@linaro.org>
> Cc: Lai Jiangshan <la...@cn.fujitsu.com>
> Cc: Mike Galbraith <bitbuc...@online.de>
> Cc: Paul E. McKenney <paul...@linux.vnet.ibm.com>
> Cc: Tejun Heo <t...@kernel.org>
> Cc: Viresh Kumar <viresh.ku...@linaro.org>
> Signed-off-by: Frederic Weisbecker <fweis...@gmail.com>
> ---
> kernel/workqueue.c | 65
> ++++++++++++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 63 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index 2aa296d..5978cee 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -293,7 +293,7 @@ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects
> wq->maydays list */
> static LIST_HEAD(workqueues); /* PL: list of all workqueues */
> static bool workqueue_freezing; /* PL: have wqs started
> freezing? */
>
> -static cpumask_var_t wq_unbound_cpumask;
> +static cpumask_var_t wq_unbound_cpumask; /* PL: low level cpumask for all
> unbound wqs */
>
> /* the per-cpu worker pools */
> static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool
> [NR_STD_WORKER_POOLS],
> @@ -4084,19 +4084,80 @@ static struct bus_type wq_subsys = {
> .dev_groups = wq_sysfs_groups,
> };
>
> +static int unbounds_cpumask_apply(cpumask_var_t cpumask)
> +{
> + struct workqueue_struct *wq;
> + int ret;
> +
> + lockdep_assert_held(&wq_pool_mutex);
> +
> + list_for_each_entry(wq, &workqueues, list) {
> + struct workqueue_attrs *attrs;
> +
> + if (!(wq->flags & WQ_UNBOUND))
> + continue;
> +
> + attrs = wq_sysfs_prep_attrs(wq);
> + if (!attrs)
> + return -ENOMEM;
> +
> + ret = apply_workqueue_attrs_locked(wq, attrs, cpumask);
> + free_workqueue_attrs(attrs);
> + if (ret)
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static ssize_t unbounds_cpumask_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + cpumask_var_t cpumask;
> + int ret = -EINVAL;
> +
> + if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL))
> + return -ENOMEM;
> +
> + ret = cpumask_parse(buf, cpumask);
> + if (ret)
> + goto out;
cpumask_and(cpumask, cpumask, cpu_possible_mask);
> +
> + get_online_cpus();
> + if (cpumask_intersects(cpumask, cpu_online_mask)) {
> + mutex_lock(&wq_pool_mutex);
> + ret = unbounds_cpumask_apply(cpumask);
> + if (ret < 0) {
> + /* Warn if rollback itself fails */
> +
> WARN_ON_ONCE(unbounds_cpumask_apply(wq_unbound_cpumask));
> + } else {
> + cpumask_copy(wq_unbound_cpumask, cpumask);
> + }
> + mutex_unlock(&wq_pool_mutex);
> + }
> + put_online_cpus();
> +out:
> + free_cpumask_var(cpumask);
> + return ret ? ret : count;
> +}
> +
> static ssize_t unbounds_cpumask_show(struct device *dev,
> struct device_attribute *attr, char *buf)
> {
> int written;
>
> + mutex_lock(&wq_pool_mutex);
> written = cpumask_scnprintf(buf, PAGE_SIZE, wq_unbound_cpumask);
> + mutex_unlock(&wq_pool_mutex);
> +
> written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
>
> return written;
> }
>
> static struct device_attribute wq_sysfs_cpumask_attr =
> - __ATTR(cpumask, 0444, unbounds_cpumask_show, NULL);
> + __ATTR(cpumask, 0644, unbounds_cpumask_show, unbounds_cpumask_store);
>
> static int __init wq_sysfs_init(void)
> {
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
