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;
+
+ 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
--
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