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Date: Fri, 16 May 2014 18:16:55 +0200
From: Frederic Weisbecker <fweisbec@...il.com>
To: LKML <linux-kernel@...r.kernel.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Christoph Lameter <cl@...ux.com>,
Kevin Hilman <khilman@...aro.org>,
Lai Jiangshan <laijs@...fujitsu.com>,
Mike Galbraith <bitbucket@...ine.de>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Tejun Heo <tj@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH 5/5] workqueue: Allow modifying low level unbound workqueue cpumask
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 with
the low level mask passed in.
Cc: Christoph Lameter <cl@...ux.com>
Cc: Kevin Hilman <khilman@...aro.org>
Cc: Lai Jiangshan <laijs@...fujitsu.com>
Cc: Mike Galbraith <bitbucket@...ine.de>
Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Tejun Heo <tj@...nel.org>
Cc: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@...il.com>
---
kernel/workqueue.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 78 insertions(+), 3 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2aa296d..2a12f00 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],
@@ -3643,6 +3643,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
{
struct workqueue_attrs *new_attrs, *tmp_attrs;
struct pool_workqueue **pwq_tbl, *dfl_pwq;
+ cpumask_var_t saved_cpumask;
int node, ret;
/* only unbound workqueues can change attributes */
@@ -3653,15 +3654,25 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
if (WARN_ON((wq->flags & __WQ_ORDERED) && !attrs->no_numa))
return -EINVAL;
+ if (!alloc_cpumask_var(&saved_cpumask, GFP_KERNEL))
+ goto enomem;
+
pwq_tbl = kzalloc(wq_numa_tbl_len * sizeof(pwq_tbl[0]), GFP_KERNEL);
new_attrs = alloc_workqueue_attrs(GFP_KERNEL);
tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL);
+
if (!pwq_tbl || !new_attrs || !tmp_attrs)
goto enomem;
/* make a copy of @attrs and sanitize it */
copy_workqueue_attrs(new_attrs, attrs);
- cpumask_and(new_attrs->cpumask, new_attrs->cpumask, unbounds_cpumask);
+
+ /*
+ * Apply unbounds_cpumask on the new attrs for pwq and worker pools
+ * creation but save the wq proper cpumask for unbound attrs backup.
+ */
+ cpumask_and(saved_cpumask, new_attrs->cpumask, cpu_possible_mask);
+ cpumask_and(new_attrs->cpumask, saved_cpumask, unbounds_cpumask);
/*
* We may create multiple pwqs with differing cpumasks. Make a
@@ -3693,6 +3704,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
/* all pwqs have been created successfully, let's install'em */
mutex_lock(&wq->mutex);
+ cpumask_copy(new_attrs->cpumask, saved_cpumask);
copy_workqueue_attrs(wq->unbound_attrs, new_attrs);
/* save the previous pwq and install the new one */
@@ -3713,6 +3725,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
ret = 0;
/* fall through */
out_free:
+ free_cpumask_var(saved_cpumask);
free_workqueue_attrs(tmp_attrs);
free_workqueue_attrs(new_attrs);
kfree(pwq_tbl);
@@ -3817,6 +3830,7 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
goto out_unlock;
copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
+ cpumask_and(target_attrs->cpumask, target_attrs->cpumask, wq_unbound_cpumask);
pwq = unbound_pwq_by_node(wq, node);
/*
@@ -4084,19 +4098,80 @@ 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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