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workqueue: update sysfs interface to reflect NUMA awareness and a kernel param to disable NUMA affinity

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Unbound workqueues are now NUMA aware.  Let's add some control knobs
and update sysfs interface accordingly.

* Add kernel param workqueue.numa_disable which disables NUMA affinity
  globally.

* Replace sysfs file "pool_id" with "pool_ids" which contain
  node:pool_id pairs.  This change is userland-visible but "pool_id"
  hasn't seen a release yet, so this is okay.

* Add a new sysf files "numa" which can toggle NUMA affinity on
  individual workqueues.  This is implemented as attrs->no_numa whichn
  is special in that it isn't part of a pool's attributes.  It only
  affects how apply_workqueue_attrs() picks which pools to use.

After "pool_ids" change, first_pwq() doesn't have any user left.
Removed.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
This commit is contained in:
Tejun Heo 2013-04-01 11:23:38 -07:00
parent 4c16bd327c
commit d55262c4d1
3 changed files with 73 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

82
kernel/workqueue.c
View file

@ -268,6 +268,9 @@ static int wq_numa_tbl_len; /* highest possible NUMA node id + 1 */
static cpumask_var_t *wq_numa_possible_cpumask;
/* possible CPUs of each node */
static bool wq_disable_numa;
module_param_named(disable_numa, wq_disable_numa, bool, 0444);
static bool wq_numa_enabled; /* unbound NUMA affinity enabled */
/* buf for wq_update_unbound_numa_attrs(), protected by CPU hotplug exclusion */
@ -516,21 +519,6 @@ static int worker_pool_assign_id(struct worker_pool *pool)
return ret;
}
/**
* first_pwq - return the first pool_workqueue of the specified workqueue
* @wq: the target workqueue
*
* This must be called either with wq->mutex held or sched RCU read locked.
* If the pwq needs to be used beyond the locking in effect, the caller is
* responsible for guaranteeing that the pwq stays online.
*/
static struct pool_workqueue *first_pwq(struct workqueue_struct *wq)
{
assert_rcu_or_wq_mutex(wq);
return list_first_or_null_rcu(&wq->pwqs, struct pool_workqueue,
pwqs_node);
}
/**
* unbound_pwq_by_node - return the unbound pool_workqueue for the given node
* @wq: the target workqueue
@ -3114,16 +3102,21 @@ static struct device_attribute wq_sysfs_attrs[] = {
__ATTR_NULL,
};
static ssize_t wq_pool_id_show(struct device *dev,
struct device_attribute *attr, char *buf)
static ssize_t wq_pool_ids_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct worker_pool *pool;
int written;
const char *delim = "";
int node, written = 0;
rcu_read_lock_sched();
pool = first_pwq(wq)->pool;
written = scnprintf(buf, PAGE_SIZE, "%d\n", pool->id);
for_each_node(node) {
written += scnprintf(buf + written, PAGE_SIZE - written,
"%s%d:%d", delim, node,
unbound_pwq_by_node(wq, node)->pool->id);
delim = " ";
}
written += scnprintf(buf + written, PAGE_SIZE - written, "\n");
rcu_read_unlock_sched();
return written;
@ -3212,10 +3205,46 @@ static ssize_t wq_cpumask_store(struct device *dev,
return ret ?: count;
}
static ssize_t wq_numa_show(struct device *dev, struct device_attribute *attr,
char *buf)
{
struct workqueue_struct *wq = dev_to_wq(dev);
int written;
mutex_lock(&wq->mutex);
written = scnprintf(buf, PAGE_SIZE, "%d\n",
!wq->unbound_attrs->no_numa);
mutex_unlock(&wq->mutex);
return written;
}
static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
int v, ret;
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
return -ENOMEM;
ret = -EINVAL;
if (sscanf(buf, "%d", &v) == 1) {
attrs->no_numa = !v;
ret = apply_workqueue_attrs(wq, attrs);
}
free_workqueue_attrs(attrs);
return ret ?: count;
}
static struct device_attribute wq_sysfs_unbound_attrs[] = {
__ATTR(pool_id, 0444, wq_pool_id_show, NULL),
__ATTR(pool_ids, 0444, wq_pool_ids_show, NULL),
__ATTR(nice, 0644, wq_nice_show, wq_nice_store),
__ATTR(cpumask, 0644, wq_cpumask_show, wq_cpumask_store),
__ATTR(numa, 0644, wq_numa_show, wq_numa_store),
__ATTR_NULL,
};
@ -3750,7 +3779,7 @@ static void free_unbound_pwq(struct pool_workqueue *pwq)
static bool wq_calc_node_cpumask(const struct workqueue_attrs *attrs, int node,
int cpu_going_down, cpumask_t *cpumask)
{
if (!wq_numa_enabled)
if (!wq_numa_enabled || attrs->no_numa)
goto use_dfl;
/* does @node have any online CPUs @attrs wants? */
@ -3951,6 +3980,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
cpumask = target_attrs->cpumask;
mutex_lock(&wq->mutex);
if (wq->unbound_attrs->no_numa)
goto out_unlock;
copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
pwq = unbound_pwq_by_node(wq, node);
@ -4763,6 +4794,11 @@ static void __init wq_numa_init(void)
if (num_possible_nodes() <= 1)
return;
if (wq_disable_numa) {
pr_info("workqueue: NUMA affinity support disabled\n");
return;
}
wq_update_unbound_numa_attrs_buf = alloc_workqueue_attrs(GFP_KERNEL);
BUG_ON(!wq_update_unbound_numa_attrs_buf);