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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-04 04:00:13 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-04 04:00:13 +0300
commitd92cd810e64aa7cf22b05f0ea1c7d3e8dbae75fe (patch)
tree592e040010a30d1dbce4e54eb597011af0df290e /kernel
parenta23867f1d2de572f84b459651dfe99fa9e79fadf (diff)
parentf75da8a8a918d7c343a2ec95d1ed99e5689e0f23 (diff)
downloadlinux-d92cd810e64aa7cf22b05f0ea1c7d3e8dbae75fe.tar.xz
Merge branch 'for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue updates from Tejun Heo: "rcu_work addition and a couple trivial changes" * 'for-4.17' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: remove the comment about the old manager_arb mutex workqueue: fix the comments of nr_idle fs/aio: Use rcu_work instead of explicit rcu and work item cgroup: Use rcu_work instead of explicit rcu and work item RCU, workqueue: Implement rcu_work
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cgroup/cgroup.c21
-rw-r--r--kernel/workqueue.c60
2 files changed, 63 insertions, 18 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 4bfb2908ec15..a662bfcbea0e 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4524,10 +4524,10 @@ static struct cftype cgroup_base_files[] = {
* and thus involve punting to css->destroy_work adding two additional
* steps to the already complex sequence.
*/
-static void css_free_work_fn(struct work_struct *work)
+static void css_free_rwork_fn(struct work_struct *work)
{
- struct cgroup_subsys_state *css =
- container_of(work, struct cgroup_subsys_state, destroy_work);
+ struct cgroup_subsys_state *css = container_of(to_rcu_work(work),
+ struct cgroup_subsys_state, destroy_rwork);
struct cgroup_subsys *ss = css->ss;
struct cgroup *cgrp = css->cgroup;
@@ -4573,15 +4573,6 @@ static void css_free_work_fn(struct work_struct *work)
}
}
-static void css_free_rcu_fn(struct rcu_head *rcu_head)
-{
- struct cgroup_subsys_state *css =
- container_of(rcu_head, struct cgroup_subsys_state, rcu_head);
-
- INIT_WORK(&css->destroy_work, css_free_work_fn);
- queue_work(cgroup_destroy_wq, &css->destroy_work);
-}
-
static void css_release_work_fn(struct work_struct *work)
{
struct cgroup_subsys_state *css =
@@ -4631,7 +4622,8 @@ static void css_release_work_fn(struct work_struct *work)
mutex_unlock(&cgroup_mutex);
- call_rcu(&css->rcu_head, css_free_rcu_fn);
+ INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+ queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
}
static void css_release(struct percpu_ref *ref)
@@ -4765,7 +4757,8 @@ static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
err_list_del:
list_del_rcu(&css->sibling);
err_free_css:
- call_rcu(&css->rcu_head, css_free_rcu_fn);
+ INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
+ queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
return ERR_PTR(err);
}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 254e636a3d6b..ca7959be8aaa 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -153,10 +153,9 @@ struct worker_pool {
unsigned long watchdog_ts; /* L: watchdog timestamp */
struct list_head worklist; /* L: list of pending works */
- int nr_workers; /* L: total number of workers */
- /* nr_idle includes the ones off idle_list for rebinding */
- int nr_idle; /* L: currently idle ones */
+ int nr_workers; /* L: total number of workers */
+ int nr_idle; /* L: currently idle workers */
struct list_head idle_list; /* X: list of idle workers */
struct timer_list idle_timer; /* L: worker idle timeout */
@@ -166,7 +165,6 @@ struct worker_pool {
DECLARE_HASHTABLE(busy_hash, BUSY_WORKER_HASH_ORDER);
/* L: hash of busy workers */
- /* see manage_workers() for details on the two manager mutexes */
struct worker *manager; /* L: purely informational */
struct mutex attach_mutex; /* attach/detach exclusion */
struct list_head workers; /* A: attached workers */
@@ -1604,6 +1602,40 @@ bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq,
}
EXPORT_SYMBOL_GPL(mod_delayed_work_on);
+static void rcu_work_rcufn(struct rcu_head *rcu)
+{
+ struct rcu_work *rwork = container_of(rcu, struct rcu_work, rcu);
+
+ /* read the comment in __queue_work() */
+ local_irq_disable();
+ __queue_work(WORK_CPU_UNBOUND, rwork->wq, &rwork->work);
+ local_irq_enable();
+}
+
+/**
+ * queue_rcu_work - queue work after a RCU grace period
+ * @wq: workqueue to use
+ * @rwork: work to queue
+ *
+ * Return: %false if @rwork was already pending, %true otherwise. Note
+ * that a full RCU grace period is guaranteed only after a %true return.
+ * While @rwork is guarnateed to be executed after a %false return, the
+ * execution may happen before a full RCU grace period has passed.
+ */
+bool queue_rcu_work(struct workqueue_struct *wq, struct rcu_work *rwork)
+{
+ struct work_struct *work = &rwork->work;
+
+ if (!test_and_set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(work))) {
+ rwork->wq = wq;
+ call_rcu(&rwork->rcu, rcu_work_rcufn);
+ return true;
+ }
+
+ return false;
+}
+EXPORT_SYMBOL(queue_rcu_work);
+
/**
* worker_enter_idle - enter idle state
* @worker: worker which is entering idle state
@@ -3001,6 +3033,26 @@ bool flush_delayed_work(struct delayed_work *dwork)
}
EXPORT_SYMBOL(flush_delayed_work);
+/**
+ * flush_rcu_work - wait for a rwork to finish executing the last queueing
+ * @rwork: the rcu work to flush
+ *
+ * Return:
+ * %true if flush_rcu_work() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_rcu_work(struct rcu_work *rwork)
+{
+ if (test_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&rwork->work))) {
+ rcu_barrier();
+ flush_work(&rwork->work);
+ return true;
+ } else {
+ return flush_work(&rwork->work);
+ }
+}
+EXPORT_SYMBOL(flush_rcu_work);
+
static bool __cancel_work(struct work_struct *work, bool is_dwork)
{
unsigned long flags;