And this pointer helps other workers know the progress of idle-rebinding.
when gcwq->idle_rebind is not NULL, it means the idle-rebinding is still
in progress.
and idle_worker_rebind() is split.
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
kernel/workqueue.c | 67 ++++++++++++++++++++++++++++++++++++++--------------
1 files changed, 49 insertions(+), 18 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9466d91..c875951 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -150,7 +150,6 @@ struct worker {
int id; /* I: worker id */
/* for rebinding worker to CPU */
- struct idle_rebind *idle_rebind; /* L: for idle worker */
struct work_struct rebind_work; /* L: for busy worker */
};
@@ -185,6 +184,9 @@ struct global_cwq {
/* L: hash of busy workers */
struct worker_pool pools[2]; /* normal and highpri pools */
+
+ /* for rebinding worker to CPU */
+ struct idle_rebind *idle_rebind; /* L or ref: for idle worker */
} ____cacheline_aligned_in_smp;
/*
@@ -1313,10 +1315,10 @@ struct idle_rebind {
/*
* notify the rebind_workers() that:
* 1. All idle workers are rebound.
- * 2. No idle worker has ref to this struct
+ * 2. No worker has ref to this struct
*
- * @ref_cnt: # idle workers which has ref to this struct
- * @ref_done: any idle workers has no ref to this struct,
+ * @ref_cnt: # workers which has ref to this struct
+ * @ref_done: any worker has no ref to this struct,
* it also implies that all idle workers are rebound.
*/
int ref_cnt;
@@ -1324,28 +1326,55 @@ struct idle_rebind {
};
/*
+ * synchronize_all_idles_rebound: wait until all idles workers are rebound
+ * @gcwq: gcwq of interest
+ * @idle_rebind: the value of @gcwq->idle_rebind, the caller should have
+ * at least one reference to it.
+ *
+ * CONTEXT:
+ * Might sleep. Called without any lock.
+ * With at least one bit of WORKER_NOT_RUNNING set if called from worker.
+ */
+static void synchronize_all_idles_rebound(struct global_cwq *gcwq,
+ struct idle_rebind *idle_rebind)
+{
+
+ /* wait for rebind_workers() to notify that all idles are rebound */
+ wait_for_completion(&idle_rebind->rebind_hold);
+
+ /* finished synchronizing, put reference */
+ spin_lock_irq(&gcwq->lock);
+ if (!--idle_rebind->ref_cnt) {
+ gcwq->idle_rebind = NULL;
+ complete(&idle_rebind->ref_done);
+ }
+ spin_unlock_irq(&gcwq->lock);
+}
+
+/*
* Rebind an idle @worker to its CPU. During CPU onlining, this has to
* happen synchronously for idle workers. worker_thread() will test
* %WORKER_REBIND before leaving idle and call this function.
*/
static void idle_worker_rebind(struct worker *worker)
{
+ struct global_cwq *gcwq = worker->pool->gcwq;
+ struct idle_rebind *idle_rebind;
+
/* CPU must be online at this point */
WARN_ON(!worker_maybe_bind_and_lock(worker));
worker_clr_flags(worker, WORKER_REBIND);
- ++worker->idle_rebind->ref_cnt;
- if (!--worker->idle_rebind->idle_cnt)
- complete(&worker->idle_rebind->idle_done);
- spin_unlock_irq(&worker->pool->gcwq->lock);
- /* we did our part, wait for rebind_workers() to finish up */
- wait_for_completion(&worker->idle_rebind->rebind_hold);
+ /* get reference */
+ idle_rebind = gcwq->idle_rebind;
+ ++idle_rebind->ref_cnt;
- /* noify if all idle worker are done(rebond & wait) */
- spin_lock_irq(&worker->pool->gcwq->lock);
- if (!--worker->idle_rebind->ref_cnt)
- complete(&worker->idle_rebind->ref_done);
- spin_unlock_irq(&worker->pool->gcwq->lock);
+ /* this worker has been rebound */
+ if (!--idle_rebind->idle_cnt)
+ complete(&idle_rebind->idle_done);
+ spin_unlock_irq(&gcwq->lock);
+
+ synchronize_all_idles_rebound(gcwq, idle_rebind);
}
/*
@@ -1414,6 +1443,7 @@ static void rebind_workers(struct global_cwq *gcwq)
init_completion(&idle_rebind.rebind_hold);
init_completion(&idle_rebind.ref_done);
idle_rebind.ref_cnt = 1;
+ gcwq->idle_rebind = &idle_rebind;
retry:
idle_rebind.idle_cnt = 1;
INIT_COMPLETION(idle_rebind.idle_done);
@@ -1429,7 +1459,6 @@ retry:
worker->flags |= WORKER_REBIND;
idle_rebind.idle_cnt++;
- worker->idle_rebind = &idle_rebind;
/* worker_thread() will call idle_worker_rebind() */
wake_up_process(worker->task);
@@ -1476,6 +1505,8 @@ retry:
spin_unlock_irq(&gcwq->lock);
wait_for_completion(&idle_rebind.ref_done);
spin_lock_irq(&gcwq->lock);
+ } else {
+ gcwq->idle_rebind = NULL;
}
}
--
1.7.4.4
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