Re: [RFC v2 03/18] kthread: Add drain_kthread_worker()
From: Tejun Heo <tj@kernel.org>
Date: 2015-09-22 18:27:09
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linux-mm, lkml
On Mon, Sep 21, 2015 at 03:03:44PM +0200, Petr Mladek wrote:
flush_kthread_worker() returns when the currently queued works are proceed.
^ processed?
But some other works might have been queued in the meantime.
...
+/** + * drain_kthread_worker - drain a kthread worker + * @worker: worker to be drained + * + * Wait until there is none work queued for the given kthread worker.
^
no
+ * Only currently running work on @worker can queue further work items
^^^^^^^^^ should be queueing is prolly more accurate
+ * on it. @worker is flushed repeatedly until it becomes empty. + * The number of flushing is determined by the depth of chaining + * and should be relatively short. Whine if it takes too long. + * + * The caller is responsible for blocking all existing works + * from an infinite re-queuing!
The caller is responsible for preventing the existing work items from requeueing themselves indefinitely.
+ * + * Also the caller is responsible for blocking all the kthread + * worker users from queuing any new work. It is especially + * important if the queue has to stay empty once this function + * finishes.
The last sentence reads a bit weird to me. New work items just aren't allowed while draining. It isn't "especially important" for certain cases. It's just buggy otherwise. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>