From mboxrd@z Thu Jan  1 00:00:00 1970
From: Akira Hayakawa <ruby.wktk@gmail.com>
Subject: Re: [PATCH 1/1] improve the performance of
	dm-log-userspace
Date: Thu, 21 Nov 2013 19:26:31 +0900
Message-ID: <528DDFD7.6040005@gmail.com>
References: <d1a7ba26f5e515d635eb3f1d65315c4050bda7ae.1385021669.git.dmzhang@suse.com>
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Hi, Dongmao

I think you are using workqueue the wrong way in two places.

1)
WQ_NON_REENTRANT is deprecated. You should remove it.
> +	if (lc->integrated_flush) {
> +		lc->dmlog_wq = alloc_workqueue("dmlogd", WQ_NON_REENTRANT | WQ_MEM_RECLAIM, 0);

2)
destory_workqueue first calls drain_workqueue which
then calls flush_workqueue. You should remove the first line of these.
> +		flush_workqueue(lc->dmlog_wq);
> +		destroy_workqueue(lc->dmlog_wq);

Akira