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Date: Tue, 19 Jul 2011 12:53:45 -0400
From: Christoph Hellwig <hch@infradead.org>
To: Curt Wohlgemuth <curtw@google.com>
Cc: Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@infradead.org>,
        Al Viro <viro@zeniv.linux.org.uk>, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, fengguang.wu@intel.com
Subject: Re: [PATCH] writeback: Don't wait for completion in
 writeback_inodes_sb_nr
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On Thu, Jul 14, 2011 at 09:29:34AM -0700, Curt Wohlgemuth wrote:
> Your patch looks good to me, in that it does hit all the bdevs with
> both WB_SYNC_NONE and SYNC_ALL.  However, I still say that the call to
> wakeup_flusher_threads() in sys_sync() is superfluous, at least as
> long as writeback_inodes_sb() waits for completion of the work item
> that it enqueues.

Commit 3beab0b42413e83a7907db7176b54c840fc75a81

	"sys_sync(): fix 16% performance regression in ffsb create_4k test"

suggests we need the wakeup_flusher_threads.  We might be able to get
rid of the writeback_inodes_sb call if we're lucky.