From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-fsdevel-owner@vger.kernel.org>
Received: from smtp.codeaurora.org ([198.145.29.96]:45151 "EHLO
	smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1753001AbcC3SZ6 (ORCPT
	<rfc822;linux-fsdevel@vger.kernel.org>);
	Wed, 30 Mar 2016 14:25:58 -0400
Message-ID: <56FC1A2F.5090504@codeaurora.org>
Date: Wed, 30 Mar 2016 11:25:51 -0700
From: Nikhilesh Reddy <reddyn@codeaurora.org>
MIME-Version: 1.0
To: Al Viro <viro@zeniv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Downsides to using synchronize_rcu_expedited instead if synchronize_rcu
 in namespace_unlock
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

Hi
I was wondering why namespace_unlock calls synchronize_rcu and not 
synchronize_rcu_expedited

Testing shows there is about 20-25 ms saved during an unmount when using 
synchronize_rcu_expedited

is there a downside to such a change?

Please let me know.
I would really appreciate any help understanding any pitfalls.

-- 
Thanks
Nikhilesh Reddy

Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.