From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934544AbdCVPAl (ORCPT ); Wed, 22 Mar 2017 11:00:41 -0400 Received: from mail-yw0-f169.google.com ([209.85.161.169]:33676 "EHLO mail-yw0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759879AbdCVPAc (ORCPT ); Wed, 22 Mar 2017 11:00:32 -0400 Date: Wed, 22 Mar 2017 11:00:29 -0400 From: Tejun Heo To: NeilBrown Cc: Christoph Lameter , linux-kernel@vger.kernel.org, Shaohua Li , Linux-RAID Subject: Re: [PATCH] percpu-refcount: support synchronous switch to atomic mode. Message-ID: <20170322150029.GA7532@htj.duckdns.org> References: <87o9wuaxm3.fsf@notabene.neil.brown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87o9wuaxm3.fsf@notabene.neil.brown.name> User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 22, 2017 at 12:50:12PM +1100, NeilBrown wrote: > > percpu_ref_switch_to_atomic_sync() schedules the switch > to atomic mode, then waits for it to complete. > > Also export percpu_ref_switch_to_* so they can be used from modules. > > This will be used in md/raid to count the number of pending write > requests to an array. > We occasionally need to check if the count is zero, but most often > we don't care. > We always want updates to the counter to be fast, as in some cases > we count every 4K page. > > Signed-off-by: NeilBrown Acked-by: Tejun Heo Please feel free to route through other patches through md tree. If preferable, I can route it through percpu/for-4.12. Thanks. -- tejun