From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ea0-f173.google.com ([209.85.215.173]:34846 "EHLO mail-ea0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775Ab3IZOQK (ORCPT ); Thu, 26 Sep 2013 10:16:10 -0400 Date: Thu, 26 Sep 2013 16:16:06 +0200 From: Ingo Molnar To: Josef Bacik Cc: linux-btrfs@vger.kernel.org, walken@google.com, linux-kernel@vger.kernel.org, peter@hurleysoftware.com, akpm@linux-foundation.org Subject: Re: [PATCH 1/2] rwsem: add rwsem_is_contended V3 Message-ID: <20130926141606.GA32444@gmail.com> References: <1380201996-17445-1-git-send-email-jbacik@fusionio.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1380201996-17445-1-git-send-email-jbacik@fusionio.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: * Josef Bacik wrote: > Btrfs needs a simple way to know if it needs to let go of it's read lock on a > rwsem. Introduce rwsem_is_contended to check to see if there are any waiters on > this rwsem currently. This is just a hueristic, it is meant to be light and not > 100% accurate and called by somebody already holding on to the rwsem in either > read or write. Thanks, > > Signed-off-by: Josef Bacik Acked-by: Ingo Molnar Thanks, Ingo