From: Ted Ts'o Subject: Re: [PATCH, RFC 2/3] jbd2: Change j_state_lock to be a rwlock_t Date: Tue, 3 Aug 2010 20:08:39 -0400 Message-ID: <20100804000839.GI9453@thunk.org> References: <1280851315-9167-1-git-send-email-tytso@mit.edu> <1280851315-9167-3-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: John Stultz , Keith Maanthey , Eric Whitney To: Ext4 Developers List , ocfs2-devel@oss.oracle.com Return-path: Received: from thunk.org ([69.25.196.29]:32809 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757344Ab0HDAIl (ORCPT ); Tue, 3 Aug 2010 20:08:41 -0400 Content-Disposition: inline In-Reply-To: <1280851315-9167-3-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Aug 03, 2010 at 12:01:54PM -0400, Theodore Ts'o wrote: > Lockstat reports have shown that j_state_lock is a major source of > lock contention, especially on systems with more than 4 CPU cores. So > change it to be a read/write spinlock. > > Signed-off-by: "Theodore Ts'o" Oops, this patch can result in a BUG_ON in fs/jbd2/transaction.c. I'm currently testing a fix/replacement patch, but I figured I send a quick warning to folks not to waste time trying this out just yet. I should hopefully have a new, better-tested patch in by tomorrow morning. - Ted