From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Date: Tue, 12 Oct 2010 06:01:11 +0800 Subject: [Ocfs2-devel] [PATCH 1/1] Ocfs2: Add a mount option "coherency=*" to handle cluster coherency for O_DIRECT writes. In-Reply-To: <20101011211643.GH4255@mail.oracle.com> References: <1286786799-10230-1-git-send-email-tristan.ye@oracle.com> <20101011211643.GH4255@mail.oracle.com> Message-ID: <4CB38927.2070403@oracle.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com Hi Joel, Joel Becker wrote: > On Mon, Oct 11, 2010 at 04:46:39PM +0800, Tristan Ye wrote: > >> Currently, default behavior of O_DIRECT writes was allowing >> concurrent writing among nodes, no cluster coherency guaranteed >> (no EX locks was taken), it hurts buffered reads on other nodes >> by reading stale data from cache. >> >> The new mount option introduce a chance to choose two different >> behaviors for O_DIRECT writes: >> >> * coherency=full, as the default value, will disallow >> concurrent O_DIRECT writes by taking >> EX locks. >> >> * coherency=buffered, allow concurrent O_DIRECT writes >> without EX lock among nodes, which >> gains high performance at risk of >> getting stale data on other nodes. >> >> Signed-off-by: Tristan Ye >> > > This patch is now in the merge-window branch of ocfs2.git. > I think that you agree with me that we only need to take PR lock in full_coherency, but this patch still try the exclusive one. So do I miss something? Regards, Tao