From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ankit Jain Subject: [LSF/MM TOPIC][ATTEND] Improving async io, specifically io_submit latencies Date: Fri, 01 Mar 2013 01:37:55 +0530 Message-ID: <512FB91B.80102@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Jan Kara , Zach Brown To: lsf-pc@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org Return-path: Received: from cantor2.suse.de ([195.135.220.15]:51871 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752585Ab3B1UIA (ORCPT ); Thu, 28 Feb 2013 15:08:00 -0500 Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hi, I'm interested in discussing how to improve async io api in the kernel, specifically io_submit latencies. I am working on trying to make io_submit non-blocking. I had posted a patch[1] for this earlier on fsdevel and there was some discussion on it. I have made some of the improvements suggested there. The approach attempted in that patch essentially tries to service the requests on a separate kernel thread. It was pointed out that this would need to ensure that there aren't any unknown task_struct references or dependencies under f_op->aio* which might get confused because of the kernel thread. Would this kinda full audit be enough or would be it considered too fragile? I would like to discuss whether this is best approach for solving this problem, and/or discuss some of the other possible approaches to solving this issue. This has been discussed in the past but we don't seem to have a solution as of now. References: 1. http://comments.gmane.org/gmane.linux.kernel.aio.general/3142 Regards, -- Ankit Jain SUSE Labs