From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay1.corp.sgi.com [137.38.102.111]) by oss.sgi.com (Postfix) with ESMTP id 434177F5A for ; Tue, 1 Dec 2015 13:41:48 -0600 (CST) Received: from cuda.sgi.com (cuda1.sgi.com [192.48.157.11]) by relay1.corp.sgi.com (Postfix) with ESMTP id 25BEE8F8033 for ; Tue, 1 Dec 2015 11:41:44 -0800 (PST) Received: from bombadil.infradead.org ([198.137.202.9]) by cuda.sgi.com with ESMTP id heD42n2SAHbLgBN1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO) for ; Tue, 01 Dec 2015 11:41:41 -0800 (PST) Date: Tue, 1 Dec 2015 11:41:39 -0800 From: Christoph Hellwig Subject: Re: sleeps and waits during io_submit Message-ID: <20151201194139.GA19035@infradead.org> References: <20151201131114.GA26129@bfoster.bfoster> <565DA784.5080003@scylladb.com> <20151201145631.GD26129@bfoster.bfoster> <565DBB3E.2010308@scylladb.com> <20151201160133.GE26129@bfoster.bfoster> <565DC613.4090608@scylladb.com> <20151201162958.GF26129@bfoster.bfoster> <565DD449.5090101@scylladb.com> <20151201185113.GG26129@bfoster.bfoster> <565DF472.8080101@scylladb.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <565DF472.8080101@scylladb.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Avi Kivity Cc: Brian Foster , Glauber Costa , xfs@oss.sgi.com On Tue, Dec 01, 2015 at 09:26:42PM +0200, Avi Kivity wrote: > It's basically the same thing. To to this, we'd have get_block either > return the block's address (if it was in some metadata cache), or, if it was > not, issue an I/O that fills (part of) that cache, and as its completion > function, a continuation that reruns __blockdev_direct_IO from the point it > was stopped so it can submit the data I/O (if the metadata cache was > completely updated) or issue the next I/O aiming to fill that metadata > cache, if it was not. We did something this for blocking reads with great results, and it could be done similarly for direct I/O I think: https://lwn.net/Articles/612483/ Unfortunately Andrew shut it down for odd reasons so it didn't get in. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs