From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [PATCH v6] DAX: enable iostat for read/write Date: Fri, 13 Jan 2017 14:54:06 -0800 Message-ID: <20170113145406.b1f065fb7fda67fd18830969@linux-foundation.org> References: <20170113233418.32252-1-toshi.kani@hpe.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20170113233418.32252-1-toshi.kani-ZPxbGqLxI0U@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Toshi Kani Cc: linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org, david-FqsqvQoI3Ljby3iVrkZq2A@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Joe Perches , viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-nvdimm@lists.01.org On Fri, 13 Jan 2017 16:34:18 -0700 Toshi Kani wrote: > DAX IO path does not support iostat, but its metadata IO path does. > Therefore, iostat shows metadata IO statistics only, which has been > confusing to users. > > Add iostat support to the DAX read/write path. > > Note, iostat still does not support the DAX mmap path as it allows > user applications to access directly. > > ... > > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1058,12 +1058,24 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, > { > struct address_space *mapping = iocb->ki_filp->f_mapping; > struct inode *inode = mapping->host; > + struct gendisk *disk = inode->i_sb->s_bdev->bd_disk; > loff_t pos = iocb->ki_pos, ret = 0, done = 0; > unsigned flags = 0; > + unsigned long start = 0; > + int do_acct = blk_queue_io_stat(disk->queue); (The poorly named) blk_queue_io_stat() actually returns a bool. This is well concealed because blk_queue_io_stat() is unnecessarily implemented as a macro (why oh why). --- a/fs/dax.c~dax-enable-iostat-for-read-write-fix +++ a/fs/dax.c @@ -1085,7 +1085,7 @@ dax_iomap_rw(struct kiocb *iocb, struct loff_t pos = iocb->ki_pos, ret = 0, done = 0; unsigned flags = 0; unsigned long start = 0; - int do_acct = blk_queue_io_stat(disk->queue); + bool do_acct = blk_queue_io_stat(disk->queue); if (iov_iter_rw(iter) == WRITE) flags |= IOMAP_WRITE; _ From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:48770 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751486AbdAMWyI (ORCPT ); Fri, 13 Jan 2017 17:54:08 -0500 Date: Fri, 13 Jan 2017 14:54:06 -0800 From: Andrew Morton To: Toshi Kani Cc: dan.j.williams@intel.com, david@fromorbit.com, viro@zeniv.linux.org.uk, ross.zwisler@linux.intel.com, linux-nvdimm@ml01.01.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, Joe Perches Subject: Re: [PATCH v6] DAX: enable iostat for read/write Message-Id: <20170113145406.b1f065fb7fda67fd18830969@linux-foundation.org> In-Reply-To: <20170113233418.32252-1-toshi.kani@hpe.com> References: <20170113233418.32252-1-toshi.kani@hpe.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Fri, 13 Jan 2017 16:34:18 -0700 Toshi Kani wrote: > DAX IO path does not support iostat, but its metadata IO path does. > Therefore, iostat shows metadata IO statistics only, which has been > confusing to users. > > Add iostat support to the DAX read/write path. > > Note, iostat still does not support the DAX mmap path as it allows > user applications to access directly. > > ... > > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1058,12 +1058,24 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, > { > struct address_space *mapping = iocb->ki_filp->f_mapping; > struct inode *inode = mapping->host; > + struct gendisk *disk = inode->i_sb->s_bdev->bd_disk; > loff_t pos = iocb->ki_pos, ret = 0, done = 0; > unsigned flags = 0; > + unsigned long start = 0; > + int do_acct = blk_queue_io_stat(disk->queue); (The poorly named) blk_queue_io_stat() actually returns a bool. This is well concealed because blk_queue_io_stat() is unnecessarily implemented as a macro (why oh why). --- a/fs/dax.c~dax-enable-iostat-for-read-write-fix +++ a/fs/dax.c @@ -1085,7 +1085,7 @@ dax_iomap_rw(struct kiocb *iocb, struct loff_t pos = iocb->ki_pos, ret = 0, done = 0; unsigned flags = 0; unsigned long start = 0; - int do_acct = blk_queue_io_stat(disk->queue); + bool do_acct = blk_queue_io_stat(disk->queue); if (iov_iter_rw(iter) == WRITE) flags |= IOMAP_WRITE; _