From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from verein.lst.de ([213.95.11.211]:44953 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725995AbgFBFwA (ORCPT ); Tue, 2 Jun 2020 01:52:00 -0400 Date: Tue, 2 Jun 2020 07:51:52 +0200 From: Christoph Hellwig Subject: Re: [PATCH v2] blkdev: Replace blksize_bits() with ilog2() Message-ID: <20200602055152.GA11620@lst.de> References: <20200529141100.37519-1-pilgrimtao@gmail.com> <20200601084426.GB1667318@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200601084426.GB1667318@kroah.com> Sender: linux-s390-owner@vger.kernel.org List-ID: To: Greg KH Cc: Tao pilgrim , Jens Axboe , hch@lst.de, sth@linux.ibm.com, viro@zeniv.linux.org.uk, clm@fb.com, jaegeuk@kernel.org, hch@infradead.org, Mark Fasheh , dhowells@redhat.com, balbi@kernel.org, damien.lemoal@wdc.com, bvanassche@acm.org, ming.lei@redhat.com, martin.petersen@oracle.com, satyat@google.com, chaitanya.kulkarni@wdc.com, houtao1@huawei.com, asml.silence@gmail.com, ajay.joshi@wdc.com, linux-kernel@vger.kernel.org, Muchun Song , hoeppner@linux.ibm.com, heiko.carstens@de.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, linux-s390@vger.kernel.org, sagi@grimberg.me, linux-nvme@lists.infradead.org, linux-usb@vger.kernel.org, Josef Bacik , dsterba@suse.com, linux-btrfs@vger.kernel.org, chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, darrick.wong@oracle.com, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, jlbec@evilplan.org, joseph.qi@linux.alibaba.com, ocfs2-devel@oss.oracle.com, deepa.kernel@gmail.com On Mon, Jun 01, 2020 at 10:44:26AM +0200, Greg KH wrote: > But does this code path actually show up anywhere that is actually > measurable as mattering? > > If so, please show that benchmark results. I think the requests are starting to be a bit unreasonable. Tao is replacing a reimplementation of a standard function with that standard function / compiler builtin. We don't put such a high burden on that. And once the proper existing fields are used where possible as shown in my reply just replacing the rest seems totally obvious - quite contrary I think keeping a reimplementation would need a high bar.