From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67D1CC433E0 for ; Thu, 25 Feb 2021 22:24:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1397564F47 for ; Thu, 25 Feb 2021 22:24:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232473AbhBYWXr (ORCPT ); Thu, 25 Feb 2021 17:23:47 -0500 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:35942 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232631AbhBYWWk (ORCPT ); Thu, 25 Feb 2021 17:22:40 -0500 Received: from dread.disaster.area (pa49-179-130-210.pa.nsw.optusnet.com.au [49.179.130.210]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id D89518284E1; Fri, 26 Feb 2021 09:21:50 +1100 (AEDT) Received: from dave by dread.disaster.area with local (Exim 4.92.3) (envelope-from ) id 1lFP14-004LA3-8D; Fri, 26 Feb 2021 09:21:50 +1100 Date: Fri, 26 Feb 2021 09:21:50 +1100 From: Dave Chinner To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 10/13] xfs: introduce xlog_write_single() Message-ID: <20210225222150.GT4662@dread.disaster.area> References: <20210224063459.3436852-1-david@fromorbit.com> <20210224063459.3436852-11-david@fromorbit.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.3 cv=YKPhNiOx c=1 sm=1 tr=0 cx=a_idp_d a=JD06eNgDs9tuHP7JIKoLzw==:117 a=JD06eNgDs9tuHP7JIKoLzw==:17 a=kj9zAlcOel0A:10 a=qa6Q16uM49sA:10 a=20KFwNOVAAAA:8 a=7-415B0cAAAA:8 a=eYN5_DQUlCCoGLnqkd0A:9 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Feb 25, 2021 at 07:43:38PM +0100, Christoph Hellwig wrote: > On Wed, Feb 24, 2021 at 05:34:56PM +1100, Dave Chinner wrote: > > From: Dave Chinner > > > > Vector out to an optimised version of xlog_write() if the entire > > s/Vector/Factor/ ? > > > + ptr = iclog->ic_datap + log_offset; > > + while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) { > > + > > + > > + /* ordered log vectors have no regions to write */ > > The two empty lines above look a little strange. > > > + if (lv->lv_buf_len == XFS_LOG_VEC_ORDERED) { > > + ASSERT(lv->lv_niovecs == 0); > > + goto next_lv; > > + } > > + > > + reg = &lv->lv_iovecp[index]; > > + ASSERT(reg->i_len % sizeof(int32_t) == 0); > > + ASSERT((unsigned long)ptr % sizeof(int32_t) == 0); > > + > > + ophdr = reg->i_addr; > > + ophdr->oh_tid = cpu_to_be32(ticket->t_tid); > > + ophdr->oh_len = cpu_to_be32(reg->i_len - > > + sizeof(struct xlog_op_header)); > > + > > + memcpy(ptr, reg->i_addr, reg->i_len); > > + xlog_write_adv_cnt(&ptr, &len, &log_offset, reg->i_len); > > + record_cnt++; > > + > > + /* move to the next iovec */ > > + if (++index < lv->lv_niovecs) > > + continue; > > +next_lv: > > + /* move to the next logvec */ > > + lv = lv->lv_next; > > + index = 0; > > + } > > I always hated this (pre-existing) loop style. Me too, but my brain was stretched just getting it factored into a tighter loop so I wasn't looking too hard at the iteration methof itself. > What do you think of > something like this (just whiteboard coding, might be completely broken), > which also handles the ordered case with lv_niovecs == 0 as part of > the natural loop: > > for (lv = log_vector; lv; lv->lv_next) { > for (index = 0; index < lv->lv_niovecs; index++) { > struct xfs_log_iovec *reg = &lv->lv_iovecp[index]; > struct xlog_op_header *ophdr = reg->i_addr; > > ASSERT(reg->i_len % sizeof(int32_t) == 0); > ASSERT((unsigned long)ptr % sizeof(int32_t) == 0); > > ophdr->oh_tid = cpu_to_be32(ticket->t_tid); > ophdr->oh_len = cpu_to_be32(reg->i_len - > sizeof(struct xlog_op_header)); > memcpy(ptr, reg->i_addr, reg->i_len); > xlog_write_adv_cnt(&ptr, &len, &log_offset, reg->i_len); > record_cnt++; > } > } Yup, that is definitely an improvement. It wasnt' an option with the way the existing code nested, but this is much, much neater. Thanks! Cheers, Dave. -- Dave Chinner david@fromorbit.com