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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 33EF0C3A59F for ; Thu, 29 Aug 2019 08:45:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0C9D1233A1 for ; Thu, 29 Aug 2019 08:45:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726839AbfH2Ipe (ORCPT ); Thu, 29 Aug 2019 04:45:34 -0400 Received: from mail104.syd.optusnet.com.au ([211.29.132.246]:52217 "EHLO mail104.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726417AbfH2Ipe (ORCPT ); Thu, 29 Aug 2019 04:45:34 -0400 Received: from dread.disaster.area (pa49-181-255-194.pa.nsw.optusnet.com.au [49.181.255.194]) by mail104.syd.optusnet.com.au (Postfix) with ESMTPS id 78D0F43CEF5; Thu, 29 Aug 2019 18:45:32 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92) (envelope-from ) id 1i3G3e-0002I8-Ot; Thu, 29 Aug 2019 18:45:30 +1000 Date: Thu, 29 Aug 2019 18:45:30 +1000 From: Dave Chinner To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org Subject: Re: [PATCH 4/5] xfs: speed up directory bestfree block scanning Message-ID: <20190829084530.GP1119@dread.disaster.area> References: <20190829063042.22902-1-david@fromorbit.com> <20190829063042.22902-5-david@fromorbit.com> <20190829081822.GD18195@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190829081822.GD18195@infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.2 cv=P6RKvmIu c=1 sm=1 tr=0 a=YO9NNpcXwc8z/SaoS+iAiA==:117 a=YO9NNpcXwc8z/SaoS+iAiA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=FmdZ9Uzk2mMA:10 a=7-415B0cAAAA:8 a=8Y9nZHUPy7GPshHu2nAA:9 a=RQO7YIQPXt1mDet7:21 a=hoifpHtEMtUlgY3f:21 a=CjuIK1q_8ugA:10 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Thu, Aug 29, 2019 at 01:18:22AM -0700, Christoph Hellwig wrote: > On Thu, Aug 29, 2019 at 04:30:41PM +1000, Dave Chinner wrote: > > + bests = dp->d_ops->free_bests_p(free); > > + dp->d_ops->free_hdr_from_disk(&freehdr, free); > > if (findex >= 0) { > > /* caller already found the freespace for us. */ > > - bests = dp->d_ops->free_bests_p(free); > > - dp->d_ops->free_hdr_from_disk(&freehdr, free); > > - > > I don't see any way how this is needed or helpful with this patch, > we are just going to ovewrite bests and freehdr before even looking > at them if the branch is not taken. *nod* The change is not useful anymore as a result of folding in your previous suggestions. I'll revert it. > > ASSERT(findex < freehdr.nvalid); > > ASSERT(be16_to_cpu(bests[findex]) != NULLDATAOFF); > > ASSERT(be16_to_cpu(bests[findex]) >= length); > > dbno = freehdr.firstdb + findex; > > - goto out; > > + goto found_block; > > The label rename while more descriptive also seems entirely unrelated. That was one of your previous suggestions :) I'll push it back up one patch into the cleanup patch and leave this as an optimisation only patch. > > + findex = 0; > > + free = fbp->b_addr; > > bests = dp->d_ops->free_bests_p(free); > > dp->d_ops->free_hdr_from_disk(&freehdr, free); > > + > > + /* Scan the free entry array for a large enough free space. */ > > + do { > > + if (be16_to_cpu(bests[findex]) != NULLDATAOFF && > > + be16_to_cpu(bests[findex]) >= length) { > > + dbno = freehdr.firstdb + findex; > > + goto found_block; > > } > > + } while (++findex < freehdr.nvalid); > > Nit: wou;dn't this be better written as a for loop also taking the > initialization of findex into the loop? Agreed - the next patch does that with the reversal of the search order. The end result is what you're asking for, so I'll leave this alone for now.... > Otherwise this looks good. I always like it when a speedup removes > code.. I hadn't noticed that - I was more concerned with ending up with readable code :) Cheers, Dave. -- Dave Chinner david@fromorbit.com