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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2D3C8C43461 for ; Fri, 4 Sep 2020 16:32:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECF7B2073B for ; Fri, 4 Sep 2020 16:32:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726127AbgIDQcj (ORCPT ); Fri, 4 Sep 2020 12:32:39 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:23379 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725966AbgIDQcj (ORCPT ); Fri, 4 Sep 2020 12:32:39 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-444-VWbfWaerNumMQAVaRi5ZWA-1; Fri, 04 Sep 2020 12:32:35 -0400 X-MC-Unique: VWbfWaerNumMQAVaRi5ZWA-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 65CF2393B1; Fri, 4 Sep 2020 16:32:34 +0000 (UTC) Received: from bfoster (ovpn-113-130.rdu2.redhat.com [10.10.113.130]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA1627E41B; Fri, 4 Sep 2020 16:32:31 +0000 (UTC) Date: Fri, 4 Sep 2020 12:32:29 -0400 From: Brian Foster To: Gao Xiang Cc: linux-xfs@vger.kernel.org, "Darrick J . Wong" Subject: Re: [PATCH v2 2/2] xfs: clean up calculation of LR header blocks Message-ID: <20200904163229.GH529978@bfoster> References: <20200904082516.31205-1-hsiangkao@redhat.com> <20200904082516.31205-3-hsiangkao@redhat.com> <20200904112548.GC529978@bfoster> <20200904125929.GB28752@xiangao.remote.csb> <20200904133721.GE529978@bfoster> <20200904150730.GB17378@xiangao.remote.csb> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200904150730.GB17378@xiangao.remote.csb> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Fri, Sep 04, 2020 at 11:07:30PM +0800, Gao Xiang wrote: > On Fri, Sep 04, 2020 at 09:37:21AM -0400, Brian Foster wrote: > > On Fri, Sep 04, 2020 at 08:59:29PM +0800, Gao Xiang wrote: > ... > > > Could you kindly give me some code flow on your preferred way about > > > this so I could update this patch proper (since we have a complex > > > case in xlog_do_recovery_pass(), I'm not sure how the unique helper > > > will be like because there are 3 cases below...) > > > > > > - for the first 2 cases, we already have rhead read in-memory, > > > so the logic is like: > > > .... > > > log_bread (somewhere in advance) > > > .... > > > > > > if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) { > > > ... > > > } else { > > > ... > > > } > > > (so I folded this two cases in xlog_logrec_hblks()) > > > > > > - for xlog_do_recovery_pass, it behaves like > > > if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) { > > > log_bread (another extra bread to get h_size for > > > allocated buffer and hblks). > > > > > > ... > > > } else { > > > ... > > > } > > > so in this case we don't have rhead until > > > xfs_sb_version_haslogv2(&log->l_mp->m_sb) is true... > > > > > > > I'm not sure I'm following the problem... > > > > The current patch makes the following change in xlog_do_recovery_pass(): > > > > @@ -3024,15 +3018,10 @@ xlog_do_recovery_pass( > > if (error) > > goto bread_err1; > > > > - if ((be32_to_cpu(rhead->h_version) & XLOG_VERSION_2) && > > - (h_size > XLOG_HEADER_CYCLE_SIZE)) { > > - hblks = h_size / XLOG_HEADER_CYCLE_SIZE; > > - if (h_size % XLOG_HEADER_CYCLE_SIZE) > > - hblks++; > > + hblks = xlog_logrecv2_hblks(rhead); > > + if (hblks != 1) { > > kmem_free(hbp); > > hbp = xlog_alloc_buffer(log, hblks); > > - } else { > > - hblks = 1; > > } > > } else { > > ASSERT(log->l_sectBBsize == 1); > > > > My question is: why can't we replace the xlog_logrecv2_hblks() call here > > with xlog_logrec_hblks()? We already have rhead as the existing code is > > already looking at h_version. We're inside a _haslogv2() branch, so the > > check inside the helper is effectively a duplicate/no-op.. Hm? > > Yeah, I get your point. That would introduce a duplicated check of > _haslogv2() if we use xlog_logrec_hblks() here (IMHO compliers wouldn't > treat the 2nd _haslogv2() check as no-op). > Yeah, I meant it as more as a logical no-op. IOW, it wouldn't affect functionality. The check instructions might be duplicated, but I doubt that would measurably impact log recovery. > I will go forward like this if no other concerns. Thank you! > Thanks. Brian > Thanks, > Gao Xiang > > > > > Brian > > > > > Thanks in advance! > > > > > > Thanks, > > > Gao Xiang > > > > > > > > > > > > > > Brian > > > > > >