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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, TVD_PH_BODY_ACCOUNTS_PRE,URIBL_BLOCKED autolearn=ham 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 A97FBC43331 for ; Wed, 25 Mar 2020 12:33:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7EBAA2076A for ; Wed, 25 Mar 2020 12:33:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cGe4Vcc4" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726700AbgCYMdX (ORCPT ); Wed, 25 Mar 2020 08:33:23 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:43870 "EHLO us-smtp-delivery-74.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727177AbgCYMdX (ORCPT ); Wed, 25 Mar 2020 08:33:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585139601; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=7e30IcRwkpFDSKRLUrKT2Gv7ZjOigwgrZRbkLiN5fQE=; b=cGe4Vcc48aTMKMOo5kiF6BH51JyuwFiphP5G1YMnOLQE8riI2swCTlaEMcBIMZ3y/eyL2f 4Yoev1jL+Ru2ZYfHTHlvbUIR7U8JJxoX8z9wU1L+YIOwQi16lKjK6ojMYVwLcXQy85gRSj iUm1Oo2UtcOkqG0OP3vjOOwkUASaWUk= 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-286-yK60_9orOvqG9rJY29AQJw-1; Wed, 25 Mar 2020 08:33:18 -0400 X-MC-Unique: yK60_9orOvqG9rJY29AQJw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2C116107ACC4; Wed, 25 Mar 2020 12:33:17 +0000 (UTC) Received: from bfoster (dhcp-41-2.bos.redhat.com [10.18.41.2]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A4BB010002AE; Wed, 25 Mar 2020 12:33:16 +0000 (UTC) Date: Wed, 25 Mar 2020 08:33:14 -0400 From: Brian Foster To: Christoph Hellwig Cc: linux-xfs@vger.kernel.org, david@fromorbit.com, Dave Chinner Subject: Re: [PATCH 1/8] xfs: don't try to write a start record into every iclog Message-ID: <20200325123314.GC10922@bfoster> References: <20200324174459.770999-1-hch@lst.de> <20200324174459.770999-2-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200324174459.770999-2-hch@lst.de> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org On Tue, Mar 24, 2020 at 06:44:52PM +0100, Christoph Hellwig wrote: > From: Dave Chinner > > The xlog_write() function iterates over iclogs until it completes > writing all the log vectors passed in. The ticket tracks whether > a start record has been written or not, so only the first iclog gets > a start record. We only ever pass single use tickets to > xlog_write() so we only ever need to write a start record once per > xlog_write() call. > > Hence we don't need to store whether we should write a start record > in the ticket as the callers provide all the information we need to > determine if a start record should be written. For the moment, we > have to ensure that we clear the XLOG_TIC_INITED appropriately so > the code in xfs_log_done() still works correctly for committing > transactions. > > Signed-off-by: Dave Chinner > [hch: use an need_start_rec bool] > Signed-off-by: Christoph Hellwig > --- > fs/xfs/xfs_log.c | 63 ++++++++++++++++++++++++------------------------ > 1 file changed, 32 insertions(+), 31 deletions(-) > > diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c > index 2a90a483c2d6..bf071552094a 100644 > --- a/fs/xfs/xfs_log.c > +++ b/fs/xfs/xfs_log.c ... > @@ -2372,25 +2359,29 @@ xlog_write( > int record_cnt = 0; > int data_cnt = 0; > int error = 0; > + bool need_start_rec = true; > > *start_lsn = 0; > > - len = xlog_write_calc_vec_length(ticket, log_vector); > > /* > * Region headers and bytes are already accounted for. > * We only need to take into account start records and > * split regions in this function. > */ > - if (ticket->t_flags & XLOG_TIC_INITED) > - ticket->t_curr_res -= sizeof(xlog_op_header_t); > + if (ticket->t_flags & XLOG_TIC_INITED) { > + ticket->t_curr_res -= sizeof(struct xlog_op_header); > + ticket->t_flags &= ~XLOG_TIC_INITED; > + } > > /* > * Commit record headers need to be accounted for. These > * come in as separate writes so are easy to detect. > */ > - if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS)) > - ticket->t_curr_res -= sizeof(xlog_op_header_t); > + if (flags & (XLOG_COMMIT_TRANS | XLOG_UNMOUNT_TRANS)) { > + ticket->t_curr_res -= sizeof(struct xlog_op_header); > + need_start_rec = false; > + } Hmm.. I was asking for a comment update in v1 for this logic change. Looking through it again, what happens here if xfs_log_write_unmount_record() clears the UNMOUNT_TRANS flag for that summary counter check? That looks like a potential behavior change wrt to the start record.. Brian > > if (ticket->t_curr_res < 0) { > xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, > @@ -2399,6 +2390,8 @@ xlog_write( > xfs_force_shutdown(log->l_mp, SHUTDOWN_LOG_IO_ERROR); > } > > + len = xlog_write_calc_vec_length(ticket, log_vector, need_start_rec); > + > index = 0; > lv = log_vector; > vecp = lv->lv_iovecp; > @@ -2425,7 +2418,6 @@ xlog_write( > while (lv && (!lv->lv_niovecs || index < lv->lv_niovecs)) { > struct xfs_log_iovec *reg; > struct xlog_op_header *ophdr; > - int start_rec_copy; > int copy_len; > int copy_off; > bool ordered = false; > @@ -2441,11 +2433,15 @@ xlog_write( > ASSERT(reg->i_len % sizeof(int32_t) == 0); > ASSERT((unsigned long)ptr % sizeof(int32_t) == 0); > > - start_rec_copy = xlog_write_start_rec(ptr, ticket); > - if (start_rec_copy) { > - record_cnt++; > + /* > + * Before we start formatting log vectors, we need to > + * write a start record. Only do this for the first > + * iclog we write to. > + */ > + if (need_start_rec) { > + xlog_write_start_rec(ptr, ticket); > xlog_write_adv_cnt(&ptr, &len, &log_offset, > - start_rec_copy); > + sizeof(struct xlog_op_header)); > } > > ophdr = xlog_write_setup_ophdr(log, ptr, ticket, flags); > @@ -2477,8 +2473,13 @@ xlog_write( > xlog_write_adv_cnt(&ptr, &len, &log_offset, > copy_len); > } > - copy_len += start_rec_copy + sizeof(xlog_op_header_t); > + copy_len += sizeof(struct xlog_op_header); > record_cnt++; > + if (need_start_rec) { > + copy_len += sizeof(struct xlog_op_header); > + record_cnt++; > + need_start_rec = false; > + } > data_cnt += contwr ? copy_len : 0; > > error = xlog_write_copy_finish(log, iclog, flags, > -- > 2.25.1 >