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=-15.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 C7709C433B4 for ; Fri, 23 Apr 2021 11:07:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 891EC61468 for ; Fri, 23 Apr 2021 11:07:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229890AbhDWLH7 (ORCPT ); Fri, 23 Apr 2021 07:07:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:54826 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229871AbhDWLH6 (ORCPT ); Fri, 23 Apr 2021 07:07:58 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619176042; 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=2V5/qg/7b2mzgwegTNNBzQJGdexDyvvKIyI/glg1eog=; b=OUrVqKvlSuQ58W/1rTomGvf63J9+jXO4SnE+4JuDW1Z6R29TqL6c1PPMjDWrn1gf8WGRyQ WDD+Bp0ZhEar9zM5Xm1CTpq4hsHSxxWSJML6Ea4b2TgNZ7eFg/Kb/9lKOqL8HlbWucmuS6 PgnMbnod7H/UEvZOwvpJTevu/wgn14I= 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-252-r3v6AYx-PJeYbjd5mU2XYw-1; Fri, 23 Apr 2021 07:07:20 -0400 X-MC-Unique: r3v6AYx-PJeYbjd5mU2XYw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B3B7218B9F49 for ; Fri, 23 Apr 2021 11:07:19 +0000 (UTC) Received: from bfoster (ovpn-112-25.rdu2.redhat.com [10.10.112.25]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 29A0A19D9B; Fri, 23 Apr 2021 11:07:19 +0000 (UTC) Date: Fri, 23 Apr 2021 07:07:17 -0400 From: Brian Foster To: bxue@redhat.com Cc: fstests@vger.kernel.org, minlei@redhat.com, lczerner@redhat.com Subject: Re: [PATCH v2] generic/563: tolerate small reads in "write -> read/write" sub-test Message-ID: References: <20210422153147.1049666-1-bxue@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210422153147.1049666-1-bxue@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: fstests@vger.kernel.org On Thu, Apr 22, 2021 at 11:31:47PM +0800, bxue@redhat.com wrote: > From: Boyang Xue > > On ext2/ext3, it's expected that several single block metadata reads can occur > when writing to file in the same cgroup (the stack is like below[1]). The > purpose of the "write -> read/write" subtest is to make sure the larger pwrite > is accounted to the correct cgroup, not necessarily enforce that zero bytes are > read in service of the write. This patch fixes the sub-test in order to tolerate > small reads in 1st cgroup. > > [1] Callchain of the read: > > @ext3_read_bio[ > submit_bio+1 > submit_bh_wbc+365 > ext4_read_bh+72 > ext4_get_branch+201 > ext4_ind_map_blocks+382 > ext4_map_blocks+295 > _ext4_get_block+170 > __block_write_begin_int+328 > ext4_write_begin+541 > generic_perform_write+213 > ext4_buffered_write_iter+167 > new_sync_write+345 > vfs_write+438 > __x64_sys_pwrite64+140 > do_syscall_64+51 > entry_SYSCALL_64_after_hwframe+68 > , 5793, 12]: 3 > > Signed-off-by: Boyang Xue > --- > Hi, > > This patch fix the "write -> read/write" sub-test in order to tolerate > small reads in service of the write (like read metadata). > > Change from v1: > (1) More details in commit log, including example call stack > (2) Set the fixed tolerance value to 33792 for accuracy > (3) Update percentage tolerance value to fixed value 0, where doesn't > fail the test > > Tested pass on ext2/ext3/ext4 x 1k/2k/4k blksize. > > Thanks, > Boyang > > tests/generic/563 | 20 +++++++++++++------- > 1 file changed, 13 insertions(+), 7 deletions(-) > > diff --git a/tests/generic/563 b/tests/generic/563 > index b113eacf..44394b4b 100755 > --- a/tests/generic/563 > +++ b/tests/generic/563 > @@ -60,6 +60,8 @@ check_cg() > cgname=$(basename $cgroot) > expectedread=$2 > expectedwrite=$3 > + readtol=$4 > + writetol=$5 > rbytes=0 > wbytes=0 > > @@ -71,8 +73,8 @@ check_cg() > awk -F = '{ print $2 }'` > fi > > - _within_tolerance "read" $rbytes $expectedread 5% -v > - _within_tolerance "write" $wbytes $expectedwrite 5% -v > + _within_tolerance "read" $rbytes $expectedread $readtol -v > + _within_tolerance "write" $wbytes $expectedwrite $writetol -v > } > > # Move current process to another cgroup. > @@ -113,7 +115,7 @@ $XFS_IO_PROG -c "pread 0 $iosize" -c "pwrite 0 $iosize" -c fsync \ > $SCRATCH_MNT/file >> $seqres.full 2>&1 > switch_cg $cgdir > $XFS_IO_PROG -c fsync $SCRATCH_MNT/file > -check_cg $cgdir/$seq-cg $iosize $iosize > +check_cg $cgdir/$seq-cg $iosize $iosize 5% 5% > > # Write from one cgroup then read and write from a second. Writes are charged to > # the first group and nothing to the second. > @@ -126,8 +128,12 @@ $XFS_IO_PROG -c "pread 0 $iosize" -c "pwrite 0 $iosize" $SCRATCH_MNT/file \ > >> $seqres.full 2>&1 > switch_cg $cgdir > $XFS_IO_PROG -c fsync $SCRATCH_MNT/file > -check_cg $cgdir/$seq-cg 0 $iosize > -check_cg $cgdir/$seq-cg-2 0 0 > +# Use a fixed value tolerance for the expected value of zero here > +# because filesystems might perform a small number of metadata reads to > +# complete the write. On ext2/3 with 1k block size, the read bytes is > +# as large as 33792. > +check_cg $cgdir/$seq-cg 0 $iosize 33792 0 Shouldn't that last parameter (write tolerance) remain as 5%? > +check_cg $cgdir/$seq-cg-2 0 0 0 0 > > # Read from one cgroup, read & write from a second. Both reads and writes are > # charged to the first group and nothing to the second. > @@ -140,8 +146,8 @@ $XFS_IO_PROG -c "pread 0 $iosize" -c "pwrite 0 $iosize" $SCRATCH_MNT/file \ > >> $seqres.full 2>&1 > switch_cg $cgdir > $XFS_IO_PROG -c fsync $SCRATCH_MNT/file > -check_cg $cgdir/$seq-cg $iosize $iosize > -check_cg $cgdir/$seq-cg-2 0 0 > +check_cg $cgdir/$seq-cg $iosize $iosize 5% 0 And here too? Otherwise the patch LGTM. Brian > +check_cg $cgdir/$seq-cg-2 0 0 0 0 > > echo "-io" > $cgdir/cgroup.subtree_control || _fail "subtree control" > > -- > 2.27.0 >