From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Whitehouse Date: Fri, 10 Aug 2018 13:21:28 +0100 Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Simplify iterative add loop in foreach_descriptor In-Reply-To: References: <183182471.770089.1533754323408.JavaMail.zimbra@redhat.com> <2e040139-cc86-3256-884e-8e52e48e6df7@redhat.com> Message-ID: <4848596d-dbcd-6208-8349-4df7eb7a042b@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, On 10/08/18 13:13, Andreas Gruenbacher wrote: > On 9 August 2018 at 11:35, Steven Whitehouse wrote: >> Hi, >> >> >> >> On 08/08/18 19:52, Bob Peterson wrote: >>> Hi, >>> >>> Before this patch, function foreach_descriptor repeatedly called >>> function gfs2_replay_incr_blk which just incremented the value while >>> decrementing another, and checked for wrap. This is a waste of time. >>> This patch just adds the value and adjusts it if a wrap occurred. >>> >>> Signed-off-by: Bob Peterson >>> --- >>> fs/gfs2/recovery.c | 5 +++-- >>> 1 file changed, 3 insertions(+), 2 deletions(-) >>> >>> diff --git a/fs/gfs2/recovery.c b/fs/gfs2/recovery.c >>> index 0f501f938d1c..6c6b19263b82 100644 >>> --- a/fs/gfs2/recovery.c >>> +++ b/fs/gfs2/recovery.c >>> @@ -354,8 +354,9 @@ static int foreach_descriptor(struct gfs2_jdesc *jd, >>> unsigned int start, >>> return error; >>> } >>> - while (length--) >>> - gfs2_replay_incr_blk(jd, &start); >>> + start += length; >>> + if (start >= jd->jd_blocks) >>> + start -= jd->jd_blocks; >>> brelse(bh); >>> } >>> >> Now you've hidden the increment of the replay block. Please don't open code >> this, but just add an argument to gfs2_replay_incr_blk() such that you can >> tell it how many blocks to increment, rather than just assuming a single >> block as it does at the moment. Otherwise this can easily get missed when >> someone looks at the code in future, and expects gfs2_replay_incr_blk to be >> the only thing that changes the position during recovery, > If we really want to encapsulate "add modulo jd->jd_blocks", it's also > open-coded in find_good_lh and jhead_scan. > > Andreas I wonder if those will go away with Abhi's patch set in due course? Steve.