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From: Bob Peterson <rpeterso@redhat.com>
To: cluster-devel.redhat.com
Subject: [Cluster-devel] [PATCH 2/2] gfs2: Fix lru_count going negative
Date: Thu, 31 Jan 2019 10:04:18 -0500 (EST)	[thread overview]
Message-ID: <359471440.68850881.1548947058822.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <1247235469.68837763.1548945397399.JavaMail.zimbra@redhat.com>

----- Original Message -----
> > +
> > +	if (!test_bit(GLF_LRU, &gl->gl_flags)) {
> > +		set_bit(GLF_LRU, &gl->gl_flags);
> >  		atomic_inc(&lru_count);
> > +	}
> 
> The above may be simplified to something like:
> +	if (!test_and_set_bit(GLF_LRU, &gl->gl_flags))
>  		atomic_inc(&lru_count);

Scratch that. Andreas says test_and_set_bit() and similar are much more
expensive cpu-wise, and we're already protected from races by the
lru_lock, so I guess the original is better after all.

Bob Peterson



  reply	other threads:[~2019-01-31 15:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-31 10:55 [Cluster-devel] [PATCH 0/2] GFS2 counting fixes Ross Lagerwall
2019-01-31 10:55 ` [Cluster-devel] [PATCH 1/2] gfs2: Fix occasional glock use-after-free Ross Lagerwall
2019-01-31 11:23   ` Steven Whitehouse
2019-01-31 14:40   ` Bob Peterson
2019-01-31 17:18   ` Andreas Gruenbacher
2019-02-01  9:23     ` Ross Lagerwall
2019-02-01 14:34       ` Bob Peterson
2019-02-01 14:51       ` Bob Peterson
2019-02-01 15:03       ` [Cluster-devel] [PATCH 1/2] gfs2: Fix occasional glock use-after-free (Another debug patch) Bob Peterson
2019-03-26 18:49     ` [Cluster-devel] [PATCH 1/2] gfs2: Fix occasional glock use-after-free Ross Lagerwall
2019-03-26 19:14       ` Bob Peterson
2019-04-01 22:59         ` Andreas Gruenbacher
2019-04-05 17:50           ` Andreas Gruenbacher
2019-04-09 15:36             ` Ross Lagerwall
2019-04-09 15:41               ` Andreas Gruenbacher
2019-01-31 10:55 ` [Cluster-devel] [PATCH 2/2] gfs2: Fix lru_count going negative Ross Lagerwall
2019-01-31 11:21   ` Steven Whitehouse
2019-01-31 14:36   ` Bob Peterson
2019-01-31 15:04     ` Bob Peterson [this message]
2019-01-31 15:23     ` Ross Lagerwall
2019-01-31 18:32   ` Andreas Gruenbacher

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