[Ocfs2-devel] [PATCH 2/3] ocfs2/cluster: Increase the live threshold

[Mark Fasheh <mfasheh@suse.com>]

The patch itself looks fine. Can I ask you to add more reasoning for the
change in the comment? Pretend that we're looking at that code in 2 years
scratching our heads going "why did this get changed"
	--Mark

On Tue, Apr 05, 2011 at 03:21:08PM -0700, Sunil Mushran wrote:
> Double the live threshold for the first region in the global heartbeat
> mode. The default, 2, is bare minimum. Increasing it will affect all
> mounts in the local heartbeat mode. Instead we increase it only for
> the global heartbeat mode and that too only the first region. This is
> only to increase the margin of safety.
> 
> Addresses internal Oracle bug#10635585.
> 
> Signed-off-by: Sunil Mushran <sunil.mushran@oracle.com>
> ---
>  fs/ocfs2/cluster/heartbeat.c |   13 ++++++++++++-
>  1 files changed, 12 insertions(+), 1 deletions(-)
> 
> diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
> index 2461eb3..ec50121 100644
> --- a/fs/ocfs2/cluster/heartbeat.c
> +++ b/fs/ocfs2/cluster/heartbeat.c
> @@ -1690,6 +1690,7 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
>  	struct file *filp = NULL;
>  	struct inode *inode = NULL;
>  	ssize_t ret = -EINVAL;
> +	int live_threshold;
>  
>  	if (reg->hr_bdev)
>  		goto out;
> @@ -1766,8 +1767,18 @@ static ssize_t o2hb_region_dev_write(struct o2hb_region *reg,
>  	 * A node is considered live after it has beat LIVE_THRESHOLD
>  	 * times.  We're not steady until we've given them a chance
>  	 * _after_ our first read.
> +	 * The default threshold is bare minimum so as to limit the delay
> +	 * during mounts. For global heartbeat, the threshold doubled for the
> +	 * first region.
>  	 */
> -	atomic_set(&reg->hr_steady_iterations, O2HB_LIVE_THRESHOLD + 1);
> +	live_threshold = O2HB_LIVE_THRESHOLD;
> +	if (o2hb_global_heartbeat_active()) {
> +		spin_lock(&o2hb_live_lock);
> +		if (o2hb_pop_count(&o2hb_region_bitmap, O2NM_MAX_REGIONS) == 1)
> +			live_threshold <<= 1;
> +		spin_unlock(&o2hb_live_lock);
> +	}
> +	atomic_set(&reg->hr_steady_iterations, live_threshold + 1);
>  
>  	hb_task = kthread_run(o2hb_thread, reg, "o2hb-%s",
>  			      reg->hr_item.ci_name);
> -- 
> 1.7.1
> 
> 
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--
Mark Fasheh