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Subject: Re: [Ocfs2-devel] [PATCH V3 2/2] ocfs2: add locking filter debugfs
 file
To:     Gang He <ghe@suse.com>
Cc:     mark@fasheh.com, jlbec@evilplan.org, jiangqi903@gmail.com,
        linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com
References: <20190523104047.14794-1-ghe@suse.com>
 <20190523104047.14794-2-ghe@suse.com>
From:   Wengang <wen.gang.wang@oracle.com>
Message-ID: <da93442d-3333-5bd6-ce0a-edb66a58109d@oracle.com>
Date:   Thu, 23 May 2019 09:43:58 -0700
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Hi Gang,

Could you paste an example of outputs before patch VS that after patch?
I think that would directly show what the patch does.

thanks,
wengang

On 05/23/2019 03:40 AM, Gang He wrote:
> Add locking filter debugfs file, which is used to filter lock
> resources dump from locking_state debugfs file.
> We use d_filter_secs field to filter lock resources dump,
> the default d_filter_secs(0) value filters nothing,
> otherwise, only dump the last N seconds active lock resources.
> This enhancement can avoid dumping lots of old records.
> The d_filter_secs value can be changed via locking_filter file.
>
> Compared with v2, ocfs2_dlm_init_debug() returns directly with
> error when creating locking filter debugfs file is failed, since
> ocfs2_dlm_shutdown_debug() will handle this failure perfectly.
> Compared with v1, the main change is to add CONFIG_OCFS2_FS_STATS
> macro definition judgment.
>
> Signed-off-by: Gang He <ghe@suse.com>
> Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
> ---
>   fs/ocfs2/dlmglue.c | 36 ++++++++++++++++++++++++++++++++++++
>   fs/ocfs2/ocfs2.h   |  2 ++
>   2 files changed, 38 insertions(+)
>
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index dccf4136f8c1..fbe4562cf4fe 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -3006,6 +3006,8 @@ struct ocfs2_dlm_debug *ocfs2_new_dlm_debug(void)
>   	kref_init(&dlm_debug->d_refcnt);
>   	INIT_LIST_HEAD(&dlm_debug->d_lockres_tracking);
>   	dlm_debug->d_locking_state = NULL;
> +	dlm_debug->d_locking_filter = NULL;
> +	dlm_debug->d_filter_secs = 0;
>   out:
>   	return dlm_debug;
>   }
> @@ -3104,11 +3106,33 @@ static int ocfs2_dlm_seq_show(struct seq_file *m, void *v)
>   {
>   	int i;
>   	char *lvb;
> +	u32 now, last = 0;
>   	struct ocfs2_lock_res *lockres = v;
> +	struct ocfs2_dlm_debug *dlm_debug =
> +			((struct ocfs2_dlm_seq_priv *)m->private)->p_dlm_debug;
>   
>   	if (!lockres)
>   		return -EINVAL;
>   
> +	if (dlm_debug->d_filter_secs) {
> +		now = ktime_to_timespec(ktime_get()).tv_sec;
> +#ifdef CONFIG_OCFS2_FS_STATS
> +		if (lockres->l_lock_prmode.ls_last >
> +		    lockres->l_lock_exmode.ls_last)
> +			last = lockres->l_lock_prmode.ls_last;
> +		else
> +			last = lockres->l_lock_exmode.ls_last;
> +#endif
> +		/*
> +		 * Use d_filter_secs field to filter lock resources dump,
> +		 * the default d_filter_secs(0) value filters nothing,
> +		 * otherwise, only dump the last N seconds active lock
> +		 * resources.
> +		 */
> +		if ((now - last) > dlm_debug->d_filter_secs)
> +			return 0;
> +	}
> +
>   	seq_printf(m, "0x%x\t", OCFS2_DLM_DEBUG_STR_VERSION);
>   
>   	if (lockres->l_type == OCFS2_LOCK_TYPE_DENTRY)
> @@ -3258,6 +3282,17 @@ static int ocfs2_dlm_init_debug(struct ocfs2_super *osb)
>   		goto out;
>   	}
>   
> +	dlm_debug->d_locking_filter = debugfs_create_u32("locking_filter",
> +						0600,
> +						osb->osb_debug_root,
> +						&dlm_debug->d_filter_secs);
> +	if (!dlm_debug->d_locking_filter) {
> +		ret = -EINVAL;
> +		mlog(ML_ERROR,
> +		     "Unable to create locking filter debugfs file.\n");
> +		goto out;
> +	}
> +
>   	ocfs2_get_dlm_debug(dlm_debug);
>   out:
>   	return ret;
> @@ -3269,6 +3304,7 @@ static void ocfs2_dlm_shutdown_debug(struct ocfs2_super *osb)
>   
>   	if (dlm_debug) {
>   		debugfs_remove(dlm_debug->d_locking_state);
> +		debugfs_remove(dlm_debug->d_locking_filter);
>   		ocfs2_put_dlm_debug(dlm_debug);
>   	}
>   }
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index 8efa022684f4..f4da51099889 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -237,6 +237,8 @@ struct ocfs2_orphan_scan {
>   struct ocfs2_dlm_debug {
>   	struct kref d_refcnt;
>   	struct dentry *d_locking_state;
> +	struct dentry *d_locking_filter;
> +	u32 d_filter_secs;
>   	struct list_head d_lockres_tracking;
>   };
>