Re: [PATCH V2 2/2] ocfs2: add locking filter debugfs file

[Gang He]

Hello Guys,

If you have time, please help to review these two patches.
The patch logic is very simple, but it can help us to control lock resource dump length.
In product environment, there are lots of lock resources in memory as time goes by.


Thanks
Gang

>>> On 2019/4/29 at 16:33, in message <20190429083353.1410-1-ghe@xxxxxxxx>, Gang He
<ghe@xxxxxxxx> 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 v1, the main change is to add CONFIG_OCFS2_FS_STATS
> macro definition judgment.
> 
> Signed-off-by: Gang He <ghe@xxxxxxxx>
> ---
>  fs/ocfs2/dlmglue.c | 38 ++++++++++++++++++++++++++++++++++++++
>  fs/ocfs2/ocfs2.h   |  2 ++
>  2 files changed, 40 insertions(+)
> 
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index dccf4136f8c1..554d37d52510 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 +3282,19 @@ 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");
> +		debugfs_remove(dlm_debug->d_locking_state);
> +		dlm_debug->d_locking_state = NULL;
> +		goto out;
> +	}
> +
>  	ocfs2_get_dlm_debug(dlm_debug);
>  out:
>  	return ret;
> @@ -3269,6 +3306,7 @@ 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;
>  };
>  
> -- 
> 2.21.0