Re: [Ocfs2-devel] [PATCH V3 2/2] ocfs2: add locking filter debugfs file

[Wengang Wang]

Hi Gang,

OK, I was thinking you are dumping the new last access time field too.

thanks,
wengang

On 2019/5/23 19:15, Gang He wrote:
> Hello Wengang,
>
> This patch is used to add a filter attribute(the default value is 0), the kernel module can use this attribute value to filter the lock resources dumping.
> By default(the value is 0), the kernel module does not filter any lock resources dumping, the behavior is like before.
> If the user set a value(N) of this attribute, the kernel module will only dump the latest N seconds active lock resources, this will avoid dumping lots of inactive lock resources.
>
> Thanks
> Gang
>
> > > > On 2019/5/24 at 0:43, in message
> <da93442d-3333-5bd6-ce0a-edb66a58109d@xxxxxxxxxx>, Wengang
> <wen.gang.wang@xxxxxxxxxx> wrote:
> > 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@xxxxxxxx>
> > > Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
> > > ---
> > >    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;
> > >    };
> > >