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

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Date:   Sun, 05 May 2019 02:53:57 -0600
From:   "Gang He" <ghe@...e.com>
To:     <jlbec@...lplan.org>, <mark@...heh.com>, <jiangqi903@...il.com>
Cc:     <akpm@...ux-foundation.org>, <ocfs2-devel@....oracle.com>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2 2/2] ocfs2: add locking filter debugfs file



>>> On 2019/5/5 at 14:54, in message
<f65e80e4-c99c-c84f-30c1-65991aec4da7@...il.com>, Joseph Qi
<jiangqi903@...il.com> wrote:
> Hi Gang,
> 
> On 19/4/29 16:33, 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 v1, the main change is to add CONFIG_OCFS2_FS_STATS
>> macro definition judgment.
>> 
>> Signed-off-by: Gang He <ghe@...e.com>
>> ---
>>  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;
> 
> Or we can just leave this cleanup for ocfs2_dlm_shutdown_debug()?
Yes, it looks more concise to delete these two lines code, then let ocfs2_dlm_shutdown_debug()
function to handle the cleanup in case failure.

Thanks
Gang

> 
> Thanks,
> Joseph
> 
>> +		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;
>>  };
>>  
>>