[Ocfs2-devel] [PATCH] ocfs2: add uuid to ocfs2 thread name for problem analysis

[Joseph Qi <joseph.qi@huawei.com>]

Hi Junxiao,

On 2015/10/27 15:56, Junxiao Bi wrote:
> Hi Joseph,
> 
> See comments below.
> 
> On 10/27/2015 11:32 AM, Joseph Qi wrote:
>> A node can mount multiple ocfs2 volumes. And if thread names are same
>> for each volume/domain, it will bring inconvenience when analyzing
>> problems because we have to identify which volume/domain the messages
>> belong to.
>> Since thread name will be printed to messages, so add volume uuid or dlm
>> name to thread name (like o2hb thread) can benefit problem analysis.
>>
>> Signed-off-by: Joseph Qi <joseph.qi@huawei.com>
>> ---
>>  fs/ocfs2/dlm/dlmdomain.c   | 5 ++++-
>>  fs/ocfs2/dlm/dlmrecovery.c | 2 +-
>>  fs/ocfs2/dlm/dlmthread.c   | 3 ++-
>>  fs/ocfs2/dlmglue.c         | 3 ++-
>>  fs/ocfs2/journal.c         | 4 ++--
>>  5 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/ocfs2/dlm/dlmdomain.c b/fs/ocfs2/dlm/dlmdomain.c
>> index 7df88a6..9416124 100644
>> --- a/fs/ocfs2/dlm/dlmdomain.c
>> +++ b/fs/ocfs2/dlm/dlmdomain.c
>> @@ -1860,6 +1860,7 @@ static int dlm_join_domain(struct dlm_ctxt *dlm)
>>  	int status;
>>  	unsigned int backoff;
>>  	unsigned int total_backoff = 0;
>> +	char wq_name[O2NM_MAX_NAME_LEN];
>>
>>  	BUG_ON(!dlm);
>>
>> @@ -1889,7 +1890,9 @@ static int dlm_join_domain(struct dlm_ctxt *dlm)
>>  		goto bail;
>>  	}
>>
>> -	dlm->dlm_worker = create_singlethread_workqueue("dlm_wq");
>> +	memset(wq_name, 0, O2NM_MAX_NAME_LEN);
> I didn't see memset need here.
> 
I will remove it since snprintf will include the trailing null byte.

>> +	snprintf(wq_name, O2NM_MAX_NAME_LEN, "dlm_wq-%s", dlm->name);
>> +	dlm->dlm_worker = create_singlethread_workqueue(wq_name);
>>  	if (!dlm->dlm_worker) {
>>  		status = -ENOMEM;
>>  		mlog_errno(status);
>> diff --git a/fs/ocfs2/dlm/dlmrecovery.c b/fs/ocfs2/dlm/dlmrecovery.c
>> index a43f9ef..570509e 100644
>> --- a/fs/ocfs2/dlm/dlmrecovery.c
>> +++ b/fs/ocfs2/dlm/dlmrecovery.c
>> @@ -205,7 +205,7 @@ int dlm_launch_recovery_thread(struct dlm_ctxt *dlm)
>>  	mlog(0, "starting dlm recovery thread...\n");
>>
>>  	dlm->dlm_reco_thread_task = kthread_run(dlm_recovery_thread, dlm,
>> -						"dlm_reco_thread");
>> +			"dlm_reco_thread-%s", dlm->name);
> Indeed max length of task name is 16 bytes, and "dlm_reco_thread" plus
> '\0' have taken all the space. So indeed above code is useless. Can we
> rename this name and maybe other one(like "dlm_thread") to leave more
> space for domain marker?
> 
Yes, you are right. For dlm_reco_thread it won't print any uuid bytes.
I put it here just for code consistency.
It is really hard for me to rename it to a better one:)
Any suggestions?

Thanks,
Joseph

> Thanks,
> Junxiao.
> 
>>  	if (IS_ERR(dlm->dlm_reco_thread_task)) {
>>  		mlog_errno(PTR_ERR(dlm->dlm_reco_thread_task));
>>  		dlm->dlm_reco_thread_task = NULL;
>> diff --git a/fs/ocfs2/dlm/dlmthread.c b/fs/ocfs2/dlm/dlmthread.c
>> index 69aac6f..e2bd691 100644
>> --- a/fs/ocfs2/dlm/dlmthread.c
>> +++ b/fs/ocfs2/dlm/dlmthread.c
>> @@ -483,7 +483,8 @@ int dlm_launch_thread(struct dlm_ctxt *dlm)
>>  {
>>  	mlog(0, "Starting dlm_thread...\n");
>>
>> -	dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread");
>> +	dlm->dlm_thread_task = kthread_run(dlm_thread, dlm, "dlm_thread-%s",
>> +			dlm->name);
>>  	if (IS_ERR(dlm->dlm_thread_task)) {
>>  		mlog_errno(PTR_ERR(dlm->dlm_thread_task));
>>  		dlm->dlm_thread_task = NULL;
>> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
>> index 23157e4..fd4f536 100644
>> --- a/fs/ocfs2/dlmglue.c
>> +++ b/fs/ocfs2/dlmglue.c
>> @@ -2998,7 +2998,8 @@ int ocfs2_dlm_init(struct ocfs2_super *osb)
>>  	}
>>
>>  	/* launch downconvert thread */
>> -	osb->dc_task = kthread_run(ocfs2_downconvert_thread, osb, "ocfs2dc");
>> +	osb->dc_task = kthread_run(ocfs2_downconvert_thread, osb, "ocfs2dc-%s",
>> +			osb->uuid_str);
>>  	if (IS_ERR(osb->dc_task)) {
>>  		status = PTR_ERR(osb->dc_task);
>>  		osb->dc_task = NULL;
>> diff --git a/fs/ocfs2/journal.c b/fs/ocfs2/journal.c
>> index 627d88c..86b9a93 100644
>> --- a/fs/ocfs2/journal.c
>> +++ b/fs/ocfs2/journal.c
>> @@ -1074,7 +1074,7 @@ int ocfs2_journal_load(struct ocfs2_journal *journal, int local, int replayed)
>>  	/* Launch the commit thread */
>>  	if (!local) {
>>  		osb->commit_task = kthread_run(ocfs2_commit_thread, osb,
>> -					       "ocfs2cmt");
>> +				"ocfs2cmt-%s", osb->uuid_str);
>>  		if (IS_ERR(osb->commit_task)) {
>>  			status = PTR_ERR(osb->commit_task);
>>  			osb->commit_task = NULL;
>> @@ -1491,7 +1491,7 @@ void ocfs2_recovery_thread(struct ocfs2_super *osb, int node_num)
>>  		goto out;
>>
>>  	osb->recovery_thread_task =  kthread_run(__ocfs2_recovery_thread, osb,
>> -						 "ocfs2rec");
>> +			"ocfs2rec-%s", osb->uuid_str);
>>  	if (IS_ERR(osb->recovery_thread_task)) {
>>  		mlog_errno((int)PTR_ERR(osb->recovery_thread_task));
>>  		osb->recovery_thread_task = NULL;
>>
> 
> 
> .
>