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

[Junxiao Bi <junxiao.bi@oracle.com>]

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.

> +	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?

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;
>