linux-kernel - Re: Re: [PATCH] RDMA/siw: Print error code while kthread

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Date:   Wed, 10 Jul 2019 08:38:00 +0000
From:   "Bernard Metzler" <BMT@...ich.ibm.com>
To:     "Leon Romanovsky" <leon@...nel.org>
Cc:     "YueHaibing" <yuehaibing@...wei.com>, dledford@...hat.com,
        jgg@...pe.ca, linux-kernel@...r.kernel.org,
        linux-rdma@...r.kernel.org
Subject: Re:  Re: [PATCH] RDMA/siw: Print error code while kthread_create failed

-----"Leon Romanovsky" <leon@...nel.org> wrote: -----

>To: "YueHaibing" <yuehaibing@...wei.com>
>From: "Leon Romanovsky" <leon@...nel.org>
>Date: 07/10/2019 06:36AM
>Cc: bmt@...ich.ibm.com, dledford@...hat.com, jgg@...pe.ca,
>linux-kernel@...r.kernel.org, linux-rdma@...r.kernel.org
>Subject: [EXTERNAL] Re: [PATCH] RDMA/siw: Print error code while
>kthread_create failed
>
>On Wed, Jul 10, 2019 at 09:50:09AM +0800, YueHaibing wrote:
>> In iw_create_tx_threads(), if we failed to create kthread,
>> we should print the 'rv', this fix gcc warning:
>>
>> drivers/infiniband/sw/siw/siw_main.c: In function
>'siw_create_tx_threads':
>> drivers/infiniband/sw/siw/siw_main.c:91:11: warning:
>>  variable 'rv' set but not used [-Wunused-but-set-variable]
>>
>> Reported-by: Hulk Robot <hulkci@...wei.com>
>> Signed-off-by: YueHaibing <yuehaibing@...wei.com>
>> ---
>>  drivers/infiniband/sw/siw/siw_main.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/infiniband/sw/siw/siw_main.c
>b/drivers/infiniband/sw/siw/siw_main.c
>> index fd2552a..2a70830d 100644
>> --- a/drivers/infiniband/sw/siw/siw_main.c
>> +++ b/drivers/infiniband/sw/siw/siw_main.c
>> @@ -101,7 +101,8 @@ static int siw_create_tx_threads(void)
>>  		if (IS_ERR(siw_tx_thread[cpu])) {
>>  			rv = PTR_ERR(siw_tx_thread[cpu]);
>>  			siw_tx_thread[cpu] = NULL;
>> -			pr_info("Creating TX thread for CPU %d failed", cpu);
>> +			pr_info("Creating TX thread for CPU%d failed %d\n",
>> +				cpu, rv);
>
>Delete this print together with variable, failure to create kthread
>is basic failure, which affect performance only. The whole kthread
>creation spam in this driver looked suspicious during submission
>and it continues to be.
>
>Thanks

Right, I agree with Leon. Better remove all those printouts. We
already have a warning if we cannot start any thread. Also
stopping those threads is not worth spamming the console. I just
forgot to remove after Leon's comment. Would it be possible
to apply the following?

Thanks a lot!
Bernard.

>From e4ca3d4dec86bb5731f8e3cb0cdd01e84b315d80 Mon Sep 17 00:00:00 2001
From: Bernard Metzler <bmt@...ich.ibm.com>
Date: Wed, 10 Jul 2019 10:03:17 +0200
Subject: [PATCH] remove kthread create/destroy printouts

Signed-off-by: Bernard Metzler <bmt@...ich.ibm.com>
---
 drivers/infiniband/sw/siw/siw_main.c  | 4 +---
 drivers/infiniband/sw/siw/siw_qp_tx.c | 4 ----
 2 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/infiniband/sw/siw/siw_main.c b/drivers/infiniband/sw/siw/siw_main.c
index fd2552a9091d..f55c4e80aea4 100644
--- a/drivers/infiniband/sw/siw/siw_main.c
+++ b/drivers/infiniband/sw/siw/siw_main.c
@@ -88,7 +88,7 @@ static void siw_device_cleanup(struct ib_device *base_dev)
 
 static int siw_create_tx_threads(void)
 {
-	int cpu, rv, assigned = 0;
+	int cpu, assigned = 0;
 
 	for_each_online_cpu(cpu) {
 		/* Skip HT cores */
@@ -99,9 +99,7 @@ static int siw_create_tx_threads(void)
 			kthread_create(siw_run_sq, (unsigned long *)(long)cpu,
 				       "siw_tx/%d", cpu);
 		if (IS_ERR(siw_tx_thread[cpu])) {
-			rv = PTR_ERR(siw_tx_thread[cpu]);
 			siw_tx_thread[cpu] = NULL;
-			pr_info("Creating TX thread for CPU %d failed", cpu);
 			continue;
 		}
 		kthread_bind(siw_tx_thread[cpu], cpu);
diff --git a/drivers/infiniband/sw/siw/siw_qp_tx.c b/drivers/infiniband/sw/siw/siw_qp_tx.c
index 2c3d250ee57c..fff02b56d38a 100644
--- a/drivers/infiniband/sw/siw/siw_qp_tx.c
+++ b/drivers/infiniband/sw/siw/siw_qp_tx.c
@@ -1200,8 +1200,6 @@ int siw_run_sq(void *data)
 	init_llist_head(&tx_task->active);
 	init_waitqueue_head(&tx_task->waiting);
 
-	pr_info("Started siw TX thread on CPU %u\n", nr_cpu);
-
 	while (1) {
 		struct llist_node *fifo_list = NULL;
 
@@ -1239,8 +1237,6 @@ int siw_run_sq(void *data)
 			siw_sq_resume(qp);
 		}
 	}
-	pr_info("Stopped siw TX thread on CPU %u\n", nr_cpu);
-
 	return 0;
 }
 
-- 
2.17.2