There would be so many same lines printed by frequent printk if one
disk went wrong, like,
[ 546.185242] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185258] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185280] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185307] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185334] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185364] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185390] sd 0:1:0:0: rejecting I/O to offline device
[ 546.185410] sd 0:1:0:0: rejecting I/O to offline device
For slow serial console, the frequent printk may be blocked for a
long time, and if any spin_lock has been acquired before the printk
like in scsi_request_fn, watchdog could be triggered.
Related disscussion can be found here,
https://bugzilla.kernel.org/show_bug.cgi?id=199003
And Petr brought the idea to throttle the frequent printk, it's
useless to print the same lines frequently after all.
v2->v1: fix some typos
Suggested-by: Petr Mladek <[email protected]>
Suggested-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Wen Yang <[email protected]>
Signed-off-by: Jiang Biao <[email protected]>
Signed-off-by: Tan Hu <[email protected]>
CC: BartVanAssche <[email protected]>
CC: Petr Mladek <[email protected]>
CC: Sergey Senozhatsky <[email protected]>
CC: Martin K. Petersen <[email protected]>
CC: "James E.J. Bottomley" <[email protected]>
CC: Tejun Heo <[email protected]>
---
drivers/scsi/scsi_lib.c | 6 +++---
include/scsi/scsi_device.h | 10 ++++++++++
2 files changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index c84f931..f77e801 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1301,7 +1301,7 @@ static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
* commands. The device must be brought online
* before trying any recovery commands.
*/
- sdev_printk(KERN_ERR, sdev,
+ sdev_printk_ratelimited(KERN_ERR, sdev,
"rejecting I/O to offline device\n");
ret = BLKPREP_KILL;
break;
@@ -1310,7 +1310,7 @@ static int scsi_setup_cmnd(struct scsi_device *sdev, struct request *req)
* If the device is fully deleted, we refuse to
* process any commands as well.
*/
- sdev_printk(KERN_ERR, sdev,
+ sdev_printk_ratelimited(KERN_ERR, sdev,
"rejecting I/O to dead device\n");
ret = BLKPREP_KILL;
break;
@@ -1802,7 +1802,7 @@ static void scsi_request_fn(struct request_queue *q)
break;
if (unlikely(!scsi_device_online(sdev))) {
- sdev_printk(KERN_ERR, sdev,
+ sdev_printk_ratelimited(KERN_ERR, sdev,
"rejecting I/O to offline device\n");
scsi_kill_request(req, q);
continue;
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 7ae177c..378d3f2 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -249,6 +249,16 @@ struct scsi_device {
#define sdev_printk(l, sdev, fmt, a...) \
sdev_prefix_printk(l, sdev, NULL, fmt, ##a)
+#define sdev_printk_ratelimited(l, sdev, fmt, a...) \
+({ \
+ static DEFINE_RATELIMIT_STATE(_rs, \
+ DEFAULT_RATELIMIT_INTERVAL, \
+ DEFAULT_RATELIMIT_BURST); \
+ \
+ if (__ratelimit(&_rs)) \
+ sdev_prefix_printk(l, sdev, NULL, fmt, ##a); \
+})
+
__printf(3, 4) void
scmd_printk(const char *, const struct scsi_cmnd *, const char *, ...);
--
1.8.3.1
Hello,
On (04/02/18 09:58), Wen Yang wrote:
> There would be so many same lines printed by frequent printk if one
> disk went wrong, like,
> [ 546.185242] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185258] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185280] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185307] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185334] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185364] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185390] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185410] sd 0:1:0:0: rejecting I/O to offline device
> For slow serial console, the frequent printk may be blocked for a
> long time, and if any spin_lock has been acquired before the printk
> like in scsi_request_fn, watchdog could be triggered.
Did you test the patch? Rate limiting does not completely remove
printk calls. printk is still there, in a loop under spin_lock.
A big enough I/O request queue can cause the same lockup problems.
-ss
Hi, Yang,
On 2018/4/2 9:58, Wen Yang wrote:
> There would be so many same lines printed by frequent printk if one
> disk went wrong, like,
> [ 546.185242] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185258] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185280] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185307] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185334] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185364] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185390] sd 0:1:0:0: rejecting I/O to offline device
> [ 546.185410] sd 0:1:0:0: rejecting I/O to offline device
> For slow serial console, the frequent printk may be blocked for a
> long time, and if any spin_lock has been acquired before the printk
> like in scsi_request_fn, watchdog could be triggered.
>
> Related disscussion can be found here,
> https://bugzilla.kernel.org/show_bug.cgi?id=199003
> And Petr brought the idea to throttle the frequent printk, it's
> useless to print the same lines frequently after all.
>
It's true that this print for the same device is useless. But it's
useful for different devices. Is it possible to limit the print only
for the same device?
Thanks,
Jason
>
>