On 2018/4/3 14:04, 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. v2: fix some typos v3: limit the print only for the same device Suggested-by: Petr Mladek<pmladek@xxxxxxxx> Suggested-by: Sergey Senozhatsky<sergey.senozhatsky.work@xxxxxxxxx> Signed-off-by: Wen Yang<wen.yang99@xxxxxxxxxx> Signed-off-by: Jiang Biao<jiang.biao2@xxxxxxxxxx> Signed-off-by: Tan Hu<tan.hu@xxxxxxxxxx> Reviewed-by: Bart Van Assche<bart.vanassche@xxxxxxx> CC: BartVanAssche<Bart.VanAssche@xxxxxxx> CC: Petr Mladek<pmladek@xxxxxxxx> CC: Sergey Senozhatsky<sergey.senozhatsky.work@xxxxxxxxx> CC: Martin K. Petersen<martin.petersen@xxxxxxxxxx> CC: "James E.J. Bottomley"<jejb@xxxxxxxxxxxxxxxxxx> CC: Tejun Heo<tj@xxxxxxxxxx> CC: JasonYan<yanaijie@xxxxxxxxxx>
In my machine it works fine. Tested-by: Jason Yan <yanaijie@xxxxxxxxxx>
