Hello Jan, On (03/22/16 07:49), Jan Kara wrote: > Hi, > > On Tue 22-03-16 02:25:28, Sergey Senozhatsky wrote: > > The patch set is based on slightly updated Jan Kara's patches. > > > > This patch set makes printk() completely asynchronous: new messages > > are getting upended to the kernel printk buffer, but instead of 'direct' > > printing the actual print job is performed by a dedicated kthread. > > This has the advantage that printing always happens from a schedulable > > context and thus we don't lockup any particular CPU or even interrupts. > > > > The patch set is against next-20160321 > > > > the series in total has 3 patches: > > - printk: Make printk() completely async > > - printk: Make wake_up_klogd_work_func() async > > - printk: make console_unlock() async > > > > per discussion, "printk: make console_unlock() async" will be posted > > later on. > > Patches look good to me. I don't think you need to mention the > console_unlock() async patch when it is not part of the series.
thanks. > BTW, you seemed to have dropped my patch to skip if there are too > many buffered messages when oops is in progress. Any reason for that? I did. seems that my box has some problems with emails delivery recently: http://marc.info/?l=linux-kernel&m=145821214108806 in short, I'm afraid we can lose valuable data in some cases. for example : hardlockup detector with sysctl_hardlockup_all_cpu_backtrace. : : static void watchdog_overflow_callback(...) : { : ... : if (is_hardlockup()) { : ... : if (sysctl_hardlockup_all_cpu_backtrace && : !test_and_set_bit(0, &hardlockup_allcpu_dumped)) : trigger_allbutself_cpu_backtrace(); : : nmi_panic(regs, msg); : ... : } : ... : } : : trigger_allbutself_cpu_backtrace() can be much more than 100 lines. : trigger_allbutself_cpu_backtrace() may or may not be implemented via : NMI. for example arch/sparc/kernel/process_64.c on a large enough system trigger_allbutself_cpu_backtrace() can easily be more than 100 lines, and trigger_allbutself_cpu_backtrace() may not be able to print the backtraces to console (for example this hardlockuped CPU owns the console_sem) before CPU declares oops_in_progress in nmi_panic()->panic(). -ss
