On (12/26/16 19:54), Tetsuo Handa wrote: > I tried these 9 patches. Generally OK. > > Although there is still "schedule_timeout_killable() lockup with oom_lock held" > problem, async-printk patches help avoiding "printk() lockup with oom_lock held" > problem. Thank you. > > Three comments from me. > > (1) Messages from e.g. SysRq-b is not waited for sent to consoles. > "SysRq : Resetting" line is needed as a note that I gave up waiting. > > (2) Messages from e.g. SysRq-t should be sent to consoles synchronously? > "echo t > /proc/sysrq-trigger" case can use asynchronous printing. > But since ALT-SysRq-T sequence from keyboard may be used when scheduler > is not responding, it might be better to use synchronous printing. > (Or define a magic key sequence to toggle synchronous/asynchronous?) it's really hard to tell if the message comes from sysrq or from somewhere else. the current approach -- switch to *always* sync printk once we see the first LOGLEVEL_EMERG message. so you can add printk(LOGLEVEL_EMERG "sysrq-t\n"); for example, and printk will switch to sync mode. sync mode, is might be a bit dangerous though, since we printk from IRQ. -ss -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>