Messages in this thread | | | Date | Sun, 24 Apr 2016 15:35:22 +0200 | From | Pavel Machek <> | Subject | Re: [RFC][PATCH v6 0/2] printk: Make printk() completely async |
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On Sun 2016-04-24 14:14:49, Sergey Senozhatsky wrote: > On (04/23/16 21:40), Pavel Machek wrote: > [..] > > > > 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. 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? > > > > So... from basically linux 0.0, cli() printk("") could be used for > > debugging. ... and that's now gone. Right? > > > > Can you explain why that is good idea? > > it's not gone. you need to explicitly enable async printk mode. the case > you mentioned -- cli() printk("")->console_unlock() -- apart from being > useful in some scenarios, can cause problems in others, simply because > under some circumstances it can run forever, as long as there are printk() > calls coming from other CPUs (which can happen during, f.e., debugging). > did you mean UP systems? well, async printk is sort of useless on UP systems > anyway.
Well, yes, it has been long known that printk() can take long time.. Still that's not a problem for smaller system.
Now, patch set above says "Make printk() completely async" -- so I assumed that it does...
Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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