Messages in this thread | | | Date | Mon, 21 Mar 2016 17:51:34 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [RFC][PATCH v5 1/2] printk: Make printk() completely async |
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On (03/21/16 17:07), Byungchul Park wrote: [..] > > > > > It will not print the "lockup suspected" message at all, for e.g. rq->lock, > > > > > p->pi_lock and any locks which are used within wake_up_process(). > > > > > > > > this will switch to old SYNC printk() mode should such a lockup ever > > > > happen, which is a giant advantage over any other implementation; doing > > > > wake_up_process() within the 'we can detect recursive printk() here' > > > > gives us better control. > > > > > > > > why > > > > printk()->IRQ->wake_up_process()->spin_dump()->printk()->IRQ->wake_up_process()->spin_dump()->printk()->IRQ... > > > > is better? > > > > > > What is IRQ? > > > > this is how printk() can print the messages in async mode apart from > > direct and wake_up_process() in vprintk_emit(). > > Do you mean IRQ work?
yes.
> Is there any reason why you don't put the wake_up_process() out of the > critical section
I provided reasons already.
> with my suggestion, even though it can solve the infinite recuresion you worried about?
which is 'a static lock pointer in spin_dump()'? I don't think this will fix recursive printks.
/* seems that for some reason my previous reply was not delivered. re-sending. */
-ss
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