Messages in this thread | | | Date | Fri, 30 Jun 2017 21:45:16 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [RFC][PATCHv4 0/7] printk: introduce printing kernel threads |
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On (06/30/17 14:11), Petr Mladek wrote: > > 2) can offload printing to other CPUs from vprintk_emit() > > and avoid any of scheduler->timekeeping->etc. paths. which will > > replace printk_deferred(). > > I probably miss something. There is still called wake_up_process() > in this patchset and we could not do this in some scheduler and > timekeeping paths. Also we must not take the console_lock() in > these paths because it calls wake_up_process() as well. But > we want to flush few lines when possible.
yes. but we could call wake_up_process() on !this_cpu. so we wouldn't take this_cpu ->rq lock and so on.
CPU1
vprintk_emit() wake_up_process(printk_kthread on CPU2);
-ss
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