Messages in this thread | | | Date | Thu, 12 Oct 2017 13:34:39 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH 1/3] printk: Fix kdb_trap_printk placement |
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On Thu, Oct 12, 2017 at 12:03:04PM +0200, Petr Mladek wrote: > On Thu 2017-10-12 11:45:37, Petr Mladek wrote: > > Hi, > > > > I thought about this a lot from several angles. And I would prefer > > sligly different placement, see the patch below. > > > > On Thu 2017-09-28 14:18:24, Peter Zijlstra wrote: > > > Some people figured vprintk_emit() makes for a nice API and exported > > > it, bypassing the kdb trap. > > > > Sigh, printk() API is pretty complicated and this export > > made it much worse. Well, there are two things: > > > > First, kdb_trap_printk name is a bit misleading. It is not a > > generic trap of any printk message. Instead it seems to be > > used to redirect only particular messages from some existing > > functions, e.g. show_regs() called from kdb_dumpregs(). > > > > Second, it seems that the only user of the exported vprintk_emit() > > is dev_vprintk_emit(). I believe that code using this wrapper > > is not called in the sections where kdb_trap_printk is incremented. > > Well, I wonder if we should go even further and stop exporting > vprintk_emit(). IMHO, the only reason was dev_print_emit() and > the ability to pass the extra "dict" parameter.
You have my blessing there, but the device folks might have an opinion on that; Cc'ed Gregkh.
> My aim is to redirect all the exported interfaces into vprintk_func > (need another name?) where the right implementation will be chosen > by the context (NMI, printk_safe, kdb, deferred?, printk_early, normal). > > In each case, I would like to have all these re-directions on a single > place to make the printk() code better readable. > > IMHO, it would make sense to do this clean up first before > this patchset adds more twists. But I am afraid that we will > meet some problems and it make take longer. I am open for > opinions. > > Best Regards, > Petr
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