Messages in this thread | | | Date | Fri, 30 May 2014 12:10:06 +0200 (CEST) | From | Jiri Kosina <> | Subject | Re: [RFC PATCH 00/11] printk: safe printing in NMI context |
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On Fri, 30 May 2014, Jan Kara wrote:
> > Documentation/kernel-parameters.txt | 19 +- > > kernel/printk/printk.c | 1218 +++++++++++++++++++++++++---------- > > 2 files changed, 878 insertions(+), 359 deletions(-) > > > > > > Your patches look clean and pretty nice actually. They must be seriously > > considered if we want to keep the current locked ring buffer design and > > extend it to multiple per context buffers. But I wonder if it's worth to > > continue that way with the printk ancient design. > > > > If it takes more than 1000 line changes (including 500 added) to make it > > finally work correctly with NMIs by working around its fundamental flaws, > > shouldn't we rather redesign it to use a lockless ring buffer like ftrace > > or perf ones? > I agree that lockless ringbuffer would be a more elegant solution but a > much more intrusive one and complex as well. Petr's patch set basically > leaves ordinary printk path intact to avoid concerns about regressions > there.
Fully agreed, vast majority of the changes done by the patchset are on the unlikely in-NMI path, leaving normal printk operation as-is.
-- Jiri Kosina SUSE Labs
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