Messages in this thread | | | Date | Mon, 25 Jun 2012 17:23:07 -0700 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH v3] printk: Have printk() never buffer its data |
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On Mon, Jun 25, 2012 at 05:01:11PM -0700, Linus Torvalds wrote: > On Mon, Jun 25, 2012 at 4:55 PM, Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > > > Stephen and Ingo, I understand that your tests now would require > > multiple printk() lines, but this affects what, 10 boxes in the world > > that run these tests (I'm not trying to be mean, just understand the > > issues). The fixes that now are in place fix problems for many more > > systems, and provide the infrastructure for proper logging that people > > have been screaming at us for over 10 years to accomplish. > > I disagree violently. > > I think we absolutely should apply Steven's patch. > > Why? Because the buffering does not help *anything*, and it's > surprising, and it breaks one of our main debugging tools. There's no > upside to it.
Ok, but I thought you wanted the "properly handle continuations" that we now have in the kernel. I must be mistaken.
> The fact that we found *one* case where it broke within days of it > being introduced is not the issue. Fixing that one case is irrelevant. > It's the unknown number of other cases that did similar thngs that > matter. > > If there are other places that print out partial lines, they may have > this problem too. Don't buffer. > > And if there are *not* other places that print out partial lines, then > buffering doesn't help. Don't buffer. > > Notice? Buffering partial lines is never *ever* the right thing to do > for something like printk. > > If you want to merge the partial lines, do it at the *logging* stage, > not at the printout stage. Nobody cares if you buffer the stuff that > actually makes it to "dmesg". But buffering the stuff before it makes > it to the screen is just wrong.
Ok, Kay, does Stephen's patch work for you as well? I'll go boot a box with it and look at the output, but that will take 30 minutes or so...
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