Messages in this thread | | | Date | Sat, 8 Dec 2012 16:02:52 +0100 | From | Ingo Molnar <> | Subject | Re: [GIT PULL v2] printk: Make it usable on nohz cpus |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Ingo, > > Please pull the printk support in dynticks mode patches that can > be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git tags/printk-dynticks-for-mingo-v2 > > for you to fetch changes up to 74876a98a87a115254b3a66a14b27320b7f0acaa: > > printk: Wake up klogd using irq_work (2012-11-18 01:01:49 +0100) > > It is based on v3.7-rc4. > > Changes since previous pull request include support for irq > work flush on CPU offlining and acks from Steve. The rest > hasn't changed except some comment fix.
Since this changes kernel/printk.c it needs Linus's ack.
I looked through the older submissions but found no good summary of these changes: it would be nice if you could write up a good high level description of these changes - why has printk based kernel message logging become problematic on nohz, what are the symptoms to users, and what are the solution alternatives you found and please justify the irq_work extension variant you picked.
I more or less accept the fact that fixes are needed here, but the linecount appears a bit high. It's possibly unavoidable, but would be nice to have a discussion of it, as printk is something we really, really want to keep as simple as possible.
Thanks,
Ingo
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