Messages in this thread | | | Date | Mon, 17 Jun 2019 17:59:31 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] kernel/isolation: Asset that a housekeeping CPU comes up at boot time |
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On Mon, Jun 10, 2019 at 05:24:32PM +1000, Nicholas Piggin wrote: > Nicholas Piggin's on June 1, 2019 9:39 pm: > > With the change to allow the boot CPU0 to be isolated, it is possible > > to specify command line options that result in no housekeeping CPU > > online at boot. > > > > An 8 CPU system booted with "nohz_full=0-6 maxcpus=4", for example. > > > > It is not easily possible at housekeeping init time to know all the > > various SMP options that will result in an invalid configuration, so > > this patch adds a sanity check after SMP init, to ensure that a > > housekeeping CPU has been onlined. > > > > The panic is undesirable, but it's better than the alternative of an > > obscure non deterministic failure. The panic will reliably happen > > when advanced parameters are used incorrectly. > > Ping on this one? This should resolve Frederic's remaining objection > to the series (at least until he solves it more generally). > > As the series has already been merged, should we get this upstream > before release?
I was hoping for feedback from Frederic, lacking that, I've queued it now.
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