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    SubjectRe: [PATCH] x86: Issue a warning if number of present CPUs > maxcpus and CONFIG_HOTPLUG=n
    >>> On 15.02.14 at 15:02, Petr Tesarik <ptesarik@suse.cz> wrote:
    > --- a/arch/x86/kernel/smpboot.c
    > +++ b/arch/x86/kernel/smpboot.c
    > @@ -1226,9 +1226,6 @@ __init void prefill_possible_map(void)
    > #ifdef CONFIG_HOTPLUG_CPU
    > if (setup_max_cpus)
    > possible += disabled_cpus;
    > -#else
    > - if (possible > i)
    > - possible = i;
    > #endif
    > } else
    > possible = setup_possible_cpus;

    In between here total_cpus is being set, which now will get a
    larger value if !HOTPLUG_CPU. Did you check that this has no
    unintended side effect? And even if you did, it would still feel
    more safe if you moved that line down after the capping point
    below.

    Similarly (but perhaps less important, albeit possibly slightly
    confusing) the NR_CPUS related warning could now get issued
    along with the warning below (when possible > nr_cpu_ids > i).
    Hence that may better be moved down too (or then in effect
    the if() block you modify below would get moved up). I realize
    that two warning instead of just one would also be possible
    without any change, so you're not really introducing some
    entirely new inconsistency here...

    Jan

    > @@ -1246,7 +1243,7 @@ __init void prefill_possible_map(void)
    > if (!setup_max_cpus)
    > #endif
    > if (possible > i) {
    > - pr_warn("%d Processors exceeds max_cpus limit of %u\n",
    > + pr_warn("%d Processors exceeds maxcpus limit of %u\n",
    > possible, setup_max_cpus);
    > possible = i;
    > }
    > --
    > 1.8.4.5





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