Messages in this thread | | | Subject | Re: [PATCH V2 RFC 3/3] kvm: Check system load and handle different commit cases accordingly | From | Peter Zijlstra <> | Date | Mon, 29 Oct 2012 18:54:40 +0100 |
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On Mon, 2012-10-29 at 19:37 +0530, Raghavendra K T wrote: > +/* > + * A load of 2048 corresponds to 1:1 overcommit > + * undercommit threshold is half the 1:1 overcommit > + * overcommit threshold is 1.75 times of 1:1 overcommit threshold > + */ > +#define COMMIT_THRESHOLD (FIXED_1) > +#define UNDERCOMMIT_THRESHOLD (COMMIT_THRESHOLD >> 1) > +#define OVERCOMMIT_THRESHOLD ((COMMIT_THRESHOLD << 1) - > (COMMIT_THRESHOLD >> 2)) > + > +unsigned long kvm_system_load(void) > +{ > + unsigned long load; > + > + load = avenrun[0] + FIXED_1/200; > + load = load / num_online_cpus(); > + > + return load; > +}
ARGH.. no that's wrong.. very wrong.
1) avenrun[] EXPORT_SYMBOL says it should be removed, that's not a joke.
2) avenrun[] is a global load, do not ever use a global load measure
3) avenrun[] has nothing what so ever to do with runqueue lengths, someone with a gazillion tasks in D state will get a huge load but the cpu is very idle.
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