5c54f5b9ed
It's going to be used in a later patch. Keep the churn separate. Link: http://lkml.kernel.org/r/20180828172258.3185-6-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Suren Baghdasaryan <surenb@google.com> Tested-by: Daniel Drake <drake@endlessm.com> Cc: Christopher Lameter <cl@linux.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <jweiner@fb.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Enderborg <peter.enderborg@sony.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vinayak Menon <vinmenon@codeaurora.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
49 lines
1.6 KiB
C
49 lines
1.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SCHED_LOADAVG_H
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#define _LINUX_SCHED_LOADAVG_H
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/*
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* These are the constant used to fake the fixed-point load-average
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* counting. Some notes:
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* - 11 bit fractions expand to 22 bits by the multiplies: this gives
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* a load-average precision of 10 bits integer + 11 bits fractional
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* - if you want to count load-averages more often, you need more
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* precision, or rounding will get you. With 2-second counting freq,
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* the EXP_n values would be 1981, 2034 and 2043 if still using only
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* 11 bit fractions.
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*/
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extern unsigned long avenrun[]; /* Load averages */
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extern void get_avenrun(unsigned long *loads, unsigned long offset, int shift);
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#define FSHIFT 11 /* nr of bits of precision */
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#define FIXED_1 (1<<FSHIFT) /* 1.0 as fixed-point */
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#define LOAD_FREQ (5*HZ+1) /* 5 sec intervals */
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#define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */
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#define EXP_5 2014 /* 1/exp(5sec/5min) */
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#define EXP_15 2037 /* 1/exp(5sec/15min) */
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/*
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* a1 = a0 * e + a * (1 - e)
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*/
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static inline unsigned long
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calc_load(unsigned long load, unsigned long exp, unsigned long active)
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{
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unsigned long newload;
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newload = load * exp + active * (FIXED_1 - exp);
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if (active >= load)
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newload += FIXED_1-1;
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return newload / FIXED_1;
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}
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extern unsigned long calc_load_n(unsigned long load, unsigned long exp,
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unsigned long active, unsigned int n);
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#define LOAD_INT(x) ((x) >> FSHIFT)
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#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
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extern void calc_global_load(unsigned long ticks);
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#endif /* _LINUX_SCHED_LOADAVG_H */
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