49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
/*
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* Ratelimiting calculations
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*
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* Copyright IBM, Corp. 2011
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*
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* Authors:
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* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
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*
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* This work is licensed under the terms of the GNU LGPL, version 2 or later.
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* See the COPYING.LIB file in the top-level directory.
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*
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*/
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#ifndef QEMU_RATELIMIT_H
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#define QEMU_RATELIMIT_H 1
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typedef struct {
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int64_t next_slice_time;
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uint64_t slice_quota;
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uint64_t slice_ns;
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uint64_t dispatched;
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} RateLimit;
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static inline int64_t ratelimit_calculate_delay(RateLimit *limit, uint64_t n)
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{
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int64_t now = qemu_get_clock_ns(rt_clock);
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if (limit->next_slice_time < now) {
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limit->next_slice_time = now + limit->slice_ns;
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limit->dispatched = 0;
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}
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if (limit->dispatched == 0 || limit->dispatched + n <= limit->slice_quota) {
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limit->dispatched += n;
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return 0;
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} else {
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limit->dispatched = n;
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return limit->next_slice_time - now;
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}
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}
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static inline void ratelimit_set_speed(RateLimit *limit, uint64_t speed,
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uint64_t slice_ns)
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{
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limit->slice_ns = slice_ns;
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limit->slice_quota = ((double)speed * 1000000000ULL) / slice_ns;
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}
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#endif
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