180 lines
4.3 KiB
C
180 lines
4.3 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2012 Gleb Smirnoff <glebius@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/sched.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <vm/uma.h>
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#define IN_SUBR_COUNTER_C
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#include <sys/counter.h>
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void
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counter_u64_zero(counter_u64_t c)
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{
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counter_u64_zero_inline(c);
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}
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uint64_t
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counter_u64_fetch(counter_u64_t c)
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{
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return (counter_u64_fetch_inline(c));
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}
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counter_u64_t
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counter_u64_alloc(int flags)
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{
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counter_u64_t r;
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r = uma_zalloc_pcpu(pcpu_zone_64, flags);
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if (r != NULL)
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counter_u64_zero(r);
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return (r);
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}
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void
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counter_u64_free(counter_u64_t c)
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{
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uma_zfree_pcpu(pcpu_zone_64, c);
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}
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int
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sysctl_handle_counter_u64(SYSCTL_HANDLER_ARGS)
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{
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uint64_t out;
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int error;
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out = counter_u64_fetch(*(counter_u64_t *)arg1);
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error = SYSCTL_OUT(req, &out, sizeof(uint64_t));
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if (error || !req->newptr)
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return (error);
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/*
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* Any write attempt to a counter zeroes it.
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*/
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counter_u64_zero(*(counter_u64_t *)arg1);
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return (0);
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}
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int
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sysctl_handle_counter_u64_array(SYSCTL_HANDLER_ARGS)
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{
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uint64_t *out;
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int error;
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out = malloc(arg2 * sizeof(uint64_t), M_TEMP, M_WAITOK);
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for (int i = 0; i < arg2; i++)
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out[i] = counter_u64_fetch(((counter_u64_t *)arg1)[i]);
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error = SYSCTL_OUT(req, out, arg2 * sizeof(uint64_t));
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free(out, M_TEMP);
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if (error || !req->newptr)
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return (error);
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/*
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* Any write attempt to a counter zeroes it.
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*/
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for (int i = 0; i < arg2; i++)
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counter_u64_zero(((counter_u64_t *)arg1)[i]);
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return (0);
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}
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/*
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* MP-friendly version of ppsratecheck().
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*
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* Returns non-negative if we are in the rate, negative otherwise.
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* 0 - rate limit not reached.
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* -1 - rate limit reached.
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* >0 - rate limit was reached before, and was just reset. The return value
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* is number of events since last reset.
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*/
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int64_t
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counter_ratecheck(struct counter_rate *cr, int64_t limit)
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{
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int64_t val;
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int now;
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val = cr->cr_over;
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now = ticks;
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if (now - cr->cr_ticks >= hz) {
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/*
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* Time to clear the structure, we are in the next second.
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* First try unlocked read, and then proceed with atomic.
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*/
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if ((cr->cr_lock == 0) &&
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atomic_cmpset_acq_int(&cr->cr_lock, 0, 1)) {
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/*
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* Check if other thread has just went through the
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* reset sequence before us.
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*/
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if (now - cr->cr_ticks >= hz) {
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val = counter_u64_fetch(cr->cr_rate);
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counter_u64_zero(cr->cr_rate);
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cr->cr_over = 0;
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cr->cr_ticks = now;
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if (val <= limit)
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val = 0;
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}
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atomic_store_rel_int(&cr->cr_lock, 0);
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} else
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/*
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* We failed to lock, in this case other thread may
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* be running counter_u64_zero(), so it is not safe
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* to do an update, we skip it.
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*/
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return (val);
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}
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counter_u64_add(cr->cr_rate, 1);
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if (cr->cr_over != 0)
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return (-1);
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if (counter_u64_fetch(cr->cr_rate) > limit)
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val = cr->cr_over = -1;
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return (val);
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}
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