freebsd-dev/sys/kern/subr_counter.c
Pedro F. Giffuni 8a36da99de sys/kern: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 15:20:12 +00:00

180 lines
4.3 KiB
C

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