100 lines
2.4 KiB
C
100 lines
2.4 KiB
C
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/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License (the "License").
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* You may not use this file except in compliance with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright (c) 2017, Lawrence Livermore National Security, LLC.
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*/
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#include <sys/zfs_ratelimit.h>
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/*
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* Initialize rate limit struct
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*
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* rl: zfs_ratelimit_t struct
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* burst: Number to allow in an interval before rate limiting
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* interval: Interval time in seconds
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*/
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void
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zfs_ratelimit_init(zfs_ratelimit_t *rl, unsigned int *burst,
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unsigned int interval)
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{
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rl->count = 0;
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rl->start = 0;
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rl->interval = interval;
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rl->burst = burst;
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mutex_init(&rl->lock, NULL, MUTEX_DEFAULT, NULL);
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}
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/*
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* Finalize rate limit struct
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*
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* rl: zfs_ratelimit_t struct
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*/
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void
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zfs_ratelimit_fini(zfs_ratelimit_t *rl)
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{
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mutex_destroy(&rl->lock);
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}
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/*
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* Re-implementation of the kernel's __ratelimit() function
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*
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* We had to write our own rate limiter because the kernel's __ratelimit()
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* function annoyingly prints out how many times it rate limited to the kernel
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* logs (and there's no way to turn it off):
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*
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* __ratelimit: 59 callbacks suppressed
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*
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* If the kernel ever allows us to disable these prints, we should go back to
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* using __ratelimit() instead.
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*
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* Return values are the same as __ratelimit():
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*
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* 0: If we're rate limiting
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* 1: If we're not rate limiting.
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*/
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int
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zfs_ratelimit(zfs_ratelimit_t *rl)
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{
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hrtime_t now;
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hrtime_t elapsed;
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int error = 1;
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mutex_enter(&rl->lock);
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now = gethrtime();
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elapsed = now - rl->start;
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rl->count++;
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if (NSEC2SEC(elapsed) >= rl->interval) {
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rl->start = now;
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rl->count = 0;
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} else {
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if (rl->count >= *rl->burst) {
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error = 0; /* We're ratelimiting */
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}
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}
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mutex_exit(&rl->lock);
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return (error);
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}
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