arc_os.c

// SPDX-License-Identifier: CDDL-1.0
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or https://opensource.org/licenses/CDDL-1.0.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright (c) 2018, Joyent, Inc.
 * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
 * Copyright (c) 2014 by Saso Kiselkov. All rights reserved.
 * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
 */

#include <sys/zfs_context.h>
#include <sys/arc_impl.h>

/*
 * Return a default max arc size based on the amount of physical memory.
 * This may be overridden by tuning the zfs_arc_max module parameter.
 */
uint64_t
arc_default_max(uint64_t min, uint64_t allmem)
{
	uint64_t size;

	if (allmem >= 1 << 30)
		size = allmem - (1 << 30);
	else
		size = min;
	return (MAX(allmem * 5 / 8, size));
}

int64_t
arc_available_memory(void)
{
	int64_t lowest = INT64_MAX;

	/* Every 100 calls, free a small amount */
	if (random_in_range(100) == 0)
		lowest = -1024;

	return (lowest);
}

int
arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg)
{
	(void) spa, (void) reserve, (void) txg;
	return (0);
}

uint64_t
arc_all_memory(void)
{
	return (ptob(physmem) / 2);
}

uint64_t
arc_free_memory(void)
{
	return (random_in_range(arc_all_memory() * 20 / 100));
}

void
arc_register_hotplug(void)
{
}

void
arc_unregister_hotplug(void)
{
}