lib/libzpool/arc_os.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  23  * Copyright (c) 2018, Joyent, Inc.
  24  * Copyright (c) 2011, 2019 by Delphix. All rights reserved.
  25  * Copyright (c) 2014 by Saso Kiselkov. All rights reserved.
  26  * Copyright 2017 Nexenta Systems, Inc.  All rights reserved.
  27  */
  28
  29 #include <sys/zfs_context.h>
  30 #include <sys/arc_impl.h>
  31
  32 /*
  33  * Return a default max arc size based on the amount of physical memory.
  34  * This may be overridden by tuning the zfs_arc_max module parameter.
  35  */
  36 uint64_t
  37 arc_default_max(uint64_t min, uint64_t allmem)
  38 {
  39         uint64_t size;
  40
  41         if (allmem >= 1 << 30)
  42                 size = allmem - (1 << 30);
  43         else
  44                 size = min;
  45         return (MAX(allmem * 5 / 8, size));
  46 }
  47
  48 int64_t
  49 arc_available_memory(void)
  50 {
  51         int64_t lowest = INT64_MAX;
  52
  53         /* Every 100 calls, free a small amount */
  54         if (random_in_range(100) == 0)
  55                 lowest = -1024;
  56
  57         return (lowest);
  58 }
  59
  60 int
  61 arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg)
  62 {
  63         (void) spa, (void) reserve, (void) txg;
  64         return (0);
  65 }
  66
  67 uint64_t
  68 arc_all_memory(void)
  69 {
  70         return (ptob(physmem) / 2);
  71 }
  72
  73 uint64_t
  74 arc_free_memory(void)
  75 {
  76         return (random_in_range(arc_all_memory() * 20 / 100));
  77 }
  78
  79 void
  80 arc_register_hotplug(void)
  81 {
  82 }
  83
  84 void
  85 arc_unregister_hotplug(void)
  86 {
  87 }