bsd/kern/kern_memorystatus.c

   1 /*
   2  * Copyright (c) 2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  *
  28  */
  29 /*-
  30  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
  31  * All rights reserved.
  32  *
  33  * Redistribution and use in source and binary forms, with or without
  34  * modification, are permitted provided that the following conditions
  35  * are met:
  36  * 1. Redistributions of source code must retain the above copyright
  37  *    notice, this list of conditions and the following disclaimer.
  38  * 2. Redistributions in binary form must reproduce the above copyright
  39  *    notice, this list of conditions and the following disclaimer in the
  40  *    documentation and/or other materials provided with the distribution.
  41  *
  42  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  43  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  44  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  45  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  46  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  47  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  48  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  49  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  50  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  51  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  52  * SUCH DAMAGE.
  53  */
  54
  55 #include <sys/kern_event.h>
  56 #include <sys/kern_memorystatus.h>
  57
  58 #include <kern/sched_prim.h>
  59 #include <kern/task.h>
  60 #include <kern/thread.h>
  61 #include <libkern/libkern.h>
  62 #include <sys/sysctl.h>
  63
  64 static void kern_memorystatus_thread(void);
  65
  66 int kern_memorystatus_wakeup = 0;
  67 int kern_memorystatus_pause = 0;
  68 int kern_memorystatus_level = 0;
  69 int kern_memorystatus_last_level = 0;
  70 unsigned int kern_memorystatus_kev_failure_count = 0;
  71
  72 SYSCTL_INT(_kern, OID_AUTO, memorystatus_level, CTLFLAG_RD, &kern_memorystatus_level, 0, "");
  73 SYSCTL_UINT(_kern, OID_AUTO, memorystatus_kev_failure_count, CTLFLAG_RD, &kern_memorystatus_kev_failure_count, 0, "");
  74
  75 __private_extern__ void
  76 kern_memorystatus_init(void)
  77 {
  78         (void)kernel_thread(kernel_task, kern_memorystatus_thread);
  79 }
  80
  81 static void
  82 kern_memorystatus_thread(void)
  83 {
  84         struct kev_msg ev_msg;
  85         int ret;
  86
  87         while(1) {
  88
  89                 kern_memorystatus_last_level = kern_memorystatus_level;
  90
  91                 ev_msg.vendor_code    = KEV_VENDOR_APPLE;
  92                 ev_msg.kev_class      = KEV_SYSTEM_CLASS;
  93                 ev_msg.kev_subclass   = KEV_MEMORYSTATUS_SUBCLASS;
  94
  95                 /* pass the memory status level in the event code (as percent used) */
  96                 ev_msg.event_code     = 100 - kern_memorystatus_last_level;
  97
  98                 ev_msg.dv[0].data_length = 0;
  99
 100                 ret = kev_post_msg(&ev_msg);
 101                 if (ret) {
 102                         kern_memorystatus_kev_failure_count++;
 103                         printf("%s: kev_post_msg() failed, err %d\n", __func__, ret);
 104                 }
 105
 106                 assert_wait_timeout((event_t)&kern_memorystatus_pause, THREAD_UNINT, 1, 250*1000*NSEC_PER_USEC);
 107                 (void)thread_block(THREAD_CONTINUE_NULL);
 108
 109                 if (kern_memorystatus_level >= kern_memorystatus_last_level + 5 ||
 110                     kern_memorystatus_level <= kern_memorystatus_last_level - 5)
 111                         continue;
 112
 113                 assert_wait(&kern_memorystatus_wakeup, THREAD_UNINT);
 114                 (void)thread_block((thread_continue_t)kern_memorystatus_thread);
 115         }
 116 }