bsd/pthread/pthread_priority.c

   1 /*
   2  * Copyright (c) 2017 Apple 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 #include <pthread/priority_private.h>
  31
  32 #ifndef QOS_MIN_RELATIVE_PRIORITY // from <sys/qos.h> in userspace
  33 #define QOS_MIN_RELATIVE_PRIORITY -15
  34 #endif
  35
  36 pthread_priority_compact_t
  37 _pthread_priority_normalize(pthread_priority_t pp)
  38 {
  39         if (pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) {
  40                 return _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG;
  41         }
  42         if (_pthread_priority_has_qos(pp)) {
  43                 int relpri = _pthread_priority_relpri(pp);
  44                 if (relpri > 0 || relpri < QOS_MIN_RELATIVE_PRIORITY) {
  45                         pp |= _PTHREAD_PRIORITY_PRIORITY_MASK;
  46                 }
  47                 return pp & (_PTHREAD_PRIORITY_OVERCOMMIT_FLAG |
  48                        _PTHREAD_PRIORITY_FALLBACK_FLAG |
  49                        _PTHREAD_PRIORITY_QOS_CLASS_MASK |
  50                        _PTHREAD_PRIORITY_PRIORITY_MASK);
  51         }
  52         return _pthread_unspecified_priority();
  53 }
  54
  55 pthread_priority_compact_t
  56 _pthread_priority_normalize_for_ipc(pthread_priority_t pp)
  57 {
  58         if (_pthread_priority_has_qos(pp)) {
  59                 int relpri = _pthread_priority_relpri(pp);
  60                 if (relpri > 0 || relpri < QOS_MIN_RELATIVE_PRIORITY) {
  61                         pp |= _PTHREAD_PRIORITY_PRIORITY_MASK;
  62                 }
  63                 return pp & (_PTHREAD_PRIORITY_QOS_CLASS_MASK |
  64                        _PTHREAD_PRIORITY_PRIORITY_MASK);
  65         }
  66         return _pthread_unspecified_priority();
  67 }
  68
  69 pthread_priority_compact_t
  70 _pthread_priority_combine(pthread_priority_t base_pp, thread_qos_t qos)
  71 {
  72         if (base_pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) {
  73                 return _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG;
  74         }
  75
  76         if (base_pp & _PTHREAD_PRIORITY_FALLBACK_FLAG) {
  77                 if (!qos) {
  78                         return (pthread_priority_compact_t)base_pp;
  79                 }
  80         } else if (qos < _pthread_priority_thread_qos(base_pp)) {
  81                 return (pthread_priority_compact_t)base_pp;
  82         }
  83
  84         return _pthread_priority_make_from_thread_qos(qos, 0,
  85                    base_pp & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG);
  86 }