1 /* delayacct.h - per-task delay accounting 2 * 3 * Copyright (C) Shailabh Nagar, IBM Corp. 2006 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation; either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See 13 * the GNU General Public License for more details. 14 * 15 */ 16 17 #ifndef _LINUX_DELAYACCT_H 18 #define _LINUX_DELAYACCT_H 19 20 #include <uapi/linux/taskstats.h> 21 #include <linux/sched.h> 22 #include <linux/slab.h> 23 24 /* 25 * Per-task flags relevant to delay accounting 26 * maintained privately to avoid exhausting similar flags in sched.h:PF_* 27 * Used to set current->delays->flags 28 */ 29 #define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */ 30 #define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */ 31 32 #ifdef CONFIG_TASK_DELAY_ACCT 33 34 extern int delayacct_on; /* Delay accounting turned on/off */ 35 extern struct kmem_cache *delayacct_cache; 36 extern void delayacct_init(void); 37 extern void __delayacct_tsk_init(struct task_struct *); 38 extern void __delayacct_tsk_exit(struct task_struct *); 39 extern void __delayacct_blkio_start(void); 40 extern void __delayacct_blkio_end(void); 41 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *); 42 extern __u64 __delayacct_blkio_ticks(struct task_struct *); 43 extern void __delayacct_freepages_start(void); 44 extern void __delayacct_freepages_end(void); 45 46 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) 47 { 48 if (p->delays) 49 return (p->delays->flags & DELAYACCT_PF_BLKIO); 50 else 51 return 0; 52 } 53 54 static inline void delayacct_set_flag(int flag) 55 { 56 if (current->delays) 57 current->delays->flags |= flag; 58 } 59 60 static inline void delayacct_clear_flag(int flag) 61 { 62 if (current->delays) 63 current->delays->flags &= ~flag; 64 } 65 66 static inline void delayacct_tsk_init(struct task_struct *tsk) 67 { 68 /* reinitialize in case parent's non-null pointer was dup'ed*/ 69 tsk->delays = NULL; 70 if (delayacct_on) 71 __delayacct_tsk_init(tsk); 72 } 73 74 /* Free tsk->delays. Called from bad fork and __put_task_struct 75 * where there's no risk of tsk->delays being accessed elsewhere 76 */ 77 static inline void delayacct_tsk_free(struct task_struct *tsk) 78 { 79 if (tsk->delays) 80 kmem_cache_free(delayacct_cache, tsk->delays); 81 tsk->delays = NULL; 82 } 83 84 static inline void delayacct_blkio_start(void) 85 { 86 delayacct_set_flag(DELAYACCT_PF_BLKIO); 87 if (current->delays) 88 __delayacct_blkio_start(); 89 } 90 91 static inline void delayacct_blkio_end(void) 92 { 93 if (current->delays) 94 __delayacct_blkio_end(); 95 delayacct_clear_flag(DELAYACCT_PF_BLKIO); 96 } 97 98 static inline int delayacct_add_tsk(struct taskstats *d, 99 struct task_struct *tsk) 100 { 101 if (!delayacct_on || !tsk->delays) 102 return 0; 103 return __delayacct_add_tsk(d, tsk); 104 } 105 106 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 107 { 108 if (tsk->delays) 109 return __delayacct_blkio_ticks(tsk); 110 return 0; 111 } 112 113 static inline void delayacct_freepages_start(void) 114 { 115 if (current->delays) 116 __delayacct_freepages_start(); 117 } 118 119 static inline void delayacct_freepages_end(void) 120 { 121 if (current->delays) 122 __delayacct_freepages_end(); 123 } 124 125 #else 126 static inline void delayacct_set_flag(int flag) 127 {} 128 static inline void delayacct_clear_flag(int flag) 129 {} 130 static inline void delayacct_init(void) 131 {} 132 static inline void delayacct_tsk_init(struct task_struct *tsk) 133 {} 134 static inline void delayacct_tsk_free(struct task_struct *tsk) 135 {} 136 static inline void delayacct_blkio_start(void) 137 {} 138 static inline void delayacct_blkio_end(void) 139 {} 140 static inline int delayacct_add_tsk(struct taskstats *d, 141 struct task_struct *tsk) 142 { return 0; } 143 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 144 { return 0; } 145 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) 146 { return 0; } 147 static inline void delayacct_freepages_start(void) 148 {} 149 static inline void delayacct_freepages_end(void) 150 {} 151 152 #endif /* CONFIG_TASK_DELAY_ACCT */ 153 154 #endif 155