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Annotation of XNU/osfmk/kern/wait_queue.h, revision 1.1

1.1     ! root        1: #ifndef _KERN_WAIT_QUEUE_H_
        !             2: #define _KERN_WAIT_QUEUE_H_
        !             3: 
        !             4: #include <kern/kern_types.h>           /* for wait_queue_t */
        !             5: #include <mach/sync_policy.h>
        !             6: 
        !             7: #ifdef MACH_KERNEL_PRIVATE
        !             8: 
        !             9: #include <kern/lock.h>
        !            10: #include <kern/queue.h>
        !            11: 
        !            12: /*
        !            13:  *     wait_queue_t
        !            14:  *     This is the definition of the common event wait queue
        !            15:  *     that the scheduler APIs understand.  It is used
        !            16:  *     internally by the gerneralized event waiting mechanism
        !            17:  *     (assert_wait), and also for items that maintain their
        !            18:  *     own wait queues (such as ports and semaphores).
        !            19:  *
        !            20:  *     It is not published to other kernel components.  They
        !            21:  *     can create wait queues by calling wait_queue_alloc.
        !            22:  *
        !            23:  *     NOTE:  Hardware locks are used to protect event wait
        !            24:  *     queues since interrupt code is free to post events to
        !            25:  *     them.
        !            26:  */
        !            27: typedef struct wait_queue {
        !            28:     hw_lock_data_t     wq_interlock;   /* interlock */
        !            29:     unsigned int                        /* flags */
        !            30:     /* boolean_t */    wq_fifo:1,      /* fifo wakeup policy? */
        !            31:                        wq_issub:1,     /* is waitq linked? */
        !            32:                        :0;             /* force to long boundary */
        !            33:     queue_head_t       wq_queue;       /* queue of elements */
        !            34: } WaitQueue;
        !            35: 
        !            36: /*
        !            37:  *     wait_queue_sub_t
        !            38:  *     This is the common definition for a subordinate wait queue.
        !            39:  *     These can be linked as members/elements of multiple regular
        !            40:  *     wait queues.  They have an additional set of linkages to
        !            41:  *     identify the linkage structures that point to them.
        !            42:  */
        !            43: typedef struct wait_queue_sub {
        !            44:        WaitQueue       wqs_wait_queue; /* our wait queue */
        !            45:        queue_head_t    wqs_sublinks;   /* links from sub perspective */
        !            46: } WaitQueueSub;
        !            47: 
        !            48: typedef WaitQueueSub *wait_queue_sub_t;
        !            49: 
        !            50: #define WAIT_QUEUE_SUB_NULL ((wait_queue_sub_t)0)
        !            51: 
        !            52: 
        !            53: /*
        !            54:  *     wait_queue_element_t
        !            55:  *     This structure describes the elements on an event wait
        !            56:  *     queue.  It is the common first fields in a thread shuttle
        !            57:  *     and wait_queue_link_t.  In that way, a wait queue can
        !            58:  *     consist of both thread shuttle elements and links off of
        !            59:  *     to other (subordinate) wait queues.
        !            60:  *
        !            61:  *     WARNING: The first three fields of the thread shuttle
        !            62:  *     definition does not use this definition yet.  Any change in
        !            63:  *     the layout here will have to be matched with a change there.
        !            64:  */
        !            65: typedef struct wait_queue_element {
        !            66:        queue_chain_t   wqe_links;      /* link of elements on this queue */
        !            67:        wait_queue_t    wqe_queue;      /* queue this element is on */
        !            68:        event_t         wqe_event;      /* event this element is waiting for */
        !            69: } *wait_queue_element_t;
        !            70: 
        !            71: /*
        !            72:  *     wait_queue_link_t
        !            73:  *     Specialized wait queue element type for linking subordinate
        !            74:  *     event waits queues onto a wait queue.  In this way, an event
        !            75:  *     can be constructed so that any thread waiting on any number
        !            76:  *     of associated wait queues can handle the event, while letting
        !            77:  *     the thread only be linked on the single wait queue it blocked on.
        !            78:  *
        !            79:  *     One use: ports in multiple portsets.  Each thread is queued up
        !            80:  *     on the portset that it specifically blocked on during a receive
        !            81:  *     operation.  Each port's event queue links in all the portset
        !            82:  *     event queues of which it is a member.  An IPC event post associated
        !            83:  *     with that port may wake up any thread from any of those portsets,
        !            84:  *     or one that was waiting locally on the port itself.
        !            85:  */
        !            86: typedef struct wait_queue_link {
        !            87:        struct wait_queue_element       wql_element;    /* element on master */
        !            88:         wait_queue_sub_t               wql_subqueue;   /* sub queue */
        !            89:        queue_chain_t                   wql_sublinks;   /* element on sub */
        !            90: } *wait_queue_link_t;
        !            91: 
        !            92: #define WAIT_QUEUE_LINK_NULL ((wait_queue_link_t)0)
        !            93: 
        !            94: #define wql_links wql_element.wqe_links
        !            95: #define wql_queue wql_element.wqe_queue
        !            96: #define wql_event wql_element.wqe_event
        !            97: 
        !            98: extern int wait_queue_subordinate;
        !            99: #define WAIT_QUEUE_SUBORDINATE &_wait_queue_subordinate
        !           100: 
        !           101: extern void wait_queue_init(
        !           102:                        wait_queue_t wait_queue,
        !           103:                        int policy);
        !           104: 
        !           105: extern kern_return_t wait_queue_link(
        !           106:                        wait_queue_t wait_queue,
        !           107:                        wait_queue_sub_t subordinate_queue);
        !           108: 
        !           109: extern kern_return_t wait_queue_unlink(
        !           110:                        wait_queue_t wait_queue,
        !           111:                        wait_queue_sub_t subordinate_queue);
        !           112: extern void wait_queue_unlink_one(
        !           113:                        wait_queue_t wait_queue,
        !           114:                        wait_queue_sub_t *subordinate_queue_pointer);
        !           115: 
        !           116: extern boolean_t wait_queue_member_queue(
        !           117:                        wait_queue_t wait_queue,
        !           118:                        wait_queue_sub_t subordinate_queue);
        !           119: 
        !           120: extern kern_return_t clear_wait_queue_internal(
        !           121:                        thread_t thread,
        !           122:                        int result);
        !           123: 
        !           124: extern kern_return_t wait_queue_remove(
        !           125:                        thread_t thread);
        !           126: 
        !           127: #define wait_queue_assert_possible(thread) \
        !           128:                        ((thread)->wait_queue == WAIT_QUEUE_NULL)
        !           129: 
        !           130: 
        !           131: #define wait_queue_empty(wq)   (queue_empty(&(wq)->wq_queue))
        !           132: 
        !           133: #define wait_queue_held(wq)    (hw_lock_held(&(wq)->wq_interlock))
        !           134: 
        !           135: #define wait_queue_is_sub(wqs) ((wqs)->wqs_wait_queue.wq_issub)
        !           136: #define wqs_lock(wqs)          wait_queue_lock(&(wqs)->wqs_wait_queue)
        !           137: #define wqs_unlock(wqs)                wait_queue_unlock(&(wqs)->wqs_wait_queue)
        !           138: #define wqs_lock_try(wqs)      wait_queue__try_lock(&(wqs)->wqs_wait_queue)
        !           139: 
        !           140: /******** Decomposed interfaces (to build higher level constructs) ***********/
        !           141: 
        !           142: extern void wait_queue_lock(
        !           143:                        wait_queue_t wait_queue);
        !           144: 
        !           145: extern void wait_queue_unlock(
        !           146:                        wait_queue_t wait_queue);
        !           147: 
        !           148: extern boolean_t wait_queue_lock_try(
        !           149:                        wait_queue_t wait_queue);
        !           150: 
        !           151: /* assert intent to wait on a locked wait queue */
        !           152: extern void wait_queue_assert_wait_locked(
        !           153:                        wait_queue_t wait_queue,
        !           154:                        event_t wait_event,
        !           155:                        int interruptible,
        !           156:                        boolean_t unlock);
        !           157: 
        !           158: /* peek to see which thread would be chosen for a wakeup - but keep on queue */
        !           159: extern void wait_queue_peek_locked(
        !           160:                        wait_queue_t wait_queue,
        !           161:                        event_t event,
        !           162:                        thread_t *thread,
        !           163:                        wait_queue_t *found_queue);
        !           164: 
        !           165: /* peek to see which thread would be chosen for a wakeup - but keep on queue */
        !           166: extern void wait_queue_pull_thread_locked(
        !           167:                        wait_queue_t wait_queue,
        !           168:                        thread_t thread,
        !           169:                        boolean_t unlock);
        !           170: 
        !           171: /* wakeup all threads waiting for a particular event on locked queue */
        !           172: extern kern_return_t  wait_queue_wakeup_one_locked(
        !           173:                        wait_queue_t wait_queue,
        !           174:                        event_t wake_event,
        !           175:                        int result,
        !           176:                        boolean_t unlock);
        !           177: 
        !           178: /* wakeup one thread waiting for a particular event on locked queue */
        !           179: extern kern_return_t  wait_queue_wakeup_one_locked(
        !           180:                        wait_queue_t wait_queue,
        !           181:                        event_t wake_event,
        !           182:                        int result,
        !           183:                        boolean_t unlock);
        !           184: 
        !           185: /* return the identity of a thread that is waiting for <wait_queue, event> */
        !           186: extern thread_t wait_queue_recommend_locked(
        !           187:                        wait_queue_t wait_queue,
        !           188:                        event_t wake_event);
        !           189:                        
        !           190: /* return identity of a thread awakened for a particular <wait_queue,event> */
        !           191: extern thread_t wait_queue_wakeup_identity_locked(
        !           192:                        wait_queue_t wait_queue,
        !           193:                        event_t wake_event,
        !           194:                        int result,
        !           195:                        boolean_t unlock);
        !           196: 
        !           197: /* wakeup thread iff its still waiting for a particular event on locked queue */
        !           198: extern kern_return_t wait_queue_wakeup_thread_locked(
        !           199:                        wait_queue_t wait_queue,
        !           200:                        event_t wake_event,
        !           201:                        thread_t thread,
        !           202:                        int result,
        !           203:                        boolean_t unlock);
        !           204: 
        !           205: #endif /* MACH_KERNEL_PRIVATE */
        !           206: 
        !           207: extern wait_queue_t wait_queue_alloc(
        !           208:                        int policy);
        !           209: 
        !           210: extern void wait_queue_free(
        !           211:                        wait_queue_t wait_queue);
        !           212: 
        !           213: /******** Standalone interfaces (not a part of a higher construct) ************/
        !           214: 
        !           215: /* assert intent to wait on <wait_queue,event> pair */
        !           216: extern void wait_queue_assert_wait(
        !           217:                        wait_queue_t wait_queue,
        !           218:                        event_t wait_event,
        !           219:                        boolean_t interruptible);
        !           220: 
        !           221: /* wakeup the most appropriate thread waiting on <wait_queue,event> pair */
        !           222: extern kern_return_t  wait_queue_wakeup_one(
        !           223:                        wait_queue_t wait_queue,
        !           224:                        event_t wake_event,
        !           225:                        int result);
        !           226: 
        !           227: /* wakeup all the threads waiting on <wait_queue,event> pair */
        !           228: extern kern_return_t  wait_queue_wakeup_all(
        !           229:                        wait_queue_t wait_queue,
        !           230:                        event_t wake_event,
        !           231:                        int result);
        !           232: 
        !           233: /* wakeup a specified thread waiting iff waiting on <wait_queue,event> pair */
        !           234: extern kern_return_t  wait_queue_wakeup_thread(
        !           235:                        wait_queue_t wait_queue,
        !           236:                        event_t wake_event,
        !           237:                        thread_t thread,
        !           238:                        int result);
        !           239: 
        !           240: #endif /* _KERN_WAIT_QUEUE_H_ */

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