root/kernel/rcu/rcu_segcblist.h

INCLUDED FROM

DEFINITIONS

1. rcu_cblist_n_cbs
2. rcu_cblist_dequeued_lazy
3. rcu_segcblist_empty
4. rcu_segcblist_n_cbs
5. rcu_segcblist_n_lazy_cbs
6. rcu_segcblist_n_nonlazy_cbs
7. rcu_segcblist_is_enabled
8. rcu_segcblist_is_offloaded
9. rcu_segcblist_restempty

   1 /* SPDX-License-Identifier: GPL-2.0+ */
   2 /*
   3  * RCU segmented callback lists, internal-to-rcu header file
   4  *
   5  * Copyright IBM Corporation, 2017
   6  *
   7  * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
   8  */
   9 
  10 #include <linux/rcu_segcblist.h>
  11 
  12 /* Return number of callbacks in the specified callback list. */
  13 static inline long rcu_cblist_n_cbs(struct rcu_cblist *rclp)
  14 {
  15         return READ_ONCE(rclp->len);
  16 }
  17 
  18 /*
  19  * Account for the fact that a previously dequeued callback turned out
  20  * to be marked as lazy.
  21  */
  22 static inline void rcu_cblist_dequeued_lazy(struct rcu_cblist *rclp)
  23 {
  24         rclp->len_lazy--;
  25 }
  26 
  27 void rcu_cblist_init(struct rcu_cblist *rclp);
  28 void rcu_cblist_enqueue(struct rcu_cblist *rclp, struct rcu_head *rhp);
  29 void rcu_cblist_flush_enqueue(struct rcu_cblist *drclp,
  30                               struct rcu_cblist *srclp,
  31                               struct rcu_head *rhp);
  32 struct rcu_head *rcu_cblist_dequeue(struct rcu_cblist *rclp);
  33 
  34 /*
  35  * Is the specified rcu_segcblist structure empty?
  36  *
  37  * But careful!  The fact that the ->head field is NULL does not
  38  * necessarily imply that there are no callbacks associated with
  39  * this structure.  When callbacks are being invoked, they are
  40  * removed as a group.  If callback invocation must be preempted,
  41  * the remaining callbacks will be added back to the list.  Either
  42  * way, the counts are updated later.
  43  *
  44  * So it is often the case that rcu_segcblist_n_cbs() should be used
  45  * instead.
  46  */
  47 static inline bool rcu_segcblist_empty(struct rcu_segcblist *rsclp)
  48 {
  49         return !READ_ONCE(rsclp->head);
  50 }
  51 
  52 /* Return number of callbacks in segmented callback list. */
  53 static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
  54 {
  55 #ifdef CONFIG_RCU_NOCB_CPU
  56         return atomic_long_read(&rsclp->len);
  57 #else
  58         return READ_ONCE(rsclp->len);
  59 #endif
  60 }
  61 
  62 /* Return number of lazy callbacks in segmented callback list. */
  63 static inline long rcu_segcblist_n_lazy_cbs(struct rcu_segcblist *rsclp)
  64 {
  65         return rsclp->len_lazy;
  66 }
  67 
  68 /* Return number of lazy callbacks in segmented callback list. */
  69 static inline long rcu_segcblist_n_nonlazy_cbs(struct rcu_segcblist *rsclp)
  70 {
  71         return rcu_segcblist_n_cbs(rsclp) - rsclp->len_lazy;
  72 }
  73 
  74 /*
  75  * Is the specified rcu_segcblist enabled, for example, not corresponding
  76  * to an offline CPU?
  77  */
  78 static inline bool rcu_segcblist_is_enabled(struct rcu_segcblist *rsclp)
  79 {
  80         return rsclp->enabled;
  81 }
  82 
  83 /* Is the specified rcu_segcblist offloaded?  */
  84 static inline bool rcu_segcblist_is_offloaded(struct rcu_segcblist *rsclp)
  85 {
  86         return rsclp->offloaded;
  87 }
  88 
  89 /*
  90  * Are all segments following the specified segment of the specified
  91  * rcu_segcblist structure empty of callbacks?  (The specified
  92  * segment might well contain callbacks.)
  93  */
  94 static inline bool rcu_segcblist_restempty(struct rcu_segcblist *rsclp, int seg)
  95 {
  96         return !READ_ONCE(*READ_ONCE(rsclp->tails[seg]));
  97 }
  98 
  99 void rcu_segcblist_inc_len(struct rcu_segcblist *rsclp);
 100 void rcu_segcblist_init(struct rcu_segcblist *rsclp);
 101 void rcu_segcblist_disable(struct rcu_segcblist *rsclp);
 102 void rcu_segcblist_offload(struct rcu_segcblist *rsclp);
 103 bool rcu_segcblist_ready_cbs(struct rcu_segcblist *rsclp);
 104 bool rcu_segcblist_pend_cbs(struct rcu_segcblist *rsclp);
 105 struct rcu_head *rcu_segcblist_first_cb(struct rcu_segcblist *rsclp);
 106 struct rcu_head *rcu_segcblist_first_pend_cb(struct rcu_segcblist *rsclp);
 107 bool rcu_segcblist_nextgp(struct rcu_segcblist *rsclp, unsigned long *lp);
 108 void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp,
 109                            struct rcu_head *rhp, bool lazy);
 110 bool rcu_segcblist_entrain(struct rcu_segcblist *rsclp,
 111                            struct rcu_head *rhp, bool lazy);
 112 void rcu_segcblist_extract_count(struct rcu_segcblist *rsclp,
 113                                  struct rcu_cblist *rclp);
 114 void rcu_segcblist_extract_done_cbs(struct rcu_segcblist *rsclp,
 115                                     struct rcu_cblist *rclp);
 116 void rcu_segcblist_extract_pend_cbs(struct rcu_segcblist *rsclp,
 117                                     struct rcu_cblist *rclp);
 118 void rcu_segcblist_insert_count(struct rcu_segcblist *rsclp,
 119                                 struct rcu_cblist *rclp);
 120 void rcu_segcblist_insert_done_cbs(struct rcu_segcblist *rsclp,
 121                                    struct rcu_cblist *rclp);
 122 void rcu_segcblist_insert_pend_cbs(struct rcu_segcblist *rsclp,
 123                                    struct rcu_cblist *rclp);
 124 void rcu_segcblist_advance(struct rcu_segcblist *rsclp, unsigned long seq);
 125 bool rcu_segcblist_accelerate(struct rcu_segcblist *rsclp, unsigned long seq);
 126 void rcu_segcblist_merge(struct rcu_segcblist *dst_rsclp,
 127                          struct rcu_segcblist *src_rsclp);