1 files changed, 73 insertions, 13 deletions

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 8e8287a983c2..b40ac5706040 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -48,14 +48,14 @@
 #elif NR_CPUS <= RCU_FANOUT_SQ
 #  define NUM_RCU_LVLS        2
 #  define NUM_RCU_LVL_0       1
-#  define NUM_RCU_LVL_1       (((NR_CPUS) + RCU_FANOUT - 1) / RCU_FANOUT)
+#  define NUM_RCU_LVL_1       DIV_ROUND_UP(NR_CPUS, RCU_FANOUT)
 #  define NUM_RCU_LVL_2       (NR_CPUS)
 #  define NUM_RCU_LVL_3       0
 #elif NR_CPUS <= RCU_FANOUT_CUBE
 #  define NUM_RCU_LVLS        3
 #  define NUM_RCU_LVL_0       1
-#  define NUM_RCU_LVL_1       (((NR_CPUS) + RCU_FANOUT_SQ - 1) / RCU_FANOUT_SQ)
-#  define NUM_RCU_LVL_2       (((NR_CPUS) + (RCU_FANOUT) - 1) / (RCU_FANOUT))
+#  define NUM_RCU_LVL_1       DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ)
+#  define NUM_RCU_LVL_2       DIV_ROUND_UP(NR_CPUS, RCU_FANOUT)
 #  define NUM_RCU_LVL_3       NR_CPUS
 #else
 # error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
@@ -79,15 +79,21 @@ struct rcu_dynticks {
  * Definition for node within the RCU grace-period-detection hierarchy.
  */
 struct rcu_node {
-        spinlock_t lock;
+        spinlock_t lock;        /* Root rcu_node's lock protects some */
+                                /*  rcu_state fields as well as following. */
         long    gpnum;          /* Current grace period for this node. */
                                 /*  This will either be equal to or one */
                                 /*  behind the root rcu_node's gpnum. */
         unsigned long qsmask;   /* CPUs or groups that need to switch in */
                                 /*  order for current grace period to proceed.*/
+                                /*  In leaf rcu_node, each bit corresponds to */
+                                /*  an rcu_data structure, otherwise, each */
+                                /*  bit corresponds to a child rcu_node */
+                                /*  structure. */
         unsigned long qsmaskinit;
                                 /* Per-GP initialization for qsmask. */
         unsigned long grpmask;  /* Mask to apply to parent qsmask. */
+                                /*  Only one bit will be set in this mask. */
         int     grplo;          /* lowest-numbered CPU or group here. */
         int     grphi;          /* highest-numbered CPU or group here. */
         u8      grpnum;         /* CPU/group number for next level up. */
@@ -95,8 +101,23 @@ struct rcu_node {
         struct rcu_node *parent;
         struct list_head blocked_tasks[2];
                                 /* Tasks blocked in RCU read-side critsect. */
+                                /*  Grace period number (->gpnum) x blocked */
+                                /*  by tasks on the (x & 0x1) element of the */
+                                /*  blocked_tasks[] array. */
 } ____cacheline_internodealigned_in_smp;
 
+/*
+ * Do a full breadth-first scan of the rcu_node structures for the
+ * specified rcu_state structure.
+ */
+#define rcu_for_each_node_breadth_first(rsp, rnp) \
+        for ((rnp) = &(rsp)->node[0]; \
+             (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
+
+#define rcu_for_each_leaf_node(rsp, rnp) \
+        for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
+             (rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
+
 /* Index values for nxttail array in struct rcu_data. */
 #define RCU_DONE_TAIL           0       /* Also RCU_WAIT head. */
 #define RCU_WAIT_TAIL           1       /* Also RCU_NEXT_READY head. */
@@ -126,19 +147,22 @@ struct rcu_data {
          * Any of the partitions might be empty, in which case the
          * pointer to that partition will be equal to the pointer for
          * the following partition.  When the list is empty, all of
-         * the nxttail elements point to nxtlist, which is NULL.
+         * the nxttail elements point to the ->nxtlist pointer itself,
+         * which in that case is NULL.
          *
-         * [*nxttail[RCU_NEXT_READY_TAIL], NULL = *nxttail[RCU_NEXT_TAIL]):
-         *      Entries that might have arrived after current GP ended
-         * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
-         *      Entries known to have arrived before current GP ended
-         * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
-         *      Entries that batch # <= ->completed - 1: waiting for current GP
          * [nxtlist, *nxttail[RCU_DONE_TAIL]):
          *      Entries that batch # <= ->completed
          *      The grace period for these entries has completed, and
          *      the other grace-period-completed entries may be moved
          *      here temporarily in rcu_process_callbacks().
+         * [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
+         *      Entries that batch # <= ->completed - 1: waiting for current GP
+         * [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
+         *      Entries known to have arrived before current GP ended
+         * [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]):
+         *      Entries that might have arrived after current GP ended
+         *      Note that the value of *nxttail[RCU_NEXT_TAIL] will
+         *      always be NULL, as this is the end of the list.
          */
         struct rcu_head *nxtlist;
         struct rcu_head **nxttail[RCU_NEXT_SIZE];
@@ -216,8 +240,19 @@ struct rcu_state {
                                                 /* Force QS state. */
         long    gpnum;                          /* Current gp number. */
         long    completed;                      /* # of last completed gp. */
+
+        /* End  of fields guarded by root rcu_node's lock. */
+
         spinlock_t onofflock;                   /* exclude on/offline and */
-                                                /*  starting new GP. */
+                                                /*  starting new GP.  Also */
+                                                /*  protects the following */
+                                                /*  orphan_cbs fields. */
+        struct rcu_head *orphan_cbs_list;       /* list of rcu_head structs */
+                                                /*  orphaned by all CPUs in */
+                                                /*  a given leaf rcu_node */
+                                                /*  going offline. */
+        struct rcu_head **orphan_cbs_tail;      /* And tail pointer. */
+        long orphan_qlen;                       /* Number of orphaned cbs. */
         spinlock_t fqslock;                     /* Only one task forcing */
                                                 /*  quiescent states. */
         unsigned long jiffies_force_qs;         /* Time at which to invoke */
@@ -255,5 +290,30 @@ extern struct rcu_state rcu_preempt_state;
 DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 
-#endif /* #ifdef RCU_TREE_NONCORE */
+#else /* #ifdef RCU_TREE_NONCORE */
+
+/* Forward declarations for rcutree_plugin.h */
+static inline void rcu_bootup_announce(void);
+long rcu_batches_completed(void);
+static void rcu_preempt_note_context_switch(int cpu);
+static int rcu_preempted_readers(struct rcu_node *rnp);
+#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
+static void rcu_print_task_stall(struct rcu_node *rnp);
+#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
+#ifdef CONFIG_HOTPLUG_CPU
+static void rcu_preempt_offline_tasks(struct rcu_state *rsp,
+                                      struct rcu_node *rnp,
+                                      struct rcu_data *rdp);
+static void rcu_preempt_offline_cpu(int cpu);
+#endif /* #ifdef CONFIG_HOTPLUG_CPU */
+static void rcu_preempt_check_callbacks(int cpu);
+static void rcu_preempt_process_callbacks(void);
+void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
+static int rcu_preempt_pending(int cpu);
+static int rcu_preempt_needs_cpu(int cpu);
+static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
+static void rcu_preempt_send_cbs_to_orphanage(void);
+static void __init __rcu_init_preempt(void);
 
+#endif /* #else #ifdef RCU_TREE_NONCORE */