rcu: merge TREE_PREEPT_RCU blocked_tasks[] lists

[deliverable/linux.git] / kernel / rcutree.h

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index e1a6663c01554fd0461fa39129cb2818bc5a1782..5a439c180e69efe0b2fc7a274e3d918eb4f991d2 100644 (file)
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -84,11 +84,9 @@
  * Dynticks per-CPU state.
  */
 struct rcu_dynticks {
-       int dynticks_nesting;   /* Track nesting level, sort of. */
-       int dynticks;           /* Even value for dynticks-idle, else odd. */
-       int dynticks_nmi;       /* Even value for either dynticks-idle or */
-                               /*  not in nmi handler, else odd.  So this */
-                               /*  remains even for nmi from irq handler. */
+       int dynticks_nesting;   /* Track irq/process nesting level. */
+       int dynticks_nmi_nesting; /* Track NMI nesting level. */
+       atomic_t dynticks;      /* Even value for dynticks-idle, else odd. */
 };
 
 /*
@@ -109,7 +107,7 @@ struct rcu_node {
                                /*  an rcu_data structure, otherwise, each */
                                /*  bit corresponds to a child rcu_node */
                                /*  structure. */
-       unsigned long expmask;  /* Groups that have ->blocked_tasks[] */
+       unsigned long expmask;  /* Groups that have ->blkd_tasks */
                                /*  elements that need to drain to allow the */
                                /*  current expedited grace period to */
                                /*  complete (only for TREE_PREEMPT_RCU). */
@@ -122,11 +120,20 @@ struct rcu_node {
        u8      grpnum;         /* CPU/group number for next level up. */
        u8      level;          /* root is at level 0. */
        struct rcu_node *parent;
-       struct list_head blocked_tasks[4];
-                               /* 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. */
+       struct list_head blkd_tasks;
+                               /* Tasks blocked in RCU read-side critical */
+                               /*  section.  Tasks are placed at the head */
+                               /*  of this list and age towards the tail. */
+       struct list_head *gp_tasks;
+                               /* Pointer to the first task blocking the */
+                               /*  current grace period, or NULL if there */
+                               /*  is no such task. */
+       struct list_head *exp_tasks;
+                               /* Pointer to the first task blocking the */
+                               /*  current expedited grace period, or NULL */
+                               /*  if there is no such task.  If there */
+                               /*  is no current expedited grace period, */
+                               /*  then there can cannot be any such task. */
 } ____cacheline_internodealigned_in_smp;
 
 /*
@@ -218,7 +225,6 @@ struct rcu_data {
        /* 3) dynticks interface. */
        struct rcu_dynticks *dynticks;  /* Shared per-CPU dynticks state. */
        int dynticks_snap;              /* Per-GP tracking for dynticks. */
-       int dynticks_nmi_snap;          /* Per-GP tracking for dynticks_nmi. */
 #endif /* #ifdef CONFIG_NO_HZ */
 
        /* 4) reasons this CPU needed to be kicked by force_quiescent_state */