1 files changed, 30 insertions, 237 deletions

diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 5a5153806c4..9642c6bcb39 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -24,278 +24,71 @@
  * and inputs from Rusty Russell, Andrea Arcangeli and Andi Kleen.
  *
  * For detailed explanation of Read-Copy Update mechanism see -
- * 	Documentation/RCU
+ *	Documentation/RCU
  */
 
 #ifndef __LINUX_RCUTREE_H
 #define __LINUX_RCUTREE_H
 
-#include <linux/cache.h>
-#include <linux/spinlock.h>
-#include <linux/threads.h>
-#include <linux/cpumask.h>
-#include <linux/seqlock.h>
+struct notifier_block;
 
-/*
- * Define shape of hierarchy based on NR_CPUS and CONFIG_RCU_FANOUT.
- * In theory, it should be possible to add more levels straightforwardly.
- * In practice, this has not been tested, so there is probably some
- * bug somewhere.
- */
-#define MAX_RCU_LVLS 3
-#define RCU_FANOUT	      (CONFIG_RCU_FANOUT)
-#define RCU_FANOUT_SQ	      (RCU_FANOUT * RCU_FANOUT)
-#define RCU_FANOUT_CUBE	      (RCU_FANOUT_SQ * RCU_FANOUT)
-
-#if NR_CPUS <= RCU_FANOUT
-#  define NUM_RCU_LVLS	      1
-#  define NUM_RCU_LVL_0	      1
-#  define NUM_RCU_LVL_1	      (NR_CPUS)
-#  define NUM_RCU_LVL_2	      0
-#  define NUM_RCU_LVL_3	      0
-#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_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_3	      NR_CPUS
-#else
-# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
-#endif /* #if (NR_CPUS) <= RCU_FANOUT */
-
-#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3)
-#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
-
-/*
- * 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. */
-};
-
-/*
- * Definition for node within the RCU grace-period-detection hierarchy.
- */
-struct rcu_node {
-	spinlock_t lock;
-	unsigned long qsmask;	/* CPUs or groups that need to switch in */
-				/*  order for current grace period to proceed.*/
-	unsigned long qsmaskinit;
-				/* Per-GP initialization for qsmask. */
-	unsigned long grpmask;	/* Mask to apply to parent qsmask. */
-	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. */
-	u8	level;		/* root is at level 0. */
-	struct rcu_node *parent;
-} ____cacheline_internodealigned_in_smp;
-
-/* 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. */
-#define RCU_NEXT_READY_TAIL	2	/* Also RCU_NEXT head. */
-#define RCU_NEXT_TAIL		3
-#define RCU_NEXT_SIZE		4
-
-/* Per-CPU data for read-copy update. */
-struct rcu_data {
-	/* 1) quiescent-state and grace-period handling : */
-	long		completed;	/* Track rsp->completed gp number */
-					/*  in order to detect GP end. */
-	long		gpnum;		/* Highest gp number that this CPU */
-					/*  is aware of having started. */
-	long		passed_quiesc_completed;
-					/* Value of completed at time of qs. */
-	bool		passed_quiesc;	/* User-mode/idle loop etc. */
-	bool		qs_pending;	/* Core waits for quiesc state. */
-	bool		beenonline;	/* CPU online at least once. */
-	struct rcu_node *mynode;	/* This CPU's leaf of hierarchy */
-	unsigned long grpmask;		/* Mask to apply to leaf qsmask. */
-
-	/* 2) batch handling */
-	/*
-	 * If nxtlist is not NULL, it is partitioned as follows.
-	 * 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.
-	 *
-	 * [*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().
-	 */
-	struct rcu_head *nxtlist;
-	struct rcu_head **nxttail[RCU_NEXT_SIZE];
-	long		qlen; 	 	/* # of queued callbacks */
-	long		blimit;		/* Upper limit on a processed batch */
-
-#ifdef CONFIG_NO_HZ
-	/* 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 */
-#ifdef CONFIG_NO_HZ
-	unsigned long dynticks_fqs;	/* Kicked due to dynticks idle. */
-#endif /* #ifdef CONFIG_NO_HZ */
-	unsigned long offline_fqs;	/* Kicked due to being offline. */
-	unsigned long resched_ipi;	/* Sent a resched IPI. */
-
-	/* 5) __rcu_pending() statistics. */
-	long n_rcu_pending;		/* rcu_pending() calls since boot. */
-	long n_rp_qs_pending;
-	long n_rp_cb_ready;
-	long n_rp_cpu_needs_gp;
-	long n_rp_gp_completed;
-	long n_rp_gp_started;
-	long n_rp_need_fqs;
-	long n_rp_need_nothing;
-
-	int cpu;
-};
-
-/* Values for signaled field in struct rcu_state. */
-#define RCU_GP_INIT		0	/* Grace period being initialized. */
-#define RCU_SAVE_DYNTICK	1	/* Need to scan dyntick state. */
-#define RCU_FORCE_QS		2	/* Need to force quiescent state. */
-#ifdef CONFIG_NO_HZ
-#define RCU_SIGNAL_INIT		RCU_SAVE_DYNTICK
-#else /* #ifdef CONFIG_NO_HZ */
-#define RCU_SIGNAL_INIT		RCU_FORCE_QS
-#endif /* #else #ifdef CONFIG_NO_HZ */
-
-#define RCU_JIFFIES_TILL_FORCE_QS	 3	/* for rsp->jiffies_force_qs */
-#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
-#define RCU_SECONDS_TILL_STALL_CHECK   (10 * HZ)  /* for rsp->jiffies_stall */
-#define RCU_SECONDS_TILL_STALL_RECHECK (30 * HZ)  /* for rsp->jiffies_stall */
-#define RCU_STALL_RAT_DELAY		2	  /* Allow other CPUs time */
-						  /*  to take at least one */
-						  /*  scheduling clock irq */
-						  /*  before ratting on them. */
-
-#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
-
-/*
- * RCU global state, including node hierarchy.  This hierarchy is
- * represented in "heap" form in a dense array.  The root (first level)
- * of the hierarchy is in ->node[0] (referenced by ->level[0]), the second
- * level in ->node[1] through ->node[m] (->node[1] referenced by ->level[1]),
- * and the third level in ->node[m+1] and following (->node[m+1] referenced
- * by ->level[2]).  The number of levels is determined by the number of
- * CPUs and by CONFIG_RCU_FANOUT.  Small systems will have a "hierarchy"
- * consisting of a single rcu_node.
- */
-struct rcu_state {
-	struct rcu_node node[NUM_RCU_NODES];	/* Hierarchy. */
-	struct rcu_node *level[NUM_RCU_LVLS];	/* Hierarchy levels. */
-	u32 levelcnt[MAX_RCU_LVLS + 1];		/* # nodes in each level. */
-	u8 levelspread[NUM_RCU_LVLS];		/* kids/node in each level. */
-	struct rcu_data *rda[NR_CPUS];		/* array of rdp pointers. */
-
-	/* The following fields are guarded by the root rcu_node's lock. */
-
-	u8	signaled ____cacheline_internodealigned_in_smp;
-						/* Force QS state. */
-	long	gpnum;				/* Current gp number. */
-	long	completed;			/* # of last completed gp. */
-	spinlock_t onofflock;			/* exclude on/offline and */
-						/*  starting new GP. */
-	spinlock_t fqslock;			/* Only one task forcing */
-						/*  quiescent states. */
-	unsigned long jiffies_force_qs;		/* Time at which to invoke */
-						/*  force_quiescent_state(). */
-	unsigned long n_force_qs;		/* Number of calls to */
-						/*  force_quiescent_state(). */
-	unsigned long n_force_qs_lh;		/* ~Number of calls leaving */
-						/*  due to lock unavailable. */
-	unsigned long n_force_qs_ngp;		/* Number of calls leaving */
-						/*  due to no GP active. */
-#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
-	unsigned long gp_start;			/* Time at which GP started, */
-						/*  but in jiffies. */
-	unsigned long jiffies_stall;		/* Time at which to check */
-						/*  for CPU stalls. */
-#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
-#ifdef CONFIG_NO_HZ
-	long dynticks_completed;		/* Value of completed @ snap. */
-#endif /* #ifdef CONFIG_NO_HZ */
-};
+extern void rcu_sched_qs(int cpu);
+extern void rcu_bh_qs(int cpu);
+extern int rcu_cpu_notify(struct notifier_block *self,
+			  unsigned long action, void *hcpu);
+extern int rcu_needs_cpu(int cpu);
+extern int rcu_expedited_torture_stats(char *page);
 
-extern void rcu_qsctr_inc(int cpu);
-extern void rcu_bh_qsctr_inc(int cpu);
+#ifdef CONFIG_TREE_PREEMPT_RCU
 
-extern int rcu_pending(int cpu);
-extern int rcu_needs_cpu(int cpu);
+extern void __rcu_read_lock(void);
+extern void __rcu_read_unlock(void);
+extern void exit_rcu(void);
 
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
-extern struct lockdep_map rcu_lock_map;
-# define rcu_read_acquire()	\
-			lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
-# define rcu_read_release()	lock_release(&rcu_lock_map, 1, _THIS_IP_)
-#else
-# define rcu_read_acquire()	do { } while (0)
-# define rcu_read_release()	do { } while (0)
-#endif
+#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
 
 static inline void __rcu_read_lock(void)
 {
 	preempt_disable();
-	__acquire(RCU);
-	rcu_read_acquire();
 }
+
 static inline void __rcu_read_unlock(void)
 {
-	rcu_read_release();
-	__release(RCU);
 	preempt_enable();
 }
+
+#define __synchronize_sched() synchronize_rcu()
+
+static inline void exit_rcu(void)
+{
+}
+
+#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
+
 static inline void __rcu_read_lock_bh(void)
 {
 	local_bh_disable();
-	__acquire(RCU_BH);
-	rcu_read_acquire();
 }
 static inline void __rcu_read_unlock_bh(void)
 {
-	rcu_read_release();
-	__release(RCU_BH);
 	local_bh_enable();
 }
 
-#define __synchronize_sched() synchronize_rcu()
-
-#define call_rcu_sched(head, func) call_rcu(head, func)
+extern void call_rcu_sched(struct rcu_head *head,
+			   void (*func)(struct rcu_head *rcu));
+extern void synchronize_rcu_expedited(void);
 
-static inline void rcu_init_sched(void)
+static inline void synchronize_rcu_bh_expedited(void)
 {
+	synchronize_sched_expedited();
 }
 
 extern void __rcu_init(void);
 extern void rcu_check_callbacks(int cpu, int user);
-extern void rcu_restart_cpu(int cpu);
 
 extern long rcu_batches_completed(void);
 extern long rcu_batches_completed_bh(void);
+extern long rcu_batches_completed_sched(void);
 
 #ifdef CONFIG_NO_HZ
 void rcu_enter_nohz(void);
@@ -309,7 +102,7 @@ static inline void rcu_exit_nohz(void)
 }
 #endif /* CONFIG_NO_HZ */
 
-/* A context switch is a grace period for rcutree. */
+/* A context switch is a grace period for RCU-sched and RCU-bh. */
 static inline int rcu_blocking_is_gp(void)
 {
 	return num_online_cpus() == 1;