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/*
* Read-Copy Update mechanism for mutual exclusion (tree-based version)
* Internal non-public definitions.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright IBM Corporation, 2008
*
* Author: Ingo Molnar <mingo@elte.hu>
* Paul E. McKenney <paulmck@linux.vnet.ibm.com>
*/
#include <linux/cache.h>
#include <linux/spinlock.h>
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/seqlock.h>
#define MAX_RCU_LVLS 4
#if CONFIG_RCU_FANOUT > 16
#define RCU_FANOUT_LEAF 16
#else
#define RCU_FANOUT_LEAF (CONFIG_RCU_FANOUT)
#endif
#define RCU_FANOUT_1 (RCU_FANOUT_LEAF)
#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT)
#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT)
#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT)
#if NR_CPUS <= RCU_FANOUT_1
# 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
# define NUM_RCU_LVL_4 0
#elif NR_CPUS <= RCU_FANOUT_2
# define NUM_RCU_LVLS 2
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
# define NUM_RCU_LVL_2 (NR_CPUS)
# define NUM_RCU_LVL_3 0
# define NUM_RCU_LVL_4 0
#elif NR_CPUS <= RCU_FANOUT_3
# define NUM_RCU_LVLS 3
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
# define NUM_RCU_LVL_3 (NR_CPUS)
# define NUM_RCU_LVL_4 0
#elif NR_CPUS <= RCU_FANOUT_4
# define NUM_RCU_LVLS 4
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
# define NUM_RCU_LVL_4 (NR_CPUS)
#else
# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
#endif
#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4)
#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
struct rcu_dynticks {
long long dynticks_nesting;
int dynticks_nmi_nesting;
atomic_t dynticks;
};
#define RCU_KTHREAD_STOPPED 0
#define RCU_KTHREAD_RUNNING 1
#define RCU_KTHREAD_WAITING 2
#define RCU_KTHREAD_OFFCPU 3
#define RCU_KTHREAD_YIELDING 4
#define RCU_KTHREAD_MAX 4
struct rcu_node {
raw_spinlock_t lock;
unsigned long gpnum;
unsigned long completed;
unsigned long qsmask;
unsigned long expmask;
atomic_t wakemask;
unsigned long qsmaskinit;
unsigned long grpmask;
int grplo;
int grphi;
u8 grpnum;
u8 level;
struct rcu_node *parent;
struct list_head blkd_tasks;
struct list_head *gp_tasks;
struct list_head *exp_tasks;
#ifdef CONFIG_RCU_BOOST
struct list_head *boost_tasks;
unsigned long boost_time;
struct task_struct *boost_kthread_task;
unsigned int boost_kthread_status;
unsigned long n_tasks_boosted;
unsigned long n_exp_boosts;
unsigned long n_normal_boosts;
unsigned long n_balk_blkd_tasks;
unsigned long n_balk_exp_gp_tasks;
unsigned long n_balk_boost_tasks;
unsigned long n_balk_notblocked;
unsigned long n_balk_notyet;
unsigned long n_balk_nos;
#endif
struct task_struct *node_kthread_task;
unsigned int node_kthread_status;
} ____cacheline_internodealigned_in_smp;
#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_nonleaf_node_breadth_first(rsp, rnp) \
for ((rnp) = &(rsp)->node[0]; \
(rnp) < (rsp)->level[NUM_RCU_LVLS - 1]; (rnp)++)
#define rcu_for_each_leaf_node(rsp, rnp) \
for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
(rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
#define RCU_DONE_TAIL 0
#define RCU_WAIT_TAIL 1
#define RCU_NEXT_READY_TAIL 2
#define RCU_NEXT_TAIL 3
#define RCU_NEXT_SIZE 4
struct rcu_data {
unsigned long completed;
unsigned long gpnum;
unsigned long passed_quiesce_gpnum;
bool passed_quiesce;
bool qs_pending;
bool beenonline;
bool preemptible;
struct rcu_node *mynode;
unsigned long grpmask;
#ifdef CONFIG_RCU_CPU_STALL_INFO
unsigned long ticks_this_gp;
#endif
struct rcu_head *nxtlist;
struct rcu_head **nxttail[RCU_NEXT_SIZE];
long qlen_lazy;
long qlen;
long qlen_last_fqs_check;
unsigned long n_cbs_invoked;
unsigned long n_cbs_orphaned;
unsigned long n_cbs_adopted;
unsigned long n_force_qs_snap;
long blimit;
struct rcu_dynticks *dynticks;
int dynticks_snap;
unsigned long dynticks_fqs;
unsigned long offline_fqs;
unsigned long n_rcu_pending;
unsigned long n_rp_qs_pending;
unsigned long n_rp_report_qs;
unsigned long n_rp_cb_ready;
unsigned long n_rp_cpu_needs_gp;
unsigned long n_rp_gp_completed;
unsigned long n_rp_gp_started;
unsigned long n_rp_need_fqs;
unsigned long n_rp_need_nothing;
int cpu;
struct rcu_state *rsp;
};
#define RCU_GP_IDLE 0
#define RCU_GP_INIT 1
#define RCU_SAVE_DYNTICK 2
#define RCU_FORCE_QS 3
#define RCU_SIGNAL_INIT RCU_SAVE_DYNTICK
#define RCU_JIFFIES_TILL_FORCE_QS 3
#ifdef CONFIG_PROVE_RCU
#define RCU_STALL_DELAY_DELTA (5 * HZ)
#else
#define RCU_STALL_DELAY_DELTA 0
#endif
#define RCU_STALL_RAT_DELAY 2
#define rcu_wait(cond) \
do { \
for (;;) { \
set_current_state(TASK_INTERRUPTIBLE); \
if (cond) \
break; \
schedule(); \
} \
__set_current_state(TASK_RUNNING); \
} while (0)
struct rcu_state {
struct rcu_node node[NUM_RCU_NODES];
struct rcu_node *level[NUM_RCU_LVLS];
u32 levelcnt[MAX_RCU_LVLS + 1];
u8 levelspread[NUM_RCU_LVLS];
struct rcu_data __percpu *rda;
u8 fqs_state ____cacheline_internodealigned_in_smp;
u8 fqs_active;
u8 fqs_need_gp;
u8 boost;
unsigned long gpnum;
unsigned long completed;
raw_spinlock_t onofflock;
raw_spinlock_t fqslock;
unsigned long jiffies_force_qs;
unsigned long n_force_qs;
unsigned long n_force_qs_lh;
unsigned long n_force_qs_ngp;
unsigned long gp_start;
unsigned long jiffies_stall;
unsigned long gp_max;
char *name;
};
#define RCU_OFL_TASKS_NORM_GP 0x1
#define RCU_OFL_TASKS_EXP_GP 0x2
extern struct rcu_state rcu_sched_state;
DECLARE_PER_CPU(struct rcu_data, rcu_sched_data);
extern struct rcu_state rcu_bh_state;
DECLARE_PER_CPU(struct rcu_data, rcu_bh_data);
#ifdef CONFIG_TREE_PREEMPT_RCU
extern struct rcu_state rcu_preempt_state;
DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
#endif
#ifdef CONFIG_RCU_BOOST
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
DECLARE_PER_CPU(int, rcu_cpu_kthread_cpu);
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_loops);
DECLARE_PER_CPU(char, rcu_cpu_has_work);
#endif
#ifndef RCU_TREE_NONCORE
static void rcu_bootup_announce(void);
long rcu_batches_completed(void);
static void rcu_preempt_note_context_switch(int cpu);
static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
unsigned long flags);
static void rcu_stop_cpu_kthread(int cpu);
#endif
static void rcu_print_detail_task_stall(struct rcu_state *rsp);
static int rcu_print_task_stall(struct rcu_node *rnp);
static void rcu_preempt_stall_reset(void);
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
struct rcu_node *rnp,
struct rcu_data *rdp);
#endif
static void rcu_preempt_cleanup_dead_cpu(int 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));
#if defined(CONFIG_HOTPLUG_CPU) || defined(CONFIG_TREE_PREEMPT_RCU)
static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
bool wake);
#endif
static int rcu_preempt_pending(int cpu);
static int rcu_preempt_cpu_has_callbacks(int cpu);
static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
static void rcu_preempt_cleanup_dying_cpu(void);
static void __init __rcu_init_preempt(void);
static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags);
static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
static void invoke_rcu_callbacks_kthread(void);
static bool rcu_is_callbacks_kthread(void);
#ifdef CONFIG_RCU_BOOST
static void rcu_preempt_do_callbacks(void);
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp,
cpumask_var_t cm);
static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
struct rcu_node *rnp,
int rnp_index);
static void invoke_rcu_node_kthread(struct rcu_node *rnp);
static void rcu_yield(void (*f)(unsigned long), unsigned long arg);
#endif
static void rcu_cpu_kthread_setrt(int cpu, int to_rt);
static void __cpuinit rcu_prepare_kthreads(int cpu);
static void rcu_prepare_for_idle_init(int cpu);
static void rcu_cleanup_after_idle(int cpu);
static void rcu_prepare_for_idle(int cpu);
static void print_cpu_stall_info_begin(void);
static void print_cpu_stall_info(struct rcu_state *rsp, int cpu);
static void print_cpu_stall_info_end(void);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
static void increment_cpu_stall_ticks(void);
#endif
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