Update Linux to v5.4.2
Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 4e74df7..c612f30 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -1,25 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
/*
* 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, you can access it online at
- * http://www.gnu.org/licenses/gpl-2.0.html.
- *
* Copyright IBM Corporation, 2008
*
* Author: Ingo Molnar <mingo@elte.hu>
- * Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ * Paul E. McKenney <paulmck@linux.ibm.com>
*/
#include <linux/cache.h>
@@ -34,34 +21,8 @@
#include "rcu_segcblist.h"
-/*
- * Dynticks per-CPU state.
- */
-struct rcu_dynticks {
- long dynticks_nesting; /* Track process nesting level. */
- long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */
- atomic_t dynticks; /* Even value for idle, else odd. */
- bool rcu_need_heavy_qs; /* GP old, need heavy quiescent state. */
- unsigned long rcu_qs_ctr; /* Light universal quiescent state ctr. */
- bool rcu_urgent_qs; /* GP old need light quiescent state. */
-#ifdef CONFIG_RCU_FAST_NO_HZ
- bool all_lazy; /* Are all CPU's CBs lazy? */
- unsigned long nonlazy_posted;
- /* # times non-lazy CBs posted to CPU. */
- unsigned long nonlazy_posted_snap;
- /* idle-period nonlazy_posted snapshot. */
- unsigned long last_accelerate;
- /* Last jiffy CBs were accelerated. */
- unsigned long last_advance_all;
- /* Last jiffy CBs were all advanced. */
- int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
-#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
-};
-
/* Communicate arguments to a workqueue handler. */
struct rcu_exp_work {
- smp_call_func_t rew_func;
- struct rcu_state *rew_rsp;
unsigned long rew_s;
struct work_struct rew_work;
};
@@ -82,7 +43,7 @@
/* some rcu_state fields as well as */
/* following. */
unsigned long gp_seq; /* Track rsp->rcu_gp_seq. */
- unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed. */
+ unsigned long gp_seq_needed; /* Track furthest future GP request. */
unsigned long completedqs; /* All QSes done for this node. */
unsigned long qsmask; /* CPUs or groups that need to switch in */
/* order for current grace period to proceed.*/
@@ -170,7 +131,7 @@
* are indexed relative to this interval rather than the global CPU ID space.
* This generates the bit for a CPU in node-local masks.
*/
-#define leaf_node_cpu_bit(rnp, cpu) (1UL << ((cpu) - (rnp)->grplo))
+#define leaf_node_cpu_bit(rnp, cpu) (BIT((cpu) - (rnp)->grplo))
/*
* Union to allow "aggregate OR" operation on the need for a quiescent
@@ -188,19 +149,20 @@
struct rcu_data {
/* 1) quiescent-state and grace-period handling : */
unsigned long gp_seq; /* Track rsp->rcu_gp_seq counter. */
- unsigned long gp_seq_needed; /* Track rsp->rcu_gp_seq_needed ctr. */
- unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */
- /* for rcu_all_qs() invocations. */
+ unsigned long gp_seq_needed; /* Track furthest future GP request. */
union rcu_noqs cpu_no_qs; /* No QSes yet for this CPU. */
bool core_needs_qs; /* Core waits for quiesc state. */
bool beenonline; /* CPU online at least once. */
bool gpwrap; /* Possible ->gp_seq wrap. */
+ bool exp_deferred_qs; /* This CPU awaiting a deferred QS? */
struct rcu_node *mynode; /* This CPU's leaf of hierarchy */
unsigned long grpmask; /* Mask to apply to leaf qsmask. */
unsigned long ticks_this_gp; /* The number of scheduling-clock */
/* ticks this CPU has handled */
/* during and after the last grace */
/* period it is aware of. */
+ struct irq_work defer_qs_iw; /* Obtain later scheduler attention. */
+ bool defer_qs_iw_pending; /* Scheduler attention pending? */
/* 2) batch handling */
struct rcu_segcblist cblist; /* Segmented callback list, with */
@@ -213,49 +175,65 @@
long blimit; /* Upper limit on a processed batch */
/* 3) dynticks interface. */
- struct rcu_dynticks *dynticks; /* Shared per-CPU dynticks state. */
int dynticks_snap; /* Per-GP tracking for dynticks. */
-
- /* 4) reasons this CPU needed to be kicked by force_quiescent_state */
- unsigned long dynticks_fqs; /* Kicked due to dynticks idle. */
- unsigned long cond_resched_completed;
- /* Grace period that needs help */
- /* from cond_resched(). */
-
- /* 5) _rcu_barrier(), OOM callbacks, and expediting. */
- struct rcu_head barrier_head;
+ long dynticks_nesting; /* Track process nesting level. */
+ long dynticks_nmi_nesting; /* Track irq/NMI nesting level. */
+ atomic_t dynticks; /* Even value for idle, else odd. */
+ bool rcu_need_heavy_qs; /* GP old, so heavy quiescent state! */
+ bool rcu_urgent_qs; /* GP old need light quiescent state. */
#ifdef CONFIG_RCU_FAST_NO_HZ
- struct rcu_head oom_head;
+ bool all_lazy; /* All CPU's CBs lazy at idle start? */
+ unsigned long last_accelerate; /* Last jiffy CBs were accelerated. */
+ unsigned long last_advance_all; /* Last jiffy CBs were all advanced. */
+ int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
+
+ /* 4) rcu_barrier(), OOM callbacks, and expediting. */
+ struct rcu_head barrier_head;
int exp_dynticks_snap; /* Double-check need for IPI. */
- /* 6) Callback offloading. */
+ /* 5) Callback offloading. */
#ifdef CONFIG_RCU_NOCB_CPU
- struct rcu_head *nocb_head; /* CBs waiting for kthread. */
- struct rcu_head **nocb_tail;
- atomic_long_t nocb_q_count; /* # CBs waiting for nocb */
- atomic_long_t nocb_q_count_lazy; /* invocation (all stages). */
- struct rcu_head *nocb_follower_head; /* CBs ready to invoke. */
- struct rcu_head **nocb_follower_tail;
- struct swait_queue_head nocb_wq; /* For nocb kthreads to sleep on. */
- struct task_struct *nocb_kthread;
+ struct swait_queue_head nocb_cb_wq; /* For nocb kthreads to sleep on. */
+ struct task_struct *nocb_gp_kthread;
raw_spinlock_t nocb_lock; /* Guard following pair of fields. */
+ atomic_t nocb_lock_contended; /* Contention experienced. */
int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */
struct timer_list nocb_timer; /* Enforce finite deferral. */
+ unsigned long nocb_gp_adv_time; /* Last call_rcu() CB adv (jiffies). */
- /* The following fields are used by the leader, hence own cacheline. */
- struct rcu_head *nocb_gp_head ____cacheline_internodealigned_in_smp;
- /* CBs waiting for GP. */
- struct rcu_head **nocb_gp_tail;
- bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */
- struct rcu_data *nocb_next_follower;
- /* Next follower in wakeup chain. */
+ /* The following fields are used by call_rcu, hence own cacheline. */
+ raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp;
+ struct rcu_cblist nocb_bypass; /* Lock-contention-bypass CB list. */
+ unsigned long nocb_bypass_first; /* Time (jiffies) of first enqueue. */
+ unsigned long nocb_nobypass_last; /* Last ->cblist enqueue (jiffies). */
+ int nocb_nobypass_count; /* # ->cblist enqueues at ^^^ time. */
- /* The following fields are used by the follower, hence new cachline. */
- struct rcu_data *nocb_leader ____cacheline_internodealigned_in_smp;
- /* Leader CPU takes GP-end wakeups. */
+ /* The following fields are used by GP kthread, hence own cacheline. */
+ raw_spinlock_t nocb_gp_lock ____cacheline_internodealigned_in_smp;
+ struct timer_list nocb_bypass_timer; /* Force nocb_bypass flush. */
+ u8 nocb_gp_sleep; /* Is the nocb GP thread asleep? */
+ u8 nocb_gp_bypass; /* Found a bypass on last scan? */
+ u8 nocb_gp_gp; /* GP to wait for on last scan? */
+ unsigned long nocb_gp_seq; /* If so, ->gp_seq to wait for. */
+ unsigned long nocb_gp_loops; /* # passes through wait code. */
+ struct swait_queue_head nocb_gp_wq; /* For nocb kthreads to sleep on. */
+ bool nocb_cb_sleep; /* Is the nocb CB thread asleep? */
+ struct task_struct *nocb_cb_kthread;
+ struct rcu_data *nocb_next_cb_rdp;
+ /* Next rcu_data in wakeup chain. */
+
+ /* The following fields are used by CB kthread, hence new cacheline. */
+ struct rcu_data *nocb_gp_rdp ____cacheline_internodealigned_in_smp;
+ /* GP rdp takes GP-end wakeups. */
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
+ /* 6) RCU priority boosting. */
+ struct task_struct *rcu_cpu_kthread_task;
+ /* rcuc per-CPU kthread or NULL. */
+ unsigned int rcu_cpu_kthread_status;
+ char rcu_cpu_has_work;
+
/* 7) Diagnostic data, including RCU CPU stall warnings. */
unsigned int softirq_snap; /* Snapshot of softirq activity. */
/* ->rcu_iw* fields protected by leaf rcu_node ->lock. */
@@ -266,9 +244,9 @@
short rcu_ofl_gp_flags; /* ->gp_flags at last offline. */
unsigned long rcu_onl_gp_seq; /* ->gp_seq at last online. */
short rcu_onl_gp_flags; /* ->gp_flags at last online. */
+ unsigned long last_fqs_resched; /* Time of last rcu_resched(). */
int cpu;
- struct rcu_state *rsp;
};
/* Values for nocb_defer_wakeup field in struct rcu_data. */
@@ -314,8 +292,6 @@
struct rcu_node *level[RCU_NUM_LVLS + 1];
/* Hierarchy levels (+1 to */
/* shut bogus gcc warning) */
- struct rcu_data __percpu *rda; /* pointer of percu rcu_data. */
- call_rcu_func_t call; /* call_rcu() flavor. */
int ncpus; /* # CPUs seen so far. */
/* The following fields are guarded by the root rcu_node's lock. */
@@ -327,6 +303,8 @@
struct swait_queue_head gp_wq; /* Where GP task waits. */
short gp_flags; /* Commands for GP task. */
short gp_state; /* GP kthread sleep state. */
+ unsigned long gp_wake_time; /* Last GP kthread wake. */
+ unsigned long gp_wake_seq; /* ->gp_seq at ^^^. */
/* End of fields guarded by root rcu_node's lock. */
@@ -334,7 +312,7 @@
atomic_t barrier_cpu_count; /* # CPUs waiting on. */
struct completion barrier_completion; /* Wake at barrier end. */
unsigned long barrier_sequence; /* ++ at start and end of */
- /* _rcu_barrier(). */
+ /* rcu_barrier(). */
/* End of fields guarded by barrier_mutex. */
struct mutex exp_mutex; /* Serialize expedited GP. */
@@ -352,6 +330,8 @@
/* force_quiescent_state(). */
unsigned long gp_start; /* Time at which GP started, */
/* but in jiffies. */
+ unsigned long gp_end; /* Time last GP ended, again */
+ /* in jiffies. */
unsigned long gp_activity; /* Time of last GP kthread */
/* activity in jiffies. */
unsigned long gp_req_activity; /* Time of last GP request */
@@ -366,9 +346,8 @@
/* jiffies. */
const char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
- struct list_head flavors; /* List of RCU flavors. */
- spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
+ raw_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
/* Synchronize offline with */
/* GP pre-initialization. */
};
@@ -388,7 +367,6 @@
#define RCU_GP_CLEANUP 7 /* Grace-period cleanup started. */
#define RCU_GP_CLEANED 8 /* Grace-period cleanup complete. */
-#ifndef RCU_TREE_NONCORE
static const char * const gp_state_names[] = {
"RCU_GP_IDLE",
"RCU_GP_WAIT_GPS",
@@ -400,101 +378,97 @@
"RCU_GP_CLEANUP",
"RCU_GP_CLEANED",
};
-#endif /* #ifndef RCU_TREE_NONCORE */
-
-extern struct list_head rcu_struct_flavors;
-
-/* Sequence through rcu_state structures for each RCU flavor. */
-#define for_each_rcu_flavor(rsp) \
- list_for_each_entry((rsp), &rcu_struct_flavors, flavors)
/*
- * RCU implementation internal declarations:
+ * In order to export the rcu_state name to the tracing tools, it
+ * needs to be added in the __tracepoint_string section.
+ * This requires defining a separate variable tp_<sname>_varname
+ * that points to the string being used, and this will allow
+ * the tracing userspace tools to be able to decipher the string
+ * address to the matching string.
*/
-extern struct rcu_state rcu_sched_state;
-
-extern struct rcu_state rcu_bh_state;
-
#ifdef CONFIG_PREEMPT_RCU
-extern struct rcu_state rcu_preempt_state;
-#endif /* #ifdef CONFIG_PREEMPT_RCU */
+#define RCU_ABBR 'p'
+#define RCU_NAME_RAW "rcu_preempt"
+#else /* #ifdef CONFIG_PREEMPT_RCU */
+#define RCU_ABBR 's'
+#define RCU_NAME_RAW "rcu_sched"
+#endif /* #else #ifdef CONFIG_PREEMPT_RCU */
+#ifndef CONFIG_TRACING
+#define RCU_NAME RCU_NAME_RAW
+#else /* #ifdef CONFIG_TRACING */
+static char rcu_name[] = RCU_NAME_RAW;
+static const char *tp_rcu_varname __used __tracepoint_string = rcu_name;
+#define RCU_NAME rcu_name
+#endif /* #else #ifdef CONFIG_TRACING */
-int rcu_dynticks_snap(struct rcu_dynticks *rdtp);
+int rcu_dynticks_snap(struct rcu_data *rdp);
-#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 /* #ifdef CONFIG_RCU_BOOST */
-
-#ifndef RCU_TREE_NONCORE
-
-/* Forward declarations for rcutree_plugin.h */
+/* Forward declarations for tree_plugin.h */
static void rcu_bootup_announce(void);
-static void rcu_preempt_note_context_switch(bool preempt);
+static void rcu_qs(void);
static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
-static void rcu_print_detail_task_stall(struct rcu_state *rsp);
-static int rcu_print_task_stall(struct rcu_node *rnp);
static int rcu_print_task_exp_stall(struct rcu_node *rnp);
-static void rcu_preempt_check_blocked_tasks(struct rcu_state *rsp,
- struct rcu_node *rnp);
-static void rcu_preempt_check_callbacks(void);
+static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
+static void rcu_flavor_sched_clock_irq(int user);
void call_rcu(struct rcu_head *head, rcu_callback_t func);
-static void __init __rcu_init_preempt(void);
-static void dump_blkd_tasks(struct rcu_state *rsp, struct rcu_node *rnp,
- int ncheck);
+static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck);
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 int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
- struct rcu_node *rnp);
-#endif /* #ifdef CONFIG_RCU_BOOST */
+static void rcu_cpu_kthread_setup(unsigned int cpu);
static void __init rcu_spawn_boost_kthreads(void);
static void rcu_prepare_kthreads(int cpu);
static void rcu_cleanup_after_idle(void);
static void rcu_prepare_for_idle(void);
-static void rcu_idle_count_callbacks_posted(void);
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
-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 bool rcu_preempt_need_deferred_qs(struct task_struct *t);
+static void rcu_preempt_deferred_qs(struct task_struct *t);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
-static void increment_cpu_stall_ticks(void);
-static bool rcu_nocb_cpu_needs_barrier(struct rcu_state *rsp, int cpu);
static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
static void rcu_init_one_nocb(struct rcu_node *rnp);
-static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
- bool lazy, unsigned long flags);
-static bool rcu_nocb_adopt_orphan_cbs(struct rcu_data *my_rdp,
- struct rcu_data *rdp,
- unsigned long flags);
+static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+ unsigned long j);
+static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
+ bool *was_alldone, unsigned long flags);
+static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_empty,
+ unsigned long flags);
static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp);
static void do_nocb_deferred_wakeup(struct rcu_data *rdp);
static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
-static void rcu_spawn_all_nocb_kthreads(int cpu);
+static void rcu_spawn_cpu_nocb_kthread(int cpu);
static void __init rcu_spawn_nocb_kthreads(void);
+static void show_rcu_nocb_state(struct rcu_data *rdp);
+static void rcu_nocb_lock(struct rcu_data *rdp);
+static void rcu_nocb_unlock(struct rcu_data *rdp);
+static void rcu_nocb_unlock_irqrestore(struct rcu_data *rdp,
+ unsigned long flags);
+static void rcu_lockdep_assert_cblist_protected(struct rcu_data *rdp);
#ifdef CONFIG_RCU_NOCB_CPU
-static void __init rcu_organize_nocb_kthreads(struct rcu_state *rsp);
-#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
-static bool init_nocb_callback_list(struct rcu_data *rdp);
+static void __init rcu_organize_nocb_kthreads(void);
+#define rcu_nocb_lock_irqsave(rdp, flags) \
+do { \
+ if (!rcu_segcblist_is_offloaded(&(rdp)->cblist)) \
+ local_irq_save(flags); \
+ else \
+ raw_spin_lock_irqsave(&(rdp)->nocb_lock, (flags)); \
+} while (0)
+#else /* #ifdef CONFIG_RCU_NOCB_CPU */
+#define rcu_nocb_lock_irqsave(rdp, flags) local_irq_save(flags)
+#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
+
static void rcu_bind_gp_kthread(void);
-static bool rcu_nohz_full_cpu(struct rcu_state *rsp);
+static bool rcu_nohz_full_cpu(void);
static void rcu_dynticks_task_enter(void);
static void rcu_dynticks_task_exit(void);
-#ifdef CONFIG_SRCU
-void srcu_online_cpu(unsigned int cpu);
-void srcu_offline_cpu(unsigned int cpu);
-#else /* #ifdef CONFIG_SRCU */
-void srcu_online_cpu(unsigned int cpu) { }
-void srcu_offline_cpu(unsigned int cpu) { }
-#endif /* #else #ifdef CONFIG_SRCU */
-
-#endif /* #ifndef RCU_TREE_NONCORE */
+/* Forward declarations for tree_stall.h */
+static void record_gp_stall_check_time(void);
+static void rcu_iw_handler(struct irq_work *iwp);
+static void check_cpu_stall(struct rcu_data *rdp);
+static void rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
+ const unsigned long gpssdelay);