Merge branches 'bitmaprange.2021.05.10c', 'doc.2021.05.10c', 'fixes.2021.05.13a', 'kvfree_rcu.2021.05.10c', 'mmdumpobj.2021.05.10c', 'nocb.2021.05.12a', 'srcu.2021.05.12a', 'tasks.2021.05.18a' and 'torture.2021.05.10c' into HEAD
bitmaprange.2021.05.10c: Allow "all" for bitmap ranges.
doc.2021.05.10c: Documentation updates.
fixes.2021.05.13a: Miscellaneous fixes.
kvfree_rcu.2021.05.10c: kvfree_rcu() updates.
mmdumpobj.2021.05.10c: mem_dump_obj() updates.
nocb.2021.05.12a: RCU NOCB CPU updates, including limited deoffloading.
srcu.2021.05.12a: SRCU updates.
tasks.2021.05.18a: Tasks-RCU updates.
torture.2021.05.10c: Torture-test updates.
diff --git a/Documentation/admin-guide/kernel-parameters.rst b/Documentation/admin-guide/kernel-parameters.rst
index 3996b54..01ba293 100644
--- a/Documentation/admin-guide/kernel-parameters.rst
+++ b/Documentation/admin-guide/kernel-parameters.rst
@@ -76,6 +76,11 @@
will also change. Use the same on a small 4 core system, and "16-N" becomes
"16-3" and now the same boot input will be flagged as invalid (start > end).
+The special case-tolerant group name "all" has a meaning of selecting all CPUs,
+so that "nohz_full=all" is the equivalent of "nohz_full=0-N".
+
+The semantics of "N" and "all" is supported on a level of bitmaps and holds for
+all users of bitmap_parse().
This document may not be entirely up to date and comprehensive. The command
"modinfo -p ${modulename}" shows a current list of all parameters of a loadable
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index cb89dbd..4405fd3 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4290,6 +4290,11 @@
whole algorithm to behave better in low memory
condition.
+ rcutree.rcu_delay_page_cache_fill_msec= [KNL]
+ Set the page-cache refill delay (in milliseconds)
+ in response to low-memory conditions. The range
+ of permitted values is in the range 0:100000.
+
rcutree.jiffies_till_first_fqs= [KNL]
Set delay from grace-period initialization to
first attempt to force quiescent states.
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 9455476..d9680b7 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -315,7 +315,7 @@
#define RCU_LOCKDEP_WARN(c, s) \
do { \
static bool __section(".data.unlikely") __warned; \
- if (debug_lockdep_rcu_enabled() && !__warned && (c)) { \
+ if ((c) && debug_lockdep_rcu_enabled() && !__warned) { \
__warned = true; \
lockdep_rcu_suspicious(__FILE__, __LINE__, s); \
} \
@@ -363,6 +363,20 @@
#define rcu_check_sparse(p, space)
#endif /* #else #ifdef __CHECKER__ */
+/**
+ * unrcu_pointer - mark a pointer as not being RCU protected
+ * @p: pointer needing to lose its __rcu property
+ *
+ * Converts @p from an __rcu pointer to a __kernel pointer.
+ * This allows an __rcu pointer to be used with xchg() and friends.
+ */
+#define unrcu_pointer(p) \
+({ \
+ typeof(*p) *_________p1 = (typeof(*p) *__force)(p); \
+ rcu_check_sparse(p, __rcu); \
+ ((typeof(*p) __force __kernel *)(_________p1)); \
+})
+
#define __rcu_access_pointer(p, space) \
({ \
typeof(*p) *_________p1 = (typeof(*p) *__force)READ_ONCE(p); \
@@ -518,7 +532,12 @@
* @p: The pointer to read, prior to dereferencing
* @c: The conditions under which the dereference will take place
*
- * This is the RCU-bh counterpart to rcu_dereference_check().
+ * This is the RCU-bh counterpart to rcu_dereference_check(). However,
+ * please note that starting in v5.0 kernels, vanilla RCU grace periods
+ * wait for local_bh_disable() regions of code in addition to regions of
+ * code demarked by rcu_read_lock() and rcu_read_unlock(). This means
+ * that synchronize_rcu(), call_rcu, and friends all take not only
+ * rcu_read_lock() but also rcu_read_lock_bh() into account.
*/
#define rcu_dereference_bh_check(p, c) \
__rcu_dereference_check((p), (c) || rcu_read_lock_bh_held(), __rcu)
@@ -529,6 +548,11 @@
* @c: The conditions under which the dereference will take place
*
* This is the RCU-sched counterpart to rcu_dereference_check().
+ * However, please note that starting in v5.0 kernels, vanilla RCU grace
+ * periods wait for preempt_disable() regions of code in addition to
+ * regions of code demarked by rcu_read_lock() and rcu_read_unlock().
+ * This means that synchronize_rcu(), call_rcu, and friends all take not
+ * only rcu_read_lock() but also rcu_read_lock_sched() into account.
*/
#define rcu_dereference_sched_check(p, c) \
__rcu_dereference_check((p), (c) || rcu_read_lock_sched_held(), \
@@ -620,6 +644,12 @@
* sections, invocation of the corresponding RCU callback is deferred
* until after the all the other CPUs exit their critical sections.
*
+ * In v5.0 and later kernels, synchronize_rcu() and call_rcu() also
+ * wait for regions of code with preemption disabled, including regions of
+ * code with interrupts or softirqs disabled. In pre-v5.0 kernels, which
+ * define synchronize_sched(), only code enclosed within rcu_read_lock()
+ * and rcu_read_unlock() are guaranteed to be waited for.
+ *
* Note, however, that RCU callbacks are permitted to run concurrently
* with new RCU read-side critical sections. One way that this can happen
* is via the following sequence of events: (1) CPU 0 enters an RCU
@@ -672,33 +702,12 @@
/**
* rcu_read_unlock() - marks the end of an RCU read-side critical section.
*
- * In most situations, rcu_read_unlock() is immune from deadlock.
- * However, in kernels built with CONFIG_RCU_BOOST, rcu_read_unlock()
- * is responsible for deboosting, which it does via rt_mutex_unlock().
- * Unfortunately, this function acquires the scheduler's runqueue and
- * priority-inheritance spinlocks. This means that deadlock could result
- * if the caller of rcu_read_unlock() already holds one of these locks or
- * any lock that is ever acquired while holding them.
- *
- * That said, RCU readers are never priority boosted unless they were
- * preempted. Therefore, one way to avoid deadlock is to make sure
- * that preemption never happens within any RCU read-side critical
- * section whose outermost rcu_read_unlock() is called with one of
- * rt_mutex_unlock()'s locks held. Such preemption can be avoided in
- * a number of ways, for example, by invoking preempt_disable() before
- * critical section's outermost rcu_read_lock().
- *
- * Given that the set of locks acquired by rt_mutex_unlock() might change
- * at any time, a somewhat more future-proofed approach is to make sure
- * that that preemption never happens within any RCU read-side critical
- * section whose outermost rcu_read_unlock() is called with irqs disabled.
- * This approach relies on the fact that rt_mutex_unlock() currently only
- * acquires irq-disabled locks.
- *
- * The second of these two approaches is best in most situations,
- * however, the first approach can also be useful, at least to those
- * developers willing to keep abreast of the set of locks acquired by
- * rt_mutex_unlock().
+ * In almost all situations, rcu_read_unlock() is immune from deadlock.
+ * In recent kernels that have consolidated synchronize_sched() and
+ * synchronize_rcu_bh() into synchronize_rcu(), this deadlock immunity
+ * also extends to the scheduler's runqueue and priority-inheritance
+ * spinlocks, courtesy of the quiescent-state deferral that is carried
+ * out when rcu_read_unlock() is invoked with interrupts disabled.
*
* See rcu_read_lock() for more information.
*/
@@ -714,9 +723,11 @@
/**
* rcu_read_lock_bh() - mark the beginning of an RCU-bh critical section
*
- * This is equivalent of rcu_read_lock(), but also disables softirqs.
- * Note that anything else that disables softirqs can also serve as
- * an RCU read-side critical section.
+ * This is equivalent to rcu_read_lock(), but also disables softirqs.
+ * Note that anything else that disables softirqs can also serve as an RCU
+ * read-side critical section. However, please note that this equivalence
+ * applies only to v5.0 and later. Before v5.0, rcu_read_lock() and
+ * rcu_read_lock_bh() were unrelated.
*
* Note that rcu_read_lock_bh() and the matching rcu_read_unlock_bh()
* must occur in the same context, for example, it is illegal to invoke
@@ -749,9 +760,12 @@
/**
* rcu_read_lock_sched() - mark the beginning of a RCU-sched critical section
*
- * This is equivalent of rcu_read_lock(), but disables preemption.
- * Read-side critical sections can also be introduced by anything else
- * that disables preemption, including local_irq_disable() and friends.
+ * This is equivalent to rcu_read_lock(), but also disables preemption.
+ * Read-side critical sections can also be introduced by anything else that
+ * disables preemption, including local_irq_disable() and friends. However,
+ * please note that the equivalence to rcu_read_lock() applies only to
+ * v5.0 and later. Before v5.0, rcu_read_lock() and rcu_read_lock_sched()
+ * were unrelated.
*
* Note that rcu_read_lock_sched() and the matching rcu_read_unlock_sched()
* must occur in the same context, for example, it is illegal to invoke
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 35e0be3..953e70f 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -86,7 +86,6 @@
static inline void rcu_irq_exit_irqson(void) { }
static inline void rcu_irq_enter_irqson(void) { }
static inline void rcu_irq_exit(void) { }
-static inline void rcu_irq_exit_preempt(void) { }
static inline void rcu_irq_exit_check_preempt(void) { }
#define rcu_is_idle_cpu(cpu) \
(is_idle_task(current) && !in_nmi() && !in_irq() && !in_serving_softirq())
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index b89b541..53209d6 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -49,7 +49,6 @@
void rcu_idle_exit(void);
void rcu_irq_enter(void);
void rcu_irq_exit(void);
-void rcu_irq_exit_preempt(void);
void rcu_irq_enter_irqson(void);
void rcu_irq_exit_irqson(void);
bool rcu_is_idle_cpu(int cpu);
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index a0895bb..e6011a9 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -64,6 +64,12 @@
unsigned long start_poll_synchronize_srcu(struct srcu_struct *ssp);
bool poll_state_synchronize_srcu(struct srcu_struct *ssp, unsigned long cookie);
+#ifdef CONFIG_SRCU
+void srcu_init(void);
+#else /* #ifdef CONFIG_SRCU */
+static inline void srcu_init(void) { }
+#endif /* #else #ifdef CONFIG_SRCU */
+
#ifdef CONFIG_DEBUG_LOCK_ALLOC
/**
diff --git a/include/linux/srcutree.h b/include/linux/srcutree.h
index 9cfcc8a..cb1f435 100644
--- a/include/linux/srcutree.h
+++ b/include/linux/srcutree.h
@@ -82,9 +82,7 @@
/* callback for the barrier */
/* operation. */
struct delayed_work work;
-#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
-#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
};
/* Values for state variable (bottom bits of ->srcu_gp_seq). */
diff --git a/include/linux/timer.h b/include/linux/timer.h
index 4118a97..fda13c9 100644
--- a/include/linux/timer.h
+++ b/include/linux/timer.h
@@ -192,8 +192,6 @@
#define del_singleshot_timer_sync(t) del_timer_sync(t)
-extern bool timer_curr_running(struct timer_list *timer);
-
extern void init_timers(void);
struct hrtimer;
extern enum hrtimer_restart it_real_fn(struct hrtimer *);
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 6768b64..670e417 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -278,6 +278,7 @@
* "WakeNot": Don't wake rcuo kthread.
* "WakeNotPoll": Don't wake rcuo kthread because it is polling.
* "WakeOvfIsDeferred": Wake rcuo kthread later, CB list is huge.
+ * "WakeBypassIsDeferred": Wake rcuo kthread later, bypass list is contended.
* "WokeEmpty": rcuo CB kthread woke to find empty list.
*/
TRACE_EVENT_RCU(rcu_nocb_wake,
diff --git a/init/main.c b/init/main.c
index eb01e12..7b6f49c 100644
--- a/init/main.c
+++ b/init/main.c
@@ -42,6 +42,7 @@
#include <linux/profile.h>
#include <linux/kfence.h>
#include <linux/rcupdate.h>
+#include <linux/srcu.h>
#include <linux/moduleparam.h>
#include <linux/kallsyms.h>
#include <linux/writeback.h>
@@ -979,6 +980,7 @@
tick_init();
rcu_init_nohz();
init_timers();
+ srcu_init();
hrtimers_init();
softirq_init();
timekeeping_init();
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 48d736a..d6c3c98 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -6393,6 +6393,7 @@
void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
{
struct task_struct *curr = current;
+ int dl = READ_ONCE(debug_locks);
/* Note: the following can be executed concurrently, so be careful. */
pr_warn("\n");
@@ -6402,11 +6403,12 @@
pr_warn("-----------------------------\n");
pr_warn("%s:%d %s!\n", file, line, s);
pr_warn("\nother info that might help us debug this:\n\n");
- pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
+ pr_warn("\n%srcu_scheduler_active = %d, debug_locks = %d\n%s",
!rcu_lockdep_current_cpu_online()
? "RCU used illegally from offline CPU!\n"
: "",
- rcu_scheduler_active, debug_locks);
+ rcu_scheduler_active, dl,
+ dl ? "" : "Possible false positive due to lockdep disabling via debug_locks = 0\n");
/*
* If a CPU is in the RCU-free window in idle (ie: in the section
diff --git a/kernel/rcu/Kconfig.debug b/kernel/rcu/Kconfig.debug
index 1942c1f..4fd6499 100644
--- a/kernel/rcu/Kconfig.debug
+++ b/kernel/rcu/Kconfig.debug
@@ -116,7 +116,7 @@
config RCU_STRICT_GRACE_PERIOD
bool "Provide debug RCU implementation with short grace periods"
- depends on DEBUG_KERNEL && RCU_EXPERT
+ depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4
default n
select PREEMPT_COUNT if PREEMPT=n
help
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h
index bf0827d..24b5f2c 100644
--- a/kernel/rcu/rcu.h
+++ b/kernel/rcu/rcu.h
@@ -308,6 +308,8 @@
}
}
+extern void rcu_init_geometry(void);
+
/* Returns a pointer to the first leaf rcu_node structure. */
#define rcu_first_leaf_node() (rcu_state.level[rcu_num_lvls - 1])
@@ -422,12 +424,6 @@
#endif /* #if defined(CONFIG_SRCU) || !defined(CONFIG_TINY_RCU) */
-#ifdef CONFIG_SRCU
-void srcu_init(void);
-#else /* #ifdef CONFIG_SRCU */
-static inline void srcu_init(void) { }
-#endif /* #else #ifdef CONFIG_SRCU */
-
#ifdef CONFIG_TINY_RCU
/* Tiny RCU doesn't expedite, as its purpose in life is instead to be tiny. */
static inline bool rcu_gp_is_normal(void) { return true; }
@@ -441,7 +437,11 @@
void rcu_expedite_gp(void);
void rcu_unexpedite_gp(void);
void rcupdate_announce_bootup_oddness(void);
+#ifdef CONFIG_TASKS_RCU_GENERIC
void show_rcu_tasks_gp_kthreads(void);
+#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
+static inline void show_rcu_tasks_gp_kthreads(void) {}
+#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
void rcu_request_urgent_qs_task(struct task_struct *t);
#endif /* #else #ifdef CONFIG_TINY_RCU */
@@ -519,6 +519,7 @@
static inline unsigned long
srcu_batches_completed(struct srcu_struct *sp) { return 0; }
static inline void rcu_force_quiescent_state(void) { }
+static inline bool rcu_check_boost_fail(unsigned long gp_state, int *cpup) { return true; }
static inline void show_rcu_gp_kthreads(void) { }
static inline int rcu_get_gp_kthreads_prio(void) { return 0; }
static inline void rcu_fwd_progress_check(unsigned long j) { }
@@ -527,6 +528,7 @@
unsigned long rcu_get_gp_seq(void);
unsigned long rcu_exp_batches_completed(void);
unsigned long srcu_batches_completed(struct srcu_struct *sp);
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup);
void show_rcu_gp_kthreads(void);
int rcu_get_gp_kthreads_prio(void);
void rcu_fwd_progress_check(unsigned long j);
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 29d2f4c..ec69273 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -245,12 +245,6 @@
return rcu_torture_writer_state_names[i];
}
-#if defined(CONFIG_RCU_BOOST) && defined(CONFIG_PREEMPT_RT)
-# define rcu_can_boost() 1
-#else
-# define rcu_can_boost() 0
-#endif
-
#ifdef CONFIG_RCU_TRACE
static u64 notrace rcu_trace_clock_local(void)
{
@@ -331,6 +325,7 @@
void (*read_delay)(struct torture_random_state *rrsp,
struct rt_read_seg *rtrsp);
void (*readunlock)(int idx);
+ int (*readlock_held)(void);
unsigned long (*get_gp_seq)(void);
unsigned long (*gp_diff)(unsigned long new, unsigned long old);
void (*deferred_free)(struct rcu_torture *p);
@@ -345,6 +340,7 @@
void (*fqs)(void);
void (*stats)(void);
void (*gp_kthread_dbg)(void);
+ bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
int (*stall_dur)(void);
int irq_capable;
int can_boost;
@@ -359,6 +355,11 @@
* Definitions for rcu torture testing.
*/
+static int torture_readlock_not_held(void)
+{
+ return rcu_read_lock_bh_held() || rcu_read_lock_sched_held();
+}
+
static int rcu_torture_read_lock(void) __acquires(RCU)
{
rcu_read_lock();
@@ -483,30 +484,32 @@
}
static struct rcu_torture_ops rcu_ops = {
- .ttype = RCU_FLAVOR,
- .init = rcu_sync_torture_init,
- .readlock = rcu_torture_read_lock,
- .read_delay = rcu_read_delay,
- .readunlock = rcu_torture_read_unlock,
- .get_gp_seq = rcu_get_gp_seq,
- .gp_diff = rcu_seq_diff,
- .deferred_free = rcu_torture_deferred_free,
- .sync = synchronize_rcu,
- .exp_sync = synchronize_rcu_expedited,
- .get_gp_state = get_state_synchronize_rcu,
- .start_gp_poll = start_poll_synchronize_rcu,
- .poll_gp_state = poll_state_synchronize_rcu,
- .cond_sync = cond_synchronize_rcu,
- .call = call_rcu,
- .cb_barrier = rcu_barrier,
- .fqs = rcu_force_quiescent_state,
- .stats = NULL,
- .gp_kthread_dbg = show_rcu_gp_kthreads,
- .stall_dur = rcu_jiffies_till_stall_check,
- .irq_capable = 1,
- .can_boost = rcu_can_boost(),
- .extendables = RCUTORTURE_MAX_EXTEND,
- .name = "rcu"
+ .ttype = RCU_FLAVOR,
+ .init = rcu_sync_torture_init,
+ .readlock = rcu_torture_read_lock,
+ .read_delay = rcu_read_delay,
+ .readunlock = rcu_torture_read_unlock,
+ .readlock_held = torture_readlock_not_held,
+ .get_gp_seq = rcu_get_gp_seq,
+ .gp_diff = rcu_seq_diff,
+ .deferred_free = rcu_torture_deferred_free,
+ .sync = synchronize_rcu,
+ .exp_sync = synchronize_rcu_expedited,
+ .get_gp_state = get_state_synchronize_rcu,
+ .start_gp_poll = start_poll_synchronize_rcu,
+ .poll_gp_state = poll_state_synchronize_rcu,
+ .cond_sync = cond_synchronize_rcu,
+ .call = call_rcu,
+ .cb_barrier = rcu_barrier,
+ .fqs = rcu_force_quiescent_state,
+ .stats = NULL,
+ .gp_kthread_dbg = show_rcu_gp_kthreads,
+ .check_boost_failed = rcu_check_boost_fail,
+ .stall_dur = rcu_jiffies_till_stall_check,
+ .irq_capable = 1,
+ .can_boost = IS_ENABLED(CONFIG_RCU_BOOST),
+ .extendables = RCUTORTURE_MAX_EXTEND,
+ .name = "rcu"
};
/*
@@ -540,6 +543,7 @@
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_torture_read_unlock,
+ .readlock_held = torture_readlock_not_held,
.get_gp_seq = rcu_no_completed,
.deferred_free = rcu_busted_torture_deferred_free,
.sync = synchronize_rcu_busted,
@@ -589,6 +593,11 @@
srcu_read_unlock(srcu_ctlp, idx);
}
+static int torture_srcu_read_lock_held(void)
+{
+ return srcu_read_lock_held(srcu_ctlp);
+}
+
static unsigned long srcu_torture_completed(void)
{
return srcu_batches_completed(srcu_ctlp);
@@ -646,6 +655,7 @@
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
+ .readlock_held = torture_srcu_read_lock_held,
.get_gp_seq = srcu_torture_completed,
.deferred_free = srcu_torture_deferred_free,
.sync = srcu_torture_synchronize,
@@ -681,6 +691,7 @@
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
+ .readlock_held = torture_srcu_read_lock_held,
.get_gp_seq = srcu_torture_completed,
.deferred_free = srcu_torture_deferred_free,
.sync = srcu_torture_synchronize,
@@ -700,6 +711,7 @@
.readlock = srcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = srcu_torture_read_unlock,
+ .readlock_held = torture_srcu_read_lock_held,
.get_gp_seq = srcu_torture_completed,
.deferred_free = srcu_torture_deferred_free,
.sync = srcu_torture_synchronize,
@@ -787,6 +799,7 @@
.readlock = rcu_torture_read_lock_trivial,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_torture_read_unlock_trivial,
+ .readlock_held = torture_readlock_not_held,
.get_gp_seq = rcu_no_completed,
.sync = synchronize_rcu_trivial,
.exp_sync = synchronize_rcu_trivial,
@@ -850,6 +863,7 @@
.readlock = tasks_tracing_torture_read_lock,
.read_delay = srcu_read_delay, /* just reuse srcu's version. */
.readunlock = tasks_tracing_torture_read_unlock,
+ .readlock_held = rcu_read_lock_trace_held,
.get_gp_seq = rcu_no_completed,
.deferred_free = rcu_tasks_tracing_torture_deferred_free,
.sync = synchronize_rcu_tasks_trace,
@@ -871,32 +885,13 @@
return cur_ops->gp_diff(new, old);
}
-static bool __maybe_unused torturing_tasks(void)
-{
- return cur_ops == &tasks_ops || cur_ops == &tasks_rude_ops;
-}
-
/*
* RCU torture priority-boost testing. Runs one real-time thread per
- * CPU for moderate bursts, repeatedly registering RCU callbacks and
- * spinning waiting for them to be invoked. If a given callback takes
- * too long to be invoked, we assume that priority inversion has occurred.
+ * CPU for moderate bursts, repeatedly starting grace periods and waiting
+ * for them to complete. If a given grace period takes too long, we assume
+ * that priority inversion has occurred.
*/
-struct rcu_boost_inflight {
- struct rcu_head rcu;
- int inflight;
-};
-
-static void rcu_torture_boost_cb(struct rcu_head *head)
-{
- struct rcu_boost_inflight *rbip =
- container_of(head, struct rcu_boost_inflight, rcu);
-
- /* Ensure RCU-core accesses precede clearing ->inflight */
- smp_store_release(&rbip->inflight, 0);
-}
-
static int old_rt_runtime = -1;
static void rcu_torture_disable_rt_throttle(void)
@@ -923,49 +918,68 @@
old_rt_runtime = -1;
}
-static bool rcu_torture_boost_failed(unsigned long start, unsigned long end)
+static bool rcu_torture_boost_failed(unsigned long gp_state, unsigned long *start)
{
+ int cpu;
static int dbg_done;
+ unsigned long end = jiffies;
+ bool gp_done;
+ unsigned long j;
+ static unsigned long last_persist;
+ unsigned long lp;
+ unsigned long mininterval = test_boost_duration * HZ - HZ / 2;
- if (end - start > test_boost_duration * HZ - HZ / 2) {
+ if (end - *start > mininterval) {
+ // Recheck after checking time to avoid false positives.
+ smp_mb(); // Time check before grace-period check.
+ if (cur_ops->poll_gp_state(gp_state))
+ return false; // passed, though perhaps just barely
+ if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, &cpu)) {
+ // At most one persisted message per boost test.
+ j = jiffies;
+ lp = READ_ONCE(last_persist);
+ if (time_after(j, lp + mininterval) && cmpxchg(&last_persist, lp, j) == lp)
+ pr_info("Boost inversion persisted: No QS from CPU %d\n", cpu);
+ return false; // passed on a technicality
+ }
VERBOSE_TOROUT_STRING("rcu_torture_boost boosting failed");
n_rcu_torture_boost_failure++;
- if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg)
+ if (!xchg(&dbg_done, 1) && cur_ops->gp_kthread_dbg) {
+ pr_info("Boost inversion thread ->rt_priority %u gp_state %lu jiffies %lu\n",
+ current->rt_priority, gp_state, end - *start);
cur_ops->gp_kthread_dbg();
+ // Recheck after print to flag grace period ending during splat.
+ gp_done = cur_ops->poll_gp_state(gp_state);
+ pr_info("Boost inversion: GP %lu %s.\n", gp_state,
+ gp_done ? "ended already" : "still pending");
- return true; /* failed */
+ }
+
+ return true; // failed
+ } else if (cur_ops->check_boost_failed && !cur_ops->check_boost_failed(gp_state, NULL)) {
+ *start = jiffies;
}
- return false; /* passed */
+ return false; // passed
}
static int rcu_torture_boost(void *arg)
{
- unsigned long call_rcu_time;
unsigned long endtime;
+ unsigned long gp_state;
+ unsigned long gp_state_time;
unsigned long oldstarttime;
- struct rcu_boost_inflight rbi = { .inflight = 0 };
VERBOSE_TOROUT_STRING("rcu_torture_boost started");
/* Set real-time priority. */
sched_set_fifo_low(current);
- init_rcu_head_on_stack(&rbi.rcu);
/* Each pass through the following loop does one boost-test cycle. */
do {
bool failed = false; // Test failed already in this test interval
- bool firsttime = true;
+ bool gp_initiated = false;
- /* Increment n_rcu_torture_boosts once per boost-test */
- while (!kthread_should_stop()) {
- if (mutex_trylock(&boost_mutex)) {
- n_rcu_torture_boosts++;
- mutex_unlock(&boost_mutex);
- break;
- }
- schedule_timeout_uninterruptible(1);
- }
if (kthread_should_stop())
goto checkwait;
@@ -979,33 +993,33 @@
goto checkwait;
}
- /* Do one boost-test interval. */
+ // Do one boost-test interval.
endtime = oldstarttime + test_boost_duration * HZ;
while (time_before(jiffies, endtime)) {
- /* If we don't have a callback in flight, post one. */
- if (!smp_load_acquire(&rbi.inflight)) {
- /* RCU core before ->inflight = 1. */
- smp_store_release(&rbi.inflight, 1);
- cur_ops->call(&rbi.rcu, rcu_torture_boost_cb);
- /* Check if the boost test failed */
- if (!firsttime && !failed)
- failed = rcu_torture_boost_failed(call_rcu_time, jiffies);
- call_rcu_time = jiffies;
- firsttime = false;
+ // Has current GP gone too long?
+ if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
+ failed = rcu_torture_boost_failed(gp_state, &gp_state_time);
+ // If we don't have a grace period in flight, start one.
+ if (!gp_initiated || cur_ops->poll_gp_state(gp_state)) {
+ gp_state = cur_ops->start_gp_poll();
+ gp_initiated = true;
+ gp_state_time = jiffies;
}
- if (stutter_wait("rcu_torture_boost"))
+ if (stutter_wait("rcu_torture_boost")) {
sched_set_fifo_low(current);
+ // If the grace period already ended,
+ // we don't know when that happened, so
+ // start over.
+ if (cur_ops->poll_gp_state(gp_state))
+ gp_initiated = false;
+ }
if (torture_must_stop())
goto checkwait;
}
- /*
- * If boost never happened, then inflight will always be 1, in
- * this case the boost check would never happen in the above
- * loop so do another one here.
- */
- if (!firsttime && !failed && smp_load_acquire(&rbi.inflight))
- rcu_torture_boost_failed(call_rcu_time, jiffies);
+ // In case the grace period extended beyond the end of the loop.
+ if (gp_initiated && !failed && !cur_ops->poll_gp_state(gp_state))
+ rcu_torture_boost_failed(gp_state, &gp_state_time);
/*
* Set the start time of the next test interval.
@@ -1014,11 +1028,12 @@
* interval. Besides, we are running at RT priority,
* so delays should be relatively rare.
*/
- while (oldstarttime == boost_starttime &&
- !kthread_should_stop()) {
+ while (oldstarttime == boost_starttime && !kthread_should_stop()) {
if (mutex_trylock(&boost_mutex)) {
- boost_starttime = jiffies +
- test_boost_interval * HZ;
+ if (oldstarttime == boost_starttime) {
+ boost_starttime = jiffies + test_boost_interval * HZ;
+ n_rcu_torture_boosts++;
+ }
mutex_unlock(&boost_mutex);
break;
}
@@ -1030,15 +1045,11 @@
sched_set_fifo_low(current);
} while (!torture_must_stop());
- while (smp_load_acquire(&rbi.inflight))
- schedule_timeout_uninterruptible(1); // rcu_barrier() deadlocks.
-
/* Clean up and exit. */
- while (!kthread_should_stop() || smp_load_acquire(&rbi.inflight)) {
+ while (!kthread_should_stop()) {
torture_shutdown_absorb("rcu_torture_boost");
schedule_timeout_uninterruptible(1);
}
- destroy_rcu_head_on_stack(&rbi.rcu);
torture_kthread_stopping("rcu_torture_boost");
return 0;
}
@@ -1553,11 +1564,7 @@
started = cur_ops->get_gp_seq();
ts = rcu_trace_clock_local();
p = rcu_dereference_check(rcu_torture_current,
- rcu_read_lock_bh_held() ||
- rcu_read_lock_sched_held() ||
- srcu_read_lock_held(srcu_ctlp) ||
- rcu_read_lock_trace_held() ||
- torturing_tasks());
+ !cur_ops->readlock_held || cur_ops->readlock_held());
if (p == NULL) {
/* Wait for rcu_torture_writer to get underway */
rcutorture_one_extend(&readstate, 0, trsp, rtrsp);
@@ -1861,48 +1868,49 @@
torture_shutdown_absorb("rcu_torture_stats");
} while (!torture_must_stop());
torture_kthread_stopping("rcu_torture_stats");
-
- {
- struct rcu_head *rhp;
- struct kmem_cache *kcp;
- static int z;
-
- kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
- rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
- pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
- pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
- mem_dump_obj(ZERO_SIZE_PTR);
- pr_alert("mem_dump_obj(NULL):");
- mem_dump_obj(NULL);
- pr_alert("mem_dump_obj(%px):", &rhp);
- mem_dump_obj(&rhp);
- pr_alert("mem_dump_obj(%px):", rhp);
- mem_dump_obj(rhp);
- pr_alert("mem_dump_obj(%px):", &rhp->func);
- mem_dump_obj(&rhp->func);
- pr_alert("mem_dump_obj(%px):", &z);
- mem_dump_obj(&z);
- kmem_cache_free(kcp, rhp);
- kmem_cache_destroy(kcp);
- rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
- pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
- pr_alert("mem_dump_obj(kmalloc %px):", rhp);
- mem_dump_obj(rhp);
- pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
- mem_dump_obj(&rhp->func);
- kfree(rhp);
- rhp = vmalloc(4096);
- pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
- pr_alert("mem_dump_obj(vmalloc %px):", rhp);
- mem_dump_obj(rhp);
- pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
- mem_dump_obj(&rhp->func);
- vfree(rhp);
- }
-
return 0;
}
+/* Test mem_dump_obj() and friends. */
+static void rcu_torture_mem_dump_obj(void)
+{
+ struct rcu_head *rhp;
+ struct kmem_cache *kcp;
+ static int z;
+
+ kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
+ rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
+ pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
+ pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
+ mem_dump_obj(ZERO_SIZE_PTR);
+ pr_alert("mem_dump_obj(NULL):");
+ mem_dump_obj(NULL);
+ pr_alert("mem_dump_obj(%px):", &rhp);
+ mem_dump_obj(&rhp);
+ pr_alert("mem_dump_obj(%px):", rhp);
+ mem_dump_obj(rhp);
+ pr_alert("mem_dump_obj(%px):", &rhp->func);
+ mem_dump_obj(&rhp->func);
+ pr_alert("mem_dump_obj(%px):", &z);
+ mem_dump_obj(&z);
+ kmem_cache_free(kcp, rhp);
+ kmem_cache_destroy(kcp);
+ rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+ pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+ pr_alert("mem_dump_obj(kmalloc %px):", rhp);
+ mem_dump_obj(rhp);
+ pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
+ mem_dump_obj(&rhp->func);
+ kfree(rhp);
+ rhp = vmalloc(4096);
+ pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+ pr_alert("mem_dump_obj(vmalloc %px):", rhp);
+ mem_dump_obj(rhp);
+ pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
+ mem_dump_obj(&rhp->func);
+ vfree(rhp);
+}
+
static void
rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
{
@@ -2634,7 +2642,7 @@
if (!(test_boost == 1 && cur_ops->can_boost) && test_boost != 2)
return false;
- if (!cur_ops->call)
+ if (!cur_ops->start_gp_poll || !cur_ops->poll_gp_state)
return false;
prio = rcu_get_gp_kthreads_prio();
@@ -2642,7 +2650,7 @@
return false;
if (prio < 2) {
- if (boost_warn_once == 1)
+ if (boost_warn_once == 1)
return false;
pr_alert("%s: WARN: RCU kthread priority too low to test boosting. Skipping RCU boost test. Try passing rcutree.kthread_prio > 1 on the kernel command line.\n", KBUILD_MODNAME);
@@ -2818,6 +2826,8 @@
if (cur_ops->cleanup != NULL)
cur_ops->cleanup();
+ rcu_torture_mem_dump_obj();
+
rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
if (err_segs_recorded) {
@@ -3120,6 +3130,21 @@
if (firsterr < 0)
goto unwind;
rcutor_hp = firsterr;
+
+ // Testing RCU priority boosting requires rcutorture do
+ // some serious abuse. Counter this by running ksoftirqd
+ // at higher priority.
+ if (IS_BUILTIN(CONFIG_RCU_TORTURE_TEST)) {
+ for_each_online_cpu(cpu) {
+ struct sched_param sp;
+ struct task_struct *t;
+
+ t = per_cpu(ksoftirqd, cpu);
+ WARN_ON_ONCE(!t);
+ sp.sched_priority = 2;
+ sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
+ }
+ }
}
shutdown_jiffies = jiffies + shutdown_secs * HZ;
firsterr = torture_shutdown_init(shutdown_secs, rcu_torture_cleanup);
diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c
index 02dd976..313d454 100644
--- a/kernel/rcu/refscale.c
+++ b/kernel/rcu/refscale.c
@@ -362,6 +362,111 @@
.name = "rwsem"
};
+// Definitions for global spinlock
+static DEFINE_SPINLOCK(test_lock);
+
+static void ref_lock_section(const int nloops)
+{
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ spin_lock(&test_lock);
+ spin_unlock(&test_lock);
+ }
+ preempt_enable();
+}
+
+static void ref_lock_delay_section(const int nloops, const int udl, const int ndl)
+{
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ spin_lock(&test_lock);
+ un_delay(udl, ndl);
+ spin_unlock(&test_lock);
+ }
+ preempt_enable();
+}
+
+static struct ref_scale_ops lock_ops = {
+ .readsection = ref_lock_section,
+ .delaysection = ref_lock_delay_section,
+ .name = "lock"
+};
+
+// Definitions for global irq-save spinlock
+
+static void ref_lock_irq_section(const int nloops)
+{
+ unsigned long flags;
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ spin_lock_irqsave(&test_lock, flags);
+ spin_unlock_irqrestore(&test_lock, flags);
+ }
+ preempt_enable();
+}
+
+static void ref_lock_irq_delay_section(const int nloops, const int udl, const int ndl)
+{
+ unsigned long flags;
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ spin_lock_irqsave(&test_lock, flags);
+ un_delay(udl, ndl);
+ spin_unlock_irqrestore(&test_lock, flags);
+ }
+ preempt_enable();
+}
+
+static struct ref_scale_ops lock_irq_ops = {
+ .readsection = ref_lock_irq_section,
+ .delaysection = ref_lock_irq_delay_section,
+ .name = "lock-irq"
+};
+
+// Definitions acquire-release.
+static DEFINE_PER_CPU(unsigned long, test_acqrel);
+
+static void ref_acqrel_section(const int nloops)
+{
+ unsigned long x;
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+ smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+ }
+ preempt_enable();
+}
+
+static void ref_acqrel_delay_section(const int nloops, const int udl, const int ndl)
+{
+ unsigned long x;
+ int i;
+
+ preempt_disable();
+ for (i = nloops; i >= 0; i--) {
+ x = smp_load_acquire(this_cpu_ptr(&test_acqrel));
+ un_delay(udl, ndl);
+ smp_store_release(this_cpu_ptr(&test_acqrel), x + 1);
+ }
+ preempt_enable();
+}
+
+static struct ref_scale_ops acqrel_ops = {
+ .readsection = ref_acqrel_section,
+ .delaysection = ref_acqrel_delay_section,
+ .name = "acqrel"
+};
+
static void rcu_scale_one_reader(void)
{
if (readdelay <= 0)
@@ -653,8 +758,8 @@
long i;
int firsterr = 0;
static struct ref_scale_ops *scale_ops[] = {
- &rcu_ops, &srcu_ops, &rcu_trace_ops, &rcu_tasks_ops,
- &refcnt_ops, &rwlock_ops, &rwsem_ops,
+ &rcu_ops, &srcu_ops, &rcu_trace_ops, &rcu_tasks_ops, &refcnt_ops, &rwlock_ops,
+ &rwsem_ops, &lock_ops, &lock_irq_ops, &acqrel_ops,
};
if (!torture_init_begin(scale_type, verbose))
diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index e26547b..6833d88 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -80,7 +80,7 @@
* srcu_read_unlock() running against them. So if the is_static parameter
* is set, don't initialize ->srcu_lock_count[] and ->srcu_unlock_count[].
*/
-static void init_srcu_struct_nodes(struct srcu_struct *ssp, bool is_static)
+static void init_srcu_struct_nodes(struct srcu_struct *ssp)
{
int cpu;
int i;
@@ -90,6 +90,9 @@
struct srcu_node *snp;
struct srcu_node *snp_first;
+ /* Initialize geometry if it has not already been initialized. */
+ rcu_init_geometry();
+
/* Work out the overall tree geometry. */
ssp->level[0] = &ssp->node[0];
for (i = 1; i < rcu_num_lvls; i++)
@@ -148,14 +151,6 @@
timer_setup(&sdp->delay_work, srcu_delay_timer, 0);
sdp->ssp = ssp;
sdp->grpmask = 1 << (cpu - sdp->mynode->grplo);
- if (is_static)
- continue;
-
- /* Dynamically allocated, better be no srcu_read_locks()! */
- for (i = 0; i < ARRAY_SIZE(sdp->srcu_lock_count); i++) {
- sdp->srcu_lock_count[i] = 0;
- sdp->srcu_unlock_count[i] = 0;
- }
}
}
@@ -179,7 +174,7 @@
ssp->sda = alloc_percpu(struct srcu_data);
if (!ssp->sda)
return -ENOMEM;
- init_srcu_struct_nodes(ssp, is_static);
+ init_srcu_struct_nodes(ssp);
ssp->srcu_gp_seq_needed_exp = 0;
ssp->srcu_last_gp_end = ktime_get_mono_fast_ns();
smp_store_release(&ssp->srcu_gp_seq_needed, 0); /* Init done. */
@@ -777,9 +772,9 @@
spin_unlock_irqrestore_rcu_node(sdp, flags);
/*
- * No local callbacks, so probabalistically probe global state.
+ * No local callbacks, so probabilistically probe global state.
* Exact information would require acquiring locks, which would
- * kill scalability, hence the probabalistic nature of the probe.
+ * kill scalability, hence the probabilistic nature of the probe.
*/
/* First, see if enough time has passed since the last GP. */
@@ -1000,6 +995,9 @@
* synchronize_srcu(), srcu_read_lock(), and srcu_read_unlock() are
* passed the same srcu_struct structure.
*
+ * Implementation of these memory-ordering guarantees is similar to
+ * that of synchronize_rcu().
+ *
* If SRCU is likely idle, expedite the first request. This semantic
* was provided by Classic SRCU, and is relied upon by its users, so TREE
* SRCU must also provide it. Note that detecting idleness is heuristic
@@ -1392,11 +1390,15 @@
{
struct srcu_struct *ssp;
+ /*
+ * Once that is set, call_srcu() can follow the normal path and
+ * queue delayed work. This must follow RCU workqueues creation
+ * and timers initialization.
+ */
srcu_init_done = true;
while (!list_empty(&srcu_boot_list)) {
ssp = list_first_entry(&srcu_boot_list, struct srcu_struct,
work.work.entry);
- check_init_srcu_struct(ssp);
list_del_init(&ssp->work.work.entry);
queue_work(rcu_gp_wq, &ssp->work.work);
}
diff --git a/kernel/rcu/sync.c b/kernel/rcu/sync.c
index d4558ab..33d896d 100644
--- a/kernel/rcu/sync.c
+++ b/kernel/rcu/sync.c
@@ -94,9 +94,9 @@
rcu_sync_call(rsp);
} else {
/*
- * We're at least a GP after the last rcu_sync_exit(); eveybody
+ * We're at least a GP after the last rcu_sync_exit(); everybody
* will now have observed the write side critical section.
- * Let 'em rip!.
+ * Let 'em rip!
*/
WRITE_ONCE(rsp->gp_state, GP_IDLE);
}
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 350ebf5..03a118d 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -23,7 +23,7 @@
* struct rcu_tasks - Definition for a Tasks-RCU-like mechanism.
* @cbs_head: Head of callback list.
* @cbs_tail: Tail pointer for callback list.
- * @cbs_wq: Wait queue allowning new callback to get kthread's attention.
+ * @cbs_wq: Wait queue allowing new callback to get kthread's attention.
* @cbs_lock: Lock protecting callback list.
* @kthread_ptr: This flavor's grace-period/callback-invocation kthread.
* @gp_func: This flavor's grace-period-wait function.
@@ -377,6 +377,46 @@
// Finally, this implementation does not support high call_rcu_tasks()
// rates from multiple CPUs. If this is required, per-CPU callback lists
// will be needed.
+//
+// The implementation uses rcu_tasks_wait_gp(), which relies on function
+// pointers in the rcu_tasks structure. The rcu_spawn_tasks_kthread()
+// function sets these function pointers up so that rcu_tasks_wait_gp()
+// invokes these functions in this order:
+//
+// rcu_tasks_pregp_step():
+// Invokes synchronize_rcu() in order to wait for all in-flight
+// t->on_rq and t->nvcsw transitions to complete. This works because
+// all such transitions are carried out with interrupts disabled.
+// rcu_tasks_pertask(), invoked on every non-idle task:
+// For every runnable non-idle task other than the current one, use
+// get_task_struct() to pin down that task, snapshot that task's
+// number of voluntary context switches, and add that task to the
+// holdout list.
+// rcu_tasks_postscan():
+// Invoke synchronize_srcu() to ensure that all tasks that were
+// in the process of exiting (and which thus might not know to
+// synchronize with this RCU Tasks grace period) have completed
+// exiting.
+// check_all_holdout_tasks(), repeatedly until holdout list is empty:
+// Scans the holdout list, attempting to identify a quiescent state
+// for each task on the list. If there is a quiescent state, the
+// corresponding task is removed from the holdout list.
+// rcu_tasks_postgp():
+// Invokes synchronize_rcu() in order to ensure that all prior
+// t->on_rq and t->nvcsw transitions are seen by all CPUs and tasks
+// to have happened before the end of this RCU Tasks grace period.
+// Again, this works because all such transitions are carried out
+// with interrupts disabled.
+//
+// For each exiting task, the exit_tasks_rcu_start() and
+// exit_tasks_rcu_finish() functions begin and end, respectively, the SRCU
+// read-side critical sections waited for by rcu_tasks_postscan().
+//
+// Pre-grace-period update-side code is ordered before the grace via the
+// ->cbs_lock and the smp_mb__after_spinlock(). Pre-grace-period read-side
+// code is ordered before the grace period via synchronize_rcu() call
+// in rcu_tasks_pregp_step() and by the scheduler's locks and interrupt
+// disabling.
/* Pre-grace-period preparation. */
static void rcu_tasks_pregp_step(void)
@@ -504,7 +544,7 @@
* or transition to usermode execution. As such, there are no read-side
* primitives analogous to rcu_read_lock() and rcu_read_unlock() because
* this primitive is intended to determine that all tasks have passed
- * through a safe state, not so much for data-strcuture synchronization.
+ * through a safe state, not so much for data-structure synchronization.
*
* See the description of call_rcu() for more detailed information on
* memory ordering guarantees.
@@ -605,8 +645,13 @@
// passing an empty function to schedule_on_each_cpu(). This approach
// provides an asynchronous call_rcu_tasks_rude() API and batching
// of concurrent calls to the synchronous synchronize_rcu_rude() API.
-// This sends IPIs far and wide and induces otherwise unnecessary context
-// switches on all online CPUs, whether idle or not.
+// This invokes schedule_on_each_cpu() in order to send IPIs far and wide
+// and induces otherwise unnecessary context switches on all online CPUs,
+// whether idle or not.
+//
+// Callback handling is provided by the rcu_tasks_kthread() function.
+//
+// Ordering is provided by the scheduler's context-switch code.
// Empty function to allow workqueues to force a context switch.
static void rcu_tasks_be_rude(struct work_struct *work)
@@ -637,7 +682,7 @@
* there are no read-side primitives analogous to rcu_read_lock() and
* rcu_read_unlock() because this primitive is intended to determine
* that all tasks have passed through a safe state, not so much for
- * data-strcuture synchronization.
+ * data-structure synchronization.
*
* See the description of call_rcu() for more detailed information on
* memory ordering guarantees.
@@ -1163,7 +1208,7 @@
* there are no read-side primitives analogous to rcu_read_lock() and
* rcu_read_unlock() because this primitive is intended to determine
* that all tasks have passed through a safe state, not so much for
- * data-strcuture synchronization.
+ * data-structure synchronization.
*
* See the description of call_rcu() for more detailed information on
* memory ordering guarantees.
@@ -1356,5 +1401,4 @@
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
static inline void rcu_tasks_bootup_oddness(void) {}
-void show_rcu_tasks_gp_kthreads(void) {}
#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
diff --git a/kernel/rcu/tiny.c b/kernel/rcu/tiny.c
index c8a029f..340b3f8 100644
--- a/kernel/rcu/tiny.c
+++ b/kernel/rcu/tiny.c
@@ -221,5 +221,4 @@
{
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
rcu_early_boot_tests();
- srcu_init();
}
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 8e78b24..28f1093 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -186,6 +186,17 @@
static int rcu_min_cached_objs = 5;
module_param(rcu_min_cached_objs, int, 0444);
+// A page shrinker can ask for pages to be freed to make them
+// available for other parts of the system. This usually happens
+// under low memory conditions, and in that case we should also
+// defer page-cache filling for a short time period.
+//
+// The default value is 5 seconds, which is long enough to reduce
+// interference with the shrinker while it asks other systems to
+// drain their caches.
+static int rcu_delay_page_cache_fill_msec = 5000;
+module_param(rcu_delay_page_cache_fill_msec, int, 0444);
+
/* Retrieve RCU kthreads priority for rcutorture */
int rcu_get_gp_kthreads_prio(void)
{
@@ -202,7 +213,7 @@
* the need for long delays to increase some race probabilities with the
* need for fast grace periods to increase other race probabilities.
*/
-#define PER_RCU_NODE_PERIOD 3 /* Number of grace periods between delays. */
+#define PER_RCU_NODE_PERIOD 3 /* Number of grace periods between delays for debugging. */
/*
* Compute the mask of online CPUs for the specified rcu_node structure.
@@ -242,6 +253,7 @@
{
rcu_qs();
rcu_preempt_deferred_qs(current);
+ rcu_tasks_qs(current, false);
}
/*
@@ -833,28 +845,6 @@
rcu_nmi_exit();
}
-/**
- * rcu_irq_exit_preempt - Inform RCU that current CPU is exiting irq
- * towards in kernel preemption
- *
- * Same as rcu_irq_exit() but has a sanity check that scheduling is safe
- * from RCU point of view. Invoked from return from interrupt before kernel
- * preemption.
- */
-void rcu_irq_exit_preempt(void)
-{
- lockdep_assert_irqs_disabled();
- rcu_nmi_exit();
-
- RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nesting) <= 0,
- "RCU dynticks_nesting counter underflow/zero!");
- RCU_LOCKDEP_WARN(__this_cpu_read(rcu_data.dynticks_nmi_nesting) !=
- DYNTICK_IRQ_NONIDLE,
- "Bad RCU dynticks_nmi_nesting counter\n");
- RCU_LOCKDEP_WARN(rcu_dynticks_curr_cpu_in_eqs(),
- "RCU in extended quiescent state!");
-}
-
#ifdef CONFIG_PROVE_RCU
/**
* rcu_irq_exit_check_preempt - Validate that scheduling is possible
@@ -959,7 +949,7 @@
*/
void noinstr rcu_user_exit(void)
{
- rcu_eqs_exit(1);
+ rcu_eqs_exit(true);
}
/**
@@ -1225,7 +1215,7 @@
#endif /* #if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU) */
/*
- * We are reporting a quiescent state on behalf of some other CPU, so
+ * When trying to report a quiescent state on behalf of some other CPU,
* it is our responsibility to check for and handle potential overflow
* of the rcu_node ->gp_seq counter with respect to the rcu_data counters.
* After all, the CPU might be in deep idle state, and thus executing no
@@ -2048,7 +2038,7 @@
/*
* Clean up after the old grace period.
*/
-static void rcu_gp_cleanup(void)
+static noinline void rcu_gp_cleanup(void)
{
int cpu;
bool needgp = false;
@@ -2489,7 +2479,7 @@
/*
* Invoke any RCU callbacks that have made it to the end of their grace
- * period. Thottle as specified by rdp->blimit.
+ * period. Throttle as specified by rdp->blimit.
*/
static void rcu_do_batch(struct rcu_data *rdp)
{
@@ -2629,7 +2619,7 @@
* state, for example, user mode or idle loop. It also schedules RCU
* core processing. If the current grace period has gone on too long,
* it will ask the scheduler to manufacture a context switch for the sole
- * purpose of providing a providing the needed quiescent state.
+ * purpose of providing the needed quiescent state.
*/
void rcu_sched_clock_irq(int user)
{
@@ -2911,7 +2901,6 @@
"%s: Could not start rcuc kthread, OOM is now expected behavior\n", __func__);
return 0;
}
-early_initcall(rcu_spawn_core_kthreads);
/*
* Handle any core-RCU processing required by a call_rcu() invocation.
@@ -3082,12 +3071,14 @@
* period elapses, in other words after all pre-existing RCU read-side
* critical sections have completed. However, the callback function
* might well execute concurrently with RCU read-side critical sections
- * that started after call_rcu() was invoked. RCU read-side critical
- * sections are delimited by rcu_read_lock() and rcu_read_unlock(), and
- * may be nested. In addition, regions of code across which interrupts,
- * preemption, or softirqs have been disabled also serve as RCU read-side
- * critical sections. This includes hardware interrupt handlers, softirq
- * handlers, and NMI handlers.
+ * that started after call_rcu() was invoked.
+ *
+ * RCU read-side critical sections are delimited by rcu_read_lock()
+ * and rcu_read_unlock(), and may be nested. In addition, but only in
+ * v5.0 and later, regions of code across which interrupts, preemption,
+ * or softirqs have been disabled also serve as RCU read-side critical
+ * sections. This includes hardware interrupt handlers, softirq handlers,
+ * and NMI handlers.
*
* Note that all CPUs must agree that the grace period extended beyond
* all pre-existing RCU read-side critical section. On systems with more
@@ -3107,6 +3098,9 @@
* between the call to call_rcu() and the invocation of "func()" -- even
* if CPU A and CPU B are the same CPU (but again only if the system has
* more than one CPU).
+ *
+ * Implementation of these memory-ordering guarantees is described here:
+ * Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst.
*/
void call_rcu(struct rcu_head *head, rcu_callback_t func)
{
@@ -3171,6 +3165,7 @@
* Even though it is lockless an access has to be protected by the
* per-cpu lock.
* @page_cache_work: A work to refill the cache when it is empty
+ * @backoff_page_cache_fill: Delay cache refills
* @work_in_progress: Indicates that page_cache_work is running
* @hrtimer: A hrtimer for scheduling a page_cache_work
* @nr_bkv_objs: number of allocated objects at @bkvcache.
@@ -3190,7 +3185,8 @@
bool initialized;
int count;
- struct work_struct page_cache_work;
+ struct delayed_work page_cache_work;
+ atomic_t backoff_page_cache_fill;
atomic_t work_in_progress;
struct hrtimer hrtimer;
@@ -3237,7 +3233,7 @@
if (!krcp->nr_bkv_objs)
return NULL;
- krcp->nr_bkv_objs--;
+ WRITE_ONCE(krcp->nr_bkv_objs, krcp->nr_bkv_objs - 1);
return (struct kvfree_rcu_bulk_data *)
llist_del_first(&krcp->bkvcache);
}
@@ -3251,14 +3247,33 @@
return false;
llist_add((struct llist_node *) bnode, &krcp->bkvcache);
- krcp->nr_bkv_objs++;
+ WRITE_ONCE(krcp->nr_bkv_objs, krcp->nr_bkv_objs + 1);
return true;
+}
+static int
+drain_page_cache(struct kfree_rcu_cpu *krcp)
+{
+ unsigned long flags;
+ struct llist_node *page_list, *pos, *n;
+ int freed = 0;
+
+ raw_spin_lock_irqsave(&krcp->lock, flags);
+ page_list = llist_del_all(&krcp->bkvcache);
+ WRITE_ONCE(krcp->nr_bkv_objs, 0);
+ raw_spin_unlock_irqrestore(&krcp->lock, flags);
+
+ llist_for_each_safe(pos, n, page_list) {
+ free_page((unsigned long)pos);
+ freed++;
+ }
+
+ return freed;
}
/*
* This function is invoked in workqueue context after a grace period.
- * It frees all the objects queued on ->bhead_free or ->head_free.
+ * It frees all the objects queued on ->bkvhead_free or ->head_free.
*/
static void kfree_rcu_work(struct work_struct *work)
{
@@ -3285,7 +3300,7 @@
krwp->head_free = NULL;
raw_spin_unlock_irqrestore(&krcp->lock, flags);
- // Handle two first channels.
+ // Handle the first two channels.
for (i = 0; i < FREE_N_CHANNELS; i++) {
for (; bkvhead[i]; bkvhead[i] = bnext) {
bnext = bkvhead[i]->next;
@@ -3323,9 +3338,11 @@
}
/*
- * Emergency case only. It can happen under low memory
- * condition when an allocation gets failed, so the "bulk"
- * path can not be temporary maintained.
+ * This is used when the "bulk" path can not be used for the
+ * double-argument of kvfree_rcu(). This happens when the
+ * page-cache is empty, which means that objects are instead
+ * queued on a linked list through their rcu_head structures.
+ * This list is named "Channel 3".
*/
for (; head; head = next) {
unsigned long offset = (unsigned long)head->func;
@@ -3345,34 +3362,31 @@
}
/*
- * Schedule the kfree batch RCU work to run in workqueue context after a GP.
- *
- * This function is invoked by kfree_rcu_monitor() when the KFREE_DRAIN_JIFFIES
- * timeout has been reached.
+ * This function is invoked after the KFREE_DRAIN_JIFFIES timeout.
*/
-static inline bool queue_kfree_rcu_work(struct kfree_rcu_cpu *krcp)
+static void kfree_rcu_monitor(struct work_struct *work)
{
- struct kfree_rcu_cpu_work *krwp;
- bool repeat = false;
+ struct kfree_rcu_cpu *krcp = container_of(work,
+ struct kfree_rcu_cpu, monitor_work.work);
+ unsigned long flags;
int i, j;
- lockdep_assert_held(&krcp->lock);
+ raw_spin_lock_irqsave(&krcp->lock, flags);
+ // Attempt to start a new batch.
for (i = 0; i < KFREE_N_BATCHES; i++) {
- krwp = &(krcp->krw_arr[i]);
+ struct kfree_rcu_cpu_work *krwp = &(krcp->krw_arr[i]);
- /*
- * Try to detach bkvhead or head and attach it over any
- * available corresponding free channel. It can be that
- * a previous RCU batch is in progress, it means that
- * immediately to queue another one is not possible so
- * return false to tell caller to retry.
- */
+ // Try to detach bkvhead or head and attach it over any
+ // available corresponding free channel. It can be that
+ // a previous RCU batch is in progress, it means that
+ // immediately to queue another one is not possible so
+ // in that case the monitor work is rearmed.
if ((krcp->bkvhead[0] && !krwp->bkvhead_free[0]) ||
(krcp->bkvhead[1] && !krwp->bkvhead_free[1]) ||
(krcp->head && !krwp->head_free)) {
- // Channel 1 corresponds to SLAB ptrs.
- // Channel 2 corresponds to vmalloc ptrs.
+ // Channel 1 corresponds to the SLAB-pointer bulk path.
+ // Channel 2 corresponds to vmalloc-pointer bulk path.
for (j = 0; j < FREE_N_CHANNELS; j++) {
if (!krwp->bkvhead_free[j]) {
krwp->bkvhead_free[j] = krcp->bkvhead[j];
@@ -3380,7 +3394,8 @@
}
}
- // Channel 3 corresponds to emergency path.
+ // Channel 3 corresponds to both SLAB and vmalloc
+ // objects queued on the linked list.
if (!krwp->head_free) {
krwp->head_free = krcp->head;
krcp->head = NULL;
@@ -3388,56 +3403,26 @@
WRITE_ONCE(krcp->count, 0);
- /*
- * One work is per one batch, so there are three
- * "free channels", the batch can handle. It can
- * be that the work is in the pending state when
- * channels have been detached following by each
- * other.
- */
+ // One work is per one batch, so there are three
+ // "free channels", the batch can handle. It can
+ // be that the work is in the pending state when
+ // channels have been detached following by each
+ // other.
queue_rcu_work(system_wq, &krwp->rcu_work);
}
-
- // Repeat if any "free" corresponding channel is still busy.
- if (krcp->bkvhead[0] || krcp->bkvhead[1] || krcp->head)
- repeat = true;
}
- return !repeat;
-}
-
-static inline void kfree_rcu_drain_unlock(struct kfree_rcu_cpu *krcp,
- unsigned long flags)
-{
- // Attempt to start a new batch.
- krcp->monitor_todo = false;
- if (queue_kfree_rcu_work(krcp)) {
- // Success! Our job is done here.
- raw_spin_unlock_irqrestore(&krcp->lock, flags);
- return;
- }
-
- // Previous RCU batch still in progress, try again later.
- krcp->monitor_todo = true;
- schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
- raw_spin_unlock_irqrestore(&krcp->lock, flags);
-}
-
-/*
- * This function is invoked after the KFREE_DRAIN_JIFFIES timeout.
- * It invokes kfree_rcu_drain_unlock() to attempt to start another batch.
- */
-static void kfree_rcu_monitor(struct work_struct *work)
-{
- unsigned long flags;
- struct kfree_rcu_cpu *krcp = container_of(work, struct kfree_rcu_cpu,
- monitor_work.work);
-
- raw_spin_lock_irqsave(&krcp->lock, flags);
- if (krcp->monitor_todo)
- kfree_rcu_drain_unlock(krcp, flags);
+ // If there is nothing to detach, it means that our job is
+ // successfully done here. In case of having at least one
+ // of the channels that is still busy we should rearm the
+ // work to repeat an attempt. Because previous batches are
+ // still in progress.
+ if (!krcp->bkvhead[0] && !krcp->bkvhead[1] && !krcp->head)
+ krcp->monitor_todo = false;
else
- raw_spin_unlock_irqrestore(&krcp->lock, flags);
+ schedule_delayed_work(&krcp->monitor_work, KFREE_DRAIN_JIFFIES);
+
+ raw_spin_unlock_irqrestore(&krcp->lock, flags);
}
static enum hrtimer_restart
@@ -3446,7 +3431,7 @@
struct kfree_rcu_cpu *krcp =
container_of(t, struct kfree_rcu_cpu, hrtimer);
- queue_work(system_highpri_wq, &krcp->page_cache_work);
+ queue_delayed_work(system_highpri_wq, &krcp->page_cache_work, 0);
return HRTIMER_NORESTART;
}
@@ -3455,12 +3440,16 @@
struct kvfree_rcu_bulk_data *bnode;
struct kfree_rcu_cpu *krcp =
container_of(work, struct kfree_rcu_cpu,
- page_cache_work);
+ page_cache_work.work);
unsigned long flags;
+ int nr_pages;
bool pushed;
int i;
- for (i = 0; i < rcu_min_cached_objs; i++) {
+ nr_pages = atomic_read(&krcp->backoff_page_cache_fill) ?
+ 1 : rcu_min_cached_objs;
+
+ for (i = 0; i < nr_pages; i++) {
bnode = (struct kvfree_rcu_bulk_data *)
__get_free_page(GFP_KERNEL | __GFP_NORETRY | __GFP_NOMEMALLOC | __GFP_NOWARN);
@@ -3477,6 +3466,7 @@
}
atomic_set(&krcp->work_in_progress, 0);
+ atomic_set(&krcp->backoff_page_cache_fill, 0);
}
static void
@@ -3484,10 +3474,15 @@
{
if (rcu_scheduler_active == RCU_SCHEDULER_RUNNING &&
!atomic_xchg(&krcp->work_in_progress, 1)) {
- hrtimer_init(&krcp->hrtimer, CLOCK_MONOTONIC,
- HRTIMER_MODE_REL);
- krcp->hrtimer.function = schedule_page_work_fn;
- hrtimer_start(&krcp->hrtimer, 0, HRTIMER_MODE_REL);
+ if (atomic_read(&krcp->backoff_page_cache_fill)) {
+ queue_delayed_work(system_wq,
+ &krcp->page_cache_work,
+ msecs_to_jiffies(rcu_delay_page_cache_fill_msec));
+ } else {
+ hrtimer_init(&krcp->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+ krcp->hrtimer.function = schedule_page_work_fn;
+ hrtimer_start(&krcp->hrtimer, 0, HRTIMER_MODE_REL);
+ }
}
}
@@ -3552,11 +3547,11 @@
}
/*
- * Queue a request for lazy invocation of appropriate free routine after a
- * grace period. Please note there are three paths are maintained, two are the
- * main ones that use array of pointers interface and third one is emergency
- * one, that is used only when the main path can not be maintained temporary,
- * due to memory pressure.
+ * Queue a request for lazy invocation of the appropriate free routine
+ * after a grace period. Please note that three paths are maintained,
+ * two for the common case using arrays of pointers and a third one that
+ * is used only when the main paths cannot be used, for example, due to
+ * memory pressure.
*
* Each kvfree_call_rcu() request is added to a batch. The batch will be drained
* every KFREE_DRAIN_JIFFIES number of jiffies. All the objects in the batch will
@@ -3645,6 +3640,8 @@
struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
count += READ_ONCE(krcp->count);
+ count += READ_ONCE(krcp->nr_bkv_objs);
+ atomic_set(&krcp->backoff_page_cache_fill, 1);
}
return count;
@@ -3654,18 +3651,14 @@
kfree_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
{
int cpu, freed = 0;
- unsigned long flags;
for_each_possible_cpu(cpu) {
int count;
struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
count = krcp->count;
- raw_spin_lock_irqsave(&krcp->lock, flags);
- if (krcp->monitor_todo)
- kfree_rcu_drain_unlock(krcp, flags);
- else
- raw_spin_unlock_irqrestore(&krcp->lock, flags);
+ count += drain_page_cache(krcp);
+ kfree_rcu_monitor(&krcp->monitor_work.work);
sc->nr_to_scan -= count;
freed += count;
@@ -3693,7 +3686,8 @@
struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
raw_spin_lock_irqsave(&krcp->lock, flags);
- if (!krcp->head || krcp->monitor_todo) {
+ if ((!krcp->bkvhead[0] && !krcp->bkvhead[1] && !krcp->head) ||
+ krcp->monitor_todo) {
raw_spin_unlock_irqrestore(&krcp->lock, flags);
continue;
}
@@ -3750,10 +3744,12 @@
* read-side critical sections have completed. Note, however, that
* upon return from synchronize_rcu(), the caller might well be executing
* concurrently with new RCU read-side critical sections that began while
- * synchronize_rcu() was waiting. RCU read-side critical sections are
- * delimited by rcu_read_lock() and rcu_read_unlock(), and may be nested.
- * In addition, regions of code across which interrupts, preemption, or
- * softirqs have been disabled also serve as RCU read-side critical
+ * synchronize_rcu() was waiting.
+ *
+ * RCU read-side critical sections are delimited by rcu_read_lock()
+ * and rcu_read_unlock(), and may be nested. In addition, but only in
+ * v5.0 and later, regions of code across which interrupts, preemption,
+ * or softirqs have been disabled also serve as RCU read-side critical
* sections. This includes hardware interrupt handlers, softirq handlers,
* and NMI handlers.
*
@@ -3774,6 +3770,9 @@
* to have executed a full memory barrier during the execution of
* synchronize_rcu() -- even if CPU A and CPU B are the same CPU (but
* again only if the system has more than one CPU).
+ *
+ * Implementation of these memory-ordering guarantees is described here:
+ * Documentation/RCU/Design/Memory-Ordering/Tree-RCU-Memory-Ordering.rst.
*/
void synchronize_rcu(void)
{
@@ -3844,11 +3843,11 @@
/**
* poll_state_synchronize_rcu - Conditionally wait for an RCU grace period
*
- * @oldstate: return from call to get_state_synchronize_rcu() or start_poll_synchronize_rcu()
+ * @oldstate: value from get_state_synchronize_rcu() or start_poll_synchronize_rcu()
*
* If a full RCU grace period has elapsed since the earlier call from
* which oldstate was obtained, return @true, otherwise return @false.
- * If @false is returned, it is the caller's responsibilty to invoke this
+ * If @false is returned, it is the caller's responsibility to invoke this
* function later on until it does return @true. Alternatively, the caller
* can explicitly wait for a grace period, for example, by passing @oldstate
* to cond_synchronize_rcu() or by directly invoking synchronize_rcu().
@@ -3860,6 +3859,11 @@
* (many hours even on 32-bit systems) should check them occasionally
* and either refresh them or set a flag indicating that the grace period
* has completed.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @oldstate, and that returned at the end
+ * of this function.
*/
bool poll_state_synchronize_rcu(unsigned long oldstate)
{
@@ -3874,7 +3878,7 @@
/**
* cond_synchronize_rcu - Conditionally wait for an RCU grace period
*
- * @oldstate: return value from earlier call to get_state_synchronize_rcu()
+ * @oldstate: value from get_state_synchronize_rcu() or start_poll_synchronize_rcu()
*
* If a full RCU grace period has elapsed since the earlier call to
* get_state_synchronize_rcu() or start_poll_synchronize_rcu(), just return.
@@ -3884,6 +3888,11 @@
* counter wrap is harmless. If the counter wraps, we have waited for
* more than 2 billion grace periods (and way more on a 64-bit system!),
* so waiting for one additional grace period should be just fine.
+ *
+ * This function provides the same memory-ordering guarantees that
+ * would be provided by a synchronize_rcu() that was invoked at the call
+ * to the function that provided @oldstate, and that returned at the end
+ * of this function.
*/
void cond_synchronize_rcu(unsigned long oldstate)
{
@@ -3911,7 +3920,7 @@
check_cpu_stall(rdp);
/* Does this CPU need a deferred NOCB wakeup? */
- if (rcu_nocb_need_deferred_wakeup(rdp))
+ if (rcu_nocb_need_deferred_wakeup(rdp, RCU_NOCB_WAKE))
return 1;
/* Is this a nohz_full CPU in userspace or idle? (Ignore RCU if so.) */
@@ -4094,7 +4103,7 @@
/*
* Propagate ->qsinitmask bits up the rcu_node tree to account for the
* first CPU in a given leaf rcu_node structure coming online. The caller
- * must hold the corresponding leaf rcu_node ->lock with interrrupts
+ * must hold the corresponding leaf rcu_node ->lock with interrupts
* disabled.
*/
static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
@@ -4189,7 +4198,7 @@
rdp->rcu_iw_gp_seq = rdp->gp_seq - 1;
trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuonl"));
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
- rcu_prepare_kthreads(cpu);
+ rcu_spawn_one_boost_kthread(rnp);
rcu_spawn_cpu_nocb_kthread(cpu);
WRITE_ONCE(rcu_state.n_online_cpus, rcu_state.n_online_cpus + 1);
@@ -4472,6 +4481,7 @@
wake_up_process(t);
rcu_spawn_nocb_kthreads();
rcu_spawn_boost_kthreads();
+ rcu_spawn_core_kthreads();
return 0;
}
early_initcall(rcu_spawn_gp_kthread);
@@ -4582,11 +4592,25 @@
* replace the definitions in tree.h because those are needed to size
* the ->node array in the rcu_state structure.
*/
-static void __init rcu_init_geometry(void)
+void rcu_init_geometry(void)
{
ulong d;
int i;
+ static unsigned long old_nr_cpu_ids;
int rcu_capacity[RCU_NUM_LVLS];
+ static bool initialized;
+
+ if (initialized) {
+ /*
+ * Warn if setup_nr_cpu_ids() had not yet been invoked,
+ * unless nr_cpus_ids == NR_CPUS, in which case who cares?
+ */
+ WARN_ON_ONCE(old_nr_cpu_ids != nr_cpu_ids);
+ return;
+ }
+
+ old_nr_cpu_ids = nr_cpu_ids;
+ initialized = true;
/*
* Initialize any unspecified boot parameters.
@@ -4687,6 +4711,18 @@
int cpu;
int i;
+ /* Clamp it to [0:100] seconds interval. */
+ if (rcu_delay_page_cache_fill_msec < 0 ||
+ rcu_delay_page_cache_fill_msec > 100 * MSEC_PER_SEC) {
+
+ rcu_delay_page_cache_fill_msec =
+ clamp(rcu_delay_page_cache_fill_msec, 0,
+ (int) (100 * MSEC_PER_SEC));
+
+ pr_info("Adjusting rcutree.rcu_delay_page_cache_fill_msec to %d ms.\n",
+ rcu_delay_page_cache_fill_msec);
+ }
+
for_each_possible_cpu(cpu) {
struct kfree_rcu_cpu *krcp = per_cpu_ptr(&krc, cpu);
@@ -4696,7 +4732,7 @@
}
INIT_DELAYED_WORK(&krcp->monitor_work, kfree_rcu_monitor);
- INIT_WORK(&krcp->page_cache_work, fill_page_cache_func);
+ INIT_DELAYED_WORK(&krcp->page_cache_work, fill_page_cache_func);
krcp->initialized = true;
}
if (register_shrinker(&kfree_rcu_shrinker))
@@ -4730,12 +4766,11 @@
rcutree_online_cpu(cpu);
}
- /* Create workqueue for expedited GPs and for Tree SRCU. */
+ /* Create workqueue for Tree SRCU and for expedited GPs. */
rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_MEM_RECLAIM, 0);
WARN_ON(!rcu_gp_wq);
rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_MEM_RECLAIM, 0);
WARN_ON(!rcu_par_gp_wq);
- srcu_init();
/* Fill in default value for rcutree.qovld boot parameter. */
/* -After- the rcu_node ->lock fields are initialized! */
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 71821d5..305cf6a 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -115,6 +115,7 @@
/* boosting for this rcu_node structure. */
unsigned int boost_kthread_status;
/* State of boost_kthread_task for tracing. */
+ unsigned long n_boosts; /* Number of boosts for this rcu_node structure. */
#ifdef CONFIG_RCU_NOCB_CPU
struct swait_queue_head nocb_gp_wq[2];
/* Place for rcu_nocb_kthread() to wait GP. */
@@ -153,7 +154,7 @@
unsigned long gp_seq; /* Track rsp->gp_seq counter. */
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 core_needs_qs; /* Core waits for quiescent state. */
bool beenonline; /* CPU online at least once. */
bool gpwrap; /* Possible ->gp_seq wrap. */
bool exp_deferred_qs; /* This CPU awaiting a deferred QS? */
@@ -218,7 +219,6 @@
/* 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? */
@@ -257,10 +257,10 @@
};
/* Values for nocb_defer_wakeup field in struct rcu_data. */
-#define RCU_NOCB_WAKE_OFF -1
#define RCU_NOCB_WAKE_NOT 0
-#define RCU_NOCB_WAKE 1
-#define RCU_NOCB_WAKE_FORCE 2
+#define RCU_NOCB_WAKE_BYPASS 1
+#define RCU_NOCB_WAKE 2
+#define RCU_NOCB_WAKE_FORCE 3
#define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
/* For jiffies_till_first_fqs and */
@@ -417,8 +417,8 @@
static void rcu_preempt_boost_start_gp(struct rcu_node *rnp);
static bool rcu_is_callbacks_kthread(void);
static void rcu_cpu_kthread_setup(unsigned int cpu);
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp);
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 bool rcu_preempt_has_tasks(struct rcu_node *rnp);
@@ -434,7 +434,7 @@
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 int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level);
static bool do_nocb_deferred_wakeup(struct rcu_data *rdp);
static void rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp);
static void rcu_spawn_cpu_nocb_kthread(int cpu);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index ad0156b..334eaf4 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -33,10 +33,6 @@
return false;
}
-static inline bool rcu_running_nocb_timer(struct rcu_data *rdp)
-{
- return (timer_curr_running(&rdp->nocb_timer) && !in_irq());
-}
#else
static inline int rcu_lockdep_is_held_nocb(struct rcu_data *rdp)
{
@@ -48,11 +44,6 @@
return false;
}
-static inline bool rcu_running_nocb_timer(struct rcu_data *rdp)
-{
- return false;
-}
-
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
static bool rcu_rdp_is_offloaded(struct rcu_data *rdp)
@@ -72,8 +63,7 @@
rcu_lockdep_is_held_nocb(rdp) ||
(rdp == this_cpu_ptr(&rcu_data) &&
!(IS_ENABLED(CONFIG_PREEMPT_COUNT) && preemptible())) ||
- rcu_current_is_nocb_kthread(rdp) ||
- rcu_running_nocb_timer(rdp)),
+ rcu_current_is_nocb_kthread(rdp)),
"Unsafe read of RCU_NOCB offloaded state"
);
@@ -1098,6 +1088,7 @@
/* Lock only for side effect: boosts task t's priority. */
rt_mutex_lock(&rnp->boost_mtx);
rt_mutex_unlock(&rnp->boost_mtx); /* Then keep lockdep happy. */
+ rnp->n_boosts++;
return READ_ONCE(rnp->exp_tasks) != NULL ||
READ_ONCE(rnp->boost_tasks) != NULL;
@@ -1197,22 +1188,16 @@
*/
static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
{
- int rnp_index = rnp - rcu_get_root();
unsigned long flags;
+ int rnp_index = rnp - rcu_get_root();
struct sched_param sp;
struct task_struct *t;
- if (!IS_ENABLED(CONFIG_PREEMPT_RCU))
- return;
-
- if (!rcu_scheduler_fully_active || rcu_rnp_online_cpus(rnp) == 0)
+ if (rnp->boost_kthread_task || !rcu_scheduler_fully_active)
return;
rcu_state.boost = 1;
- if (rnp->boost_kthread_task != NULL)
- return;
-
t = kthread_create(rcu_boost_kthread, (void *)rnp,
"rcub/%d", rnp_index);
if (WARN_ON_ONCE(IS_ERR(t)))
@@ -1264,17 +1249,8 @@
struct rcu_node *rnp;
rcu_for_each_leaf_node(rnp)
- rcu_spawn_one_boost_kthread(rnp);
-}
-
-static void rcu_prepare_kthreads(int cpu)
-{
- struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
- struct rcu_node *rnp = rdp->mynode;
-
- /* Fire up the incoming CPU's kthread and leaf rcu_node kthread. */
- if (rcu_scheduler_fully_active)
- rcu_spawn_one_boost_kthread(rnp);
+ if (rcu_rnp_online_cpus(rnp))
+ rcu_spawn_one_boost_kthread(rnp);
}
#else /* #ifdef CONFIG_RCU_BOOST */
@@ -1294,6 +1270,10 @@
{
}
+static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
+{
+}
+
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
{
}
@@ -1302,10 +1282,6 @@
{
}
-static void rcu_prepare_kthreads(int cpu)
-{
-}
-
#endif /* #else #ifdef CONFIG_RCU_BOOST */
#if !defined(CONFIG_RCU_FAST_NO_HZ)
@@ -1535,13 +1511,10 @@
static int __init rcu_nocb_setup(char *str)
{
alloc_bootmem_cpumask_var(&rcu_nocb_mask);
- if (!strcasecmp(str, "all")) /* legacy: use "0-N" instead */
+ if (cpulist_parse(str, rcu_nocb_mask)) {
+ pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
cpumask_setall(rcu_nocb_mask);
- else
- if (cpulist_parse(str, rcu_nocb_mask)) {
- pr_warn("rcu_nocbs= bad CPU range, all CPUs set\n");
- cpumask_setall(rcu_nocb_mask);
- }
+ }
return 1;
}
__setup("rcu_nocbs=", rcu_nocb_setup);
@@ -1692,56 +1665,78 @@
return false;
}
-/*
- * Kick the GP kthread for this NOCB group. Caller holds ->nocb_lock
- * and this function releases it.
- */
-static bool wake_nocb_gp(struct rcu_data *rdp, bool force,
- unsigned long flags)
- __releases(rdp->nocb_lock)
+static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
+ struct rcu_data *rdp,
+ bool force, unsigned long flags)
+ __releases(rdp_gp->nocb_gp_lock)
{
bool needwake = false;
- struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
- lockdep_assert_held(&rdp->nocb_lock);
if (!READ_ONCE(rdp_gp->nocb_gp_kthread)) {
- rcu_nocb_unlock_irqrestore(rdp, flags);
+ raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
TPS("AlreadyAwake"));
return false;
}
- if (READ_ONCE(rdp->nocb_defer_wakeup) > RCU_NOCB_WAKE_NOT) {
- WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
- del_timer(&rdp->nocb_timer);
+ if (rdp_gp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) {
+ WRITE_ONCE(rdp_gp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+ del_timer(&rdp_gp->nocb_timer);
}
- rcu_nocb_unlock_irqrestore(rdp, flags);
- raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+
if (force || READ_ONCE(rdp_gp->nocb_gp_sleep)) {
WRITE_ONCE(rdp_gp->nocb_gp_sleep, false);
needwake = true;
- trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DoWake"));
}
raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
- if (needwake)
+ if (needwake) {
+ trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DoWake"));
wake_up_process(rdp_gp->nocb_gp_kthread);
+ }
return needwake;
}
/*
+ * Kick the GP kthread for this NOCB group.
+ */
+static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
+{
+ unsigned long flags;
+ struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+ raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+ return __wake_nocb_gp(rdp_gp, rdp, force, flags);
+}
+
+/*
* Arrange to wake the GP kthread for this NOCB group at some future
* time when it is safe to do so.
*/
static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype,
const char *reason)
{
- if (rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_OFF)
- return;
- if (rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_NOT)
- mod_timer(&rdp->nocb_timer, jiffies + 1);
- if (rdp->nocb_defer_wakeup < waketype)
- WRITE_ONCE(rdp->nocb_defer_wakeup, waketype);
+ unsigned long flags;
+ struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+ raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+
+ /*
+ * Bypass wakeup overrides previous deferments. In case
+ * of callback storm, no need to wake up too early.
+ */
+ if (waketype == RCU_NOCB_WAKE_BYPASS) {
+ mod_timer(&rdp_gp->nocb_timer, jiffies + 2);
+ WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+ } else {
+ if (rdp_gp->nocb_defer_wakeup < RCU_NOCB_WAKE)
+ mod_timer(&rdp_gp->nocb_timer, jiffies + 1);
+ if (rdp_gp->nocb_defer_wakeup < waketype)
+ WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);
+ }
+
+ raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
+
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, reason);
}
@@ -1940,7 +1935,7 @@
}
/*
- * Awaken the no-CBs grace-period kthead if needed, either due to it
+ * Awaken the no-CBs grace-period kthread if needed, either due to it
* legitimately being asleep or due to overload conditions.
*
* If warranted, also wake up the kthread servicing this CPUs queues.
@@ -1968,13 +1963,14 @@
rdp->qlen_last_fqs_check = len;
if (!irqs_disabled_flags(flags)) {
/* ... if queue was empty ... */
- wake_nocb_gp(rdp, false, flags);
+ rcu_nocb_unlock_irqrestore(rdp, flags);
+ wake_nocb_gp(rdp, false);
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
TPS("WakeEmpty"));
} else {
+ rcu_nocb_unlock_irqrestore(rdp, flags);
wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE,
TPS("WakeEmptyIsDeferred"));
- rcu_nocb_unlock_irqrestore(rdp, flags);
}
} else if (len > rdp->qlen_last_fqs_check + qhimark) {
/* ... or if many callbacks queued. */
@@ -1989,10 +1985,14 @@
smp_mb(); /* Enqueue before timer_pending(). */
if ((rdp->nocb_cb_sleep ||
!rcu_segcblist_ready_cbs(&rdp->cblist)) &&
- !timer_pending(&rdp->nocb_bypass_timer))
+ !timer_pending(&rdp->nocb_timer)) {
+ rcu_nocb_unlock_irqrestore(rdp, flags);
wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE_FORCE,
TPS("WakeOvfIsDeferred"));
- rcu_nocb_unlock_irqrestore(rdp, flags);
+ } else {
+ rcu_nocb_unlock_irqrestore(rdp, flags);
+ trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
+ }
} else {
rcu_nocb_unlock_irqrestore(rdp, flags);
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
@@ -2000,18 +2000,6 @@
return;
}
-/* Wake up the no-CBs GP kthread to flush ->nocb_bypass. */
-static void do_nocb_bypass_wakeup_timer(struct timer_list *t)
-{
- unsigned long flags;
- struct rcu_data *rdp = from_timer(rdp, t, nocb_bypass_timer);
-
- trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Timer"));
- rcu_nocb_lock_irqsave(rdp, flags);
- smp_mb__after_spinlock(); /* Timer expire before wakeup. */
- __call_rcu_nocb_wake(rdp, true, flags);
-}
-
/*
* Check if we ignore this rdp.
*
@@ -2118,11 +2106,7 @@
bypass = true;
}
rnp = rdp->mynode;
- if (bypass) { // Avoid race with first bypass CB.
- WRITE_ONCE(my_rdp->nocb_defer_wakeup,
- RCU_NOCB_WAKE_NOT);
- del_timer(&my_rdp->nocb_timer);
- }
+
// Advance callbacks if helpful and low contention.
needwake_gp = false;
if (!rcu_segcblist_restempty(&rdp->cblist,
@@ -2168,12 +2152,12 @@
my_rdp->nocb_gp_bypass = bypass;
my_rdp->nocb_gp_gp = needwait_gp;
my_rdp->nocb_gp_seq = needwait_gp ? wait_gp_seq : 0;
+
if (bypass && !rcu_nocb_poll) {
// At least one child with non-empty ->nocb_bypass, so set
// timer in order to avoid stranding its callbacks.
- raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
- mod_timer(&my_rdp->nocb_bypass_timer, j + 2);
- raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
+ wake_nocb_gp_defer(my_rdp, RCU_NOCB_WAKE_BYPASS,
+ TPS("WakeBypassIsDeferred"));
}
if (rcu_nocb_poll) {
/* Polling, so trace if first poll in the series. */
@@ -2197,8 +2181,10 @@
}
if (!rcu_nocb_poll) {
raw_spin_lock_irqsave(&my_rdp->nocb_gp_lock, flags);
- if (bypass)
- del_timer(&my_rdp->nocb_bypass_timer);
+ if (my_rdp->nocb_defer_wakeup > RCU_NOCB_WAKE_NOT) {
+ WRITE_ONCE(my_rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+ del_timer(&my_rdp->nocb_timer);
+ }
WRITE_ONCE(my_rdp->nocb_gp_sleep, true);
raw_spin_unlock_irqrestore(&my_rdp->nocb_gp_lock, flags);
}
@@ -2334,25 +2320,27 @@
}
/* Is a deferred wakeup of rcu_nocb_kthread() required? */
-static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp)
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
{
- return READ_ONCE(rdp->nocb_defer_wakeup) > RCU_NOCB_WAKE_NOT;
+ return READ_ONCE(rdp->nocb_defer_wakeup) >= level;
}
/* Do a deferred wakeup of rcu_nocb_kthread(). */
-static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp)
+static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
+ struct rcu_data *rdp, int level,
+ unsigned long flags)
+ __releases(rdp_gp->nocb_gp_lock)
{
- unsigned long flags;
int ndw;
int ret;
- rcu_nocb_lock_irqsave(rdp, flags);
- if (!rcu_nocb_need_deferred_wakeup(rdp)) {
- rcu_nocb_unlock_irqrestore(rdp, flags);
+ if (!rcu_nocb_need_deferred_wakeup(rdp_gp, level)) {
+ raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
return false;
}
- ndw = READ_ONCE(rdp->nocb_defer_wakeup);
- ret = wake_nocb_gp(rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
+
+ ndw = rdp_gp->nocb_defer_wakeup;
+ ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
return ret;
@@ -2361,9 +2349,15 @@
/* Do a deferred wakeup of rcu_nocb_kthread() from a timer handler. */
static void do_nocb_deferred_wakeup_timer(struct timer_list *t)
{
+ unsigned long flags;
struct rcu_data *rdp = from_timer(rdp, t, nocb_timer);
- do_nocb_deferred_wakeup_common(rdp);
+ WARN_ON_ONCE(rdp->nocb_gp_rdp != rdp);
+ trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Timer"));
+
+ raw_spin_lock_irqsave(&rdp->nocb_gp_lock, flags);
+ smp_mb__after_spinlock(); /* Timer expire before wakeup. */
+ do_nocb_deferred_wakeup_common(rdp, rdp, RCU_NOCB_WAKE_BYPASS, flags);
}
/*
@@ -2373,9 +2367,14 @@
*/
static bool do_nocb_deferred_wakeup(struct rcu_data *rdp)
{
- if (rcu_nocb_need_deferred_wakeup(rdp))
- return do_nocb_deferred_wakeup_common(rdp);
- return false;
+ unsigned long flags;
+ struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
+
+ if (!rdp_gp || !rcu_nocb_need_deferred_wakeup(rdp_gp, RCU_NOCB_WAKE))
+ return false;
+
+ raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
+ return do_nocb_deferred_wakeup_common(rdp_gp, rdp, RCU_NOCB_WAKE, flags);
}
void rcu_nocb_flush_deferred_wakeup(void)
@@ -2443,17 +2442,15 @@
swait_event_exclusive(rdp->nocb_state_wq,
!rcu_segcblist_test_flags(cblist, SEGCBLIST_KTHREAD_CB |
SEGCBLIST_KTHREAD_GP));
- rcu_nocb_lock_irqsave(rdp, flags);
- /* Make sure nocb timer won't stay around */
- WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_OFF);
- rcu_nocb_unlock_irqrestore(rdp, flags);
- del_timer_sync(&rdp->nocb_timer);
-
/*
- * Theoretically we could set SEGCBLIST_SOFTIRQ_ONLY with CB unlocked
- * and IRQs disabled but let's be paranoid.
+ * Lock one last time to acquire latest callback updates from kthreads
+ * so we can later handle callbacks locally without locking.
*/
rcu_nocb_lock_irqsave(rdp, flags);
+ /*
+ * Theoretically we could set SEGCBLIST_SOFTIRQ_ONLY after the nocb
+ * lock is released but how about being paranoid for once?
+ */
rcu_segcblist_set_flags(cblist, SEGCBLIST_SOFTIRQ_ONLY);
/*
* With SEGCBLIST_SOFTIRQ_ONLY, we can't use
@@ -2473,10 +2470,6 @@
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
int ret = 0;
- if (rdp == rdp->nocb_gp_rdp) {
- pr_info("Can't deoffload an rdp GP leader (yet)\n");
- return -EINVAL;
- }
mutex_lock(&rcu_state.barrier_mutex);
cpus_read_lock();
if (rcu_rdp_is_offloaded(rdp)) {
@@ -2517,8 +2510,7 @@
* SEGCBLIST_SOFTIRQ_ONLY mode.
*/
raw_spin_lock_irqsave(&rdp->nocb_lock, flags);
- /* Re-enable nocb timer */
- WRITE_ONCE(rdp->nocb_defer_wakeup, RCU_NOCB_WAKE_NOT);
+
/*
* We didn't take the nocb lock while working on the
* rdp->cblist in SEGCBLIST_SOFTIRQ_ONLY mode.
@@ -2626,7 +2618,6 @@
raw_spin_lock_init(&rdp->nocb_bypass_lock);
raw_spin_lock_init(&rdp->nocb_gp_lock);
timer_setup(&rdp->nocb_timer, do_nocb_deferred_wakeup_timer, 0);
- timer_setup(&rdp->nocb_bypass_timer, do_nocb_bypass_wakeup_timer, 0);
rcu_cblist_init(&rdp->nocb_bypass);
}
@@ -2785,13 +2776,12 @@
{
struct rcu_node *rnp = rdp->mynode;
- pr_info("nocb GP %d %c%c%c%c%c%c %c[%c%c] %c%c:%ld rnp %d:%d %lu %c CPU %d%s\n",
+ pr_info("nocb GP %d %c%c%c%c%c %c[%c%c] %c%c:%ld rnp %d:%d %lu %c CPU %d%s\n",
rdp->cpu,
"kK"[!!rdp->nocb_gp_kthread],
"lL"[raw_spin_is_locked(&rdp->nocb_gp_lock)],
"dD"[!!rdp->nocb_defer_wakeup],
"tT"[timer_pending(&rdp->nocb_timer)],
- "bB"[timer_pending(&rdp->nocb_bypass_timer)],
"sS"[!!rdp->nocb_gp_sleep],
".W"[swait_active(&rdp->nocb_gp_wq)],
".W"[swait_active(&rnp->nocb_gp_wq[0])],
@@ -2812,7 +2802,6 @@
char bufr[20];
struct rcu_segcblist *rsclp = &rdp->cblist;
bool waslocked;
- bool wastimer;
bool wassleep;
if (rdp->nocb_gp_rdp == rdp)
@@ -2849,15 +2838,13 @@
return;
waslocked = raw_spin_is_locked(&rdp->nocb_gp_lock);
- wastimer = timer_pending(&rdp->nocb_bypass_timer);
wassleep = swait_active(&rdp->nocb_gp_wq);
- if (!rdp->nocb_gp_sleep && !waslocked && !wastimer && !wassleep)
- return; /* Nothing untowards. */
+ if (!rdp->nocb_gp_sleep && !waslocked && !wassleep)
+ return; /* Nothing untoward. */
- pr_info(" nocb GP activity on CB-only CPU!!! %c%c%c%c %c\n",
+ pr_info(" nocb GP activity on CB-only CPU!!! %c%c%c %c\n",
"lL"[waslocked],
"dD"[!!rdp->nocb_defer_wakeup],
- "tT"[wastimer],
"sS"[!!rdp->nocb_gp_sleep],
".W"[wassleep]);
}
@@ -2922,7 +2909,7 @@
{
}
-static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp)
+static int rcu_nocb_need_deferred_wakeup(struct rcu_data *rdp, int level)
{
return false;
}
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 59b95cc..f4152aa 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -314,6 +314,7 @@
* tasks blocked within RCU read-side critical sections.
*/
static int rcu_print_task_stall(struct rcu_node *rnp, unsigned long flags)
+ __releases(rnp->lock)
{
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
return 0;
@@ -717,6 +718,63 @@
/*
+ * Check to see if a failure to end RCU priority inversion was due to
+ * a CPU not passing through a quiescent state. When this happens, there
+ * is nothing that RCU priority boosting can do to help, so we shouldn't
+ * count this as an RCU priority boosting failure. A return of true says
+ * RCU priority boosting is to blame, and false says otherwise. If false
+ * is returned, the first of the CPUs to blame is stored through cpup.
+ * If there was no CPU blocking the current grace period, but also nothing
+ * in need of being boosted, *cpup is set to -1. This can happen in case
+ * of vCPU preemption while the last CPU is reporting its quiscent state,
+ * for example.
+ *
+ * If cpup is NULL, then a lockless quick check is carried out, suitable
+ * for high-rate usage. On the other hand, if cpup is non-NULL, each
+ * rcu_node structure's ->lock is acquired, ruling out high-rate usage.
+ */
+bool rcu_check_boost_fail(unsigned long gp_state, int *cpup)
+{
+ bool atb = false;
+ int cpu;
+ unsigned long flags;
+ struct rcu_node *rnp;
+
+ rcu_for_each_leaf_node(rnp) {
+ if (!cpup) {
+ if (READ_ONCE(rnp->qsmask)) {
+ return false;
+ } else {
+ if (READ_ONCE(rnp->gp_tasks))
+ atb = true;
+ continue;
+ }
+ }
+ *cpup = -1;
+ raw_spin_lock_irqsave_rcu_node(rnp, flags);
+ if (rnp->gp_tasks)
+ atb = true;
+ if (!rnp->qsmask) {
+ // No CPUs without quiescent states for this rnp.
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ continue;
+ }
+ // Find the first holdout CPU.
+ for_each_leaf_node_possible_cpu(rnp, cpu) {
+ if (rnp->qsmask & (1UL << (cpu - rnp->grplo))) {
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ *cpup = cpu;
+ return false;
+ }
+ }
+ raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
+ }
+ // Can't blame CPUs, so must blame RCU priority boosting.
+ return atb;
+}
+EXPORT_SYMBOL_GPL(rcu_check_boost_fail);
+
+/*
* Show the state of the grace-period kthreads.
*/
void show_rcu_gp_kthreads(void)
@@ -726,6 +784,7 @@
unsigned long j;
unsigned long ja;
unsigned long jr;
+ unsigned long js;
unsigned long jw;
struct rcu_data *rdp;
struct rcu_node *rnp;
@@ -734,21 +793,30 @@
j = jiffies;
ja = j - data_race(rcu_state.gp_activity);
jr = j - data_race(rcu_state.gp_req_activity);
+ js = j - data_race(rcu_state.gp_start);
jw = j - data_race(rcu_state.gp_wake_time);
- pr_info("%s: wait state: %s(%d) ->state: %#lx delta ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_flags %#x\n",
+ pr_info("%s: wait state: %s(%d) ->state: %#lx ->rt_priority %u delta ->gp_start %lu ->gp_activity %lu ->gp_req_activity %lu ->gp_wake_time %lu ->gp_wake_seq %ld ->gp_seq %ld ->gp_seq_needed %ld ->gp_max %lu ->gp_flags %#x\n",
rcu_state.name, gp_state_getname(rcu_state.gp_state),
- rcu_state.gp_state, t ? t->state : 0x1ffffL,
- ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq),
+ rcu_state.gp_state, t ? t->state : 0x1ffffL, t ? t->rt_priority : 0xffU,
+ js, ja, jr, jw, (long)data_race(rcu_state.gp_wake_seq),
(long)data_race(rcu_state.gp_seq),
(long)data_race(rcu_get_root()->gp_seq_needed),
+ data_race(rcu_state.gp_max),
data_race(rcu_state.gp_flags));
rcu_for_each_node_breadth_first(rnp) {
- if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq),
- READ_ONCE(rnp->gp_seq_needed)))
+ if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) &&
+ !data_race(rnp->qsmask) && !data_race(rnp->boost_tasks) &&
+ !data_race(rnp->exp_tasks) && !data_race(rnp->gp_tasks))
continue;
- pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld\n",
- rnp->grplo, rnp->grphi, (long)data_race(rnp->gp_seq),
- (long)data_race(rnp->gp_seq_needed));
+ pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n",
+ rnp->grplo, rnp->grphi,
+ (long)data_race(rnp->gp_seq), (long)data_race(rnp->gp_seq_needed),
+ data_race(rnp->qsmask),
+ ".b"[!!data_race(rnp->boost_kthread_task)],
+ ".B"[!!data_race(rnp->boost_tasks)],
+ ".E"[!!data_race(rnp->exp_tasks)],
+ ".G"[!!data_race(rnp->gp_tasks)],
+ data_race(rnp->n_boosts));
if (!rcu_is_leaf_node(rnp))
continue;
for_each_leaf_node_possible_cpu(rnp, cpu) {
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index b95ae86..c21b38c 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -277,7 +277,7 @@
noinstr int notrace debug_lockdep_rcu_enabled(void)
{
- return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && debug_locks &&
+ return rcu_scheduler_active != RCU_SCHEDULER_INACTIVE && READ_ONCE(debug_locks) &&
current->lockdep_recursion == 0;
}
EXPORT_SYMBOL_GPL(debug_lockdep_rcu_enabled);
@@ -524,6 +524,7 @@
}
DEFINE_STATIC_SRCU(early_srcu);
+static unsigned long early_srcu_cookie;
struct early_boot_kfree_rcu {
struct rcu_head rh;
@@ -536,8 +537,10 @@
struct early_boot_kfree_rcu *rhp;
call_rcu(&head, test_callback);
- if (IS_ENABLED(CONFIG_SRCU))
+ if (IS_ENABLED(CONFIG_SRCU)) {
+ early_srcu_cookie = start_poll_synchronize_srcu(&early_srcu);
call_srcu(&early_srcu, &shead, test_callback);
+ }
rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
if (!WARN_ON_ONCE(!rhp))
kfree_rcu(rhp, rh);
@@ -563,6 +566,7 @@
if (IS_ENABLED(CONFIG_SRCU)) {
early_boot_test_counter++;
srcu_barrier(&early_srcu);
+ WARN_ON_ONCE(!poll_state_synchronize_srcu(&early_srcu, early_srcu_cookie));
}
}
if (rcu_self_test_counter != early_boot_test_counter) {
diff --git a/kernel/time/timer.c b/kernel/time/timer.c
index d111adf..84332f0 100644
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -1237,20 +1237,6 @@
}
EXPORT_SYMBOL(try_to_del_timer_sync);
-bool timer_curr_running(struct timer_list *timer)
-{
- int i;
-
- for (i = 0; i < NR_BASES; i++) {
- struct timer_base *base = this_cpu_ptr(&timer_bases[i]);
-
- if (base->running_timer == timer)
- return true;
- }
-
- return false;
-}
-
#ifdef CONFIG_PREEMPT_RT
static __init void timer_base_init_expiry_lock(struct timer_base *base)
{
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 74ceb02..6e29b2aa 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -581,6 +581,14 @@
{
unsigned int lastbit = r->nbits - 1;
+ if (!strncasecmp(str, "all", 3)) {
+ r->start = 0;
+ r->end = lastbit;
+ str += 3;
+
+ goto check_pattern;
+ }
+
str = bitmap_getnum(str, &r->start, lastbit);
if (IS_ERR(str))
return str;
@@ -595,6 +603,7 @@
if (IS_ERR(str))
return str;
+check_pattern:
if (end_of_region(*str))
goto no_pattern;
diff --git a/lib/test_bitmap.c b/lib/test_bitmap.c
index 9cd5755..4ea73f5 100644
--- a/lib/test_bitmap.c
+++ b/lib/test_bitmap.c
@@ -366,6 +366,13 @@
{0, "0-31:1/3,1-31:1/3,2-31:1/3", &exp1[8 * step], 32, 0},
{0, "1-10:8/12,8-31:24/29,0-31:0/3", &exp1[9 * step], 32, 0},
+ {0, "all", &exp1[8 * step], 32, 0},
+ {0, "0, 1, all, ", &exp1[8 * step], 32, 0},
+ {0, "all:1/2", &exp1[4 * step], 32, 0},
+ {0, "ALL:1/2", &exp1[4 * step], 32, 0},
+ {-EINVAL, "al", NULL, 8, 0},
+ {-EINVAL, "alll", NULL, 8, 0},
+
{-EINVAL, "-1", NULL, 8, 0},
{-EINVAL, "-0", NULL, 8, 0},
{-EINVAL, "10-1", NULL, 8, 0},
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index eefd3f5..54527de 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -922,7 +922,7 @@
continue;
}
/*
- * No kthead_use_mm() user needs to read from the userspace so
+ * No kthread_use_mm() user needs to read from the userspace so
* we are ok to reap it.
*/
if (unlikely(p->flags & PF_KTHREAD))
diff --git a/mm/slab.h b/mm/slab.h
index 18c1927..7189daa 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -640,6 +640,7 @@
struct kmem_cache *kp_slab_cache;
void *kp_ret;
void *kp_stack[KS_ADDRS_COUNT];
+ void *kp_free_stack[KS_ADDRS_COUNT];
};
void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
#endif
diff --git a/mm/slab_common.c b/mm/slab_common.c
index f8833d3..92e3aa7 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -564,7 +564,7 @@
* depends on the type of object and on how much debugging is enabled.
* For a slab-cache object, the fact that it is a slab object is printed,
* and, if available, the slab name, return address, and stack trace from
- * the allocation of that object.
+ * the allocation and last free path of that object.
*
* This function will splat if passed a pointer to a non-slab object.
* If you are not sure what type of object you have, you should instead
@@ -609,6 +609,16 @@
break;
pr_info(" %pS\n", kp.kp_stack[i]);
}
+
+ if (kp.kp_free_stack[0])
+ pr_cont(" Free path:\n");
+
+ for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
+ if (!kp.kp_free_stack[i])
+ break;
+ pr_info(" %pS\n", kp.kp_free_stack[i]);
+ }
+
}
EXPORT_SYMBOL_GPL(kmem_dump_obj);
#endif
diff --git a/mm/slub.c b/mm/slub.c
index feda53a..deec894 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4002,6 +4002,7 @@
!(s->flags & SLAB_STORE_USER))
return;
#ifdef CONFIG_SLUB_DEBUG
+ objp = fixup_red_left(s, objp);
trackp = get_track(s, objp, TRACK_ALLOC);
kpp->kp_ret = (void *)trackp->addr;
#ifdef CONFIG_STACKTRACE
@@ -4010,6 +4011,13 @@
if (!kpp->kp_stack[i])
break;
}
+
+ trackp = get_track(s, objp, TRACK_FREE);
+ for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) {
+ kpp->kp_free_stack[i] = (void *)trackp->addrs[i];
+ if (!kpp->kp_free_stack[i])
+ break;
+ }
#endif
#endif
}
diff --git a/mm/util.c b/mm/util.c
index a8bf17f..0b6dd9d 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -983,7 +983,7 @@
* depends on the type of object and on how much debugging is enabled.
* For example, for a slab-cache object, the slab name is printed, and,
* if available, the return address and stack trace from the allocation
- * of that object.
+ * and last free path of that object.
*/
void mem_dump_obj(void *object)
{
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-again.sh b/tools/testing/selftests/rcutorture/bin/kvm-again.sh
index 46e47a0..d8c8483 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-again.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-again.sh
@@ -29,7 +29,7 @@
echo "Usage: $scriptname /path/to/old/run [ options ]"
exit 1
fi
-if ! cp "$oldrun/batches" $T/batches.oldrun
+if ! cp "$oldrun/scenarios" $T/scenarios.oldrun
then
# Later on, can reconstitute this from console.log files.
echo Prior run batches file does not exist: $oldrun/batches
@@ -143,6 +143,8 @@
usage
fi
rm -f "$rundir"/*/{console.log,console.log.diags,qemu_pid,qemu-retval,Warnings,kvm-test-1-run.sh.out,kvm-test-1-run-qemu.sh.out,vmlinux} "$rundir"/log
+touch "$rundir/log"
+echo $scriptname $args | tee -a "$rundir/log"
echo $oldrun > "$rundir/re-run"
if ! test -d "$rundir/../../bin"
then
@@ -165,22 +167,12 @@
grep '^#' $i | sed -e 's/^# //' > $T/qemu-cmd-settings
. $T/qemu-cmd-settings
-grep -v '^#' $T/batches.oldrun | awk '
-BEGIN {
- oldbatch = 1;
-}
-
+grep -v '^#' $T/scenarios.oldrun | awk '
{
- if (oldbatch != $1) {
- print "kvm-test-1-run-batch.sh" curbatch;
- curbatch = "";
- oldbatch = $1;
- }
- curbatch = curbatch " " $2;
-}
-
-END {
- print "kvm-test-1-run-batch.sh" curbatch
+ curbatch = "";
+ for (i = 2; i <= NF; i++)
+ curbatch = curbatch " " $i;
+ print "kvm-test-1-run-batch.sh" curbatch;
}' > $T/runbatches.sh
if test -n "$dryrun"
@@ -188,12 +180,5 @@
echo ---- Dryrun complete, directory: $rundir | tee -a "$rundir/log"
else
( cd "$rundir"; sh $T/runbatches.sh )
- kcsan-collapse.sh "$rundir" | tee -a "$rundir/log"
- echo | tee -a "$rundir/log"
- echo ---- Results directory: $rundir | tee -a "$rundir/log"
- kvm-recheck.sh "$rundir" > $T/kvm-recheck.sh.out 2>&1
- ret=$?
- cat $T/kvm-recheck.sh.out | tee -a "$rundir/log"
- echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a "$rundir/log"
- exit $ret
+ kvm-end-run-stats.sh "$rundir" "$starttime"
fi
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-build.sh b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
index 115e182..5ad973d 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-build.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-build.sh
@@ -40,8 +40,10 @@
then
exit 2
fi
-ncpus=`cpus2use.sh`
-make -j$ncpus $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
+
+# Tell "make" to use double the number of real CPUs on the build system.
+ncpus="`getconf _NPROCESSORS_ONLN`"
+make -j$((2 * ncpus)) $TORTURE_KMAKE_ARG > $resdir/Make.out 2>&1
retval=$?
if test $retval -ne 0 || grep "rcu[^/]*": < $resdir/Make.out | egrep -q "Stop|Error|error:|warning:" || egrep -q "Stop|Error|error:" < $resdir/Make.out
then
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-end-run-stats.sh b/tools/testing/selftests/rcutorture/bin/kvm-end-run-stats.sh
new file mode 100755
index 0000000..e4a0077
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/kvm-end-run-stats.sh
@@ -0,0 +1,40 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Check the status of the specified run.
+#
+# Usage: kvm-end-run-stats.sh /path/to/run starttime
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+# scriptname=$0
+# args="$*"
+rundir="$1"
+if ! test -d "$rundir"
+then
+ echo kvm-end-run-stats.sh: Specified run directory does not exist: $rundir
+ exit 1
+fi
+
+T=${TMPDIR-/tmp}/kvm-end-run-stats.sh.$$
+trap 'rm -rf $T' 0
+mkdir $T
+
+KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
+PATH=${KVM}/bin:$PATH; export PATH
+. functions.sh
+default_starttime="`get_starttime`"
+starttime="${2-default_starttime}"
+
+echo | tee -a "$rundir/log"
+echo | tee -a "$rundir/log"
+echo " --- `date` Test summary:" | tee -a "$rundir/log"
+echo Results directory: $rundir | tee -a "$rundir/log"
+kcsan-collapse.sh "$rundir" | tee -a "$rundir/log"
+kvm-recheck.sh "$rundir" > $T/kvm-recheck.sh.out 2>&1
+ret=$?
+cat $T/kvm-recheck.sh.out | tee -a "$rundir/log"
+echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a "$rundir/log"
+exit $ret
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh b/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
index 0670841..daf64b5 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-find-errors.sh
@@ -43,7 +43,7 @@
else
echo No build errors.
fi
-if grep -q -e "--buildonly" < ${rundir}/log
+if grep -q -e "--build-\?only" < ${rundir}/log && ! test -f "${rundir}/remote-log"
then
echo Build-only run, no console logs to check.
exit $editorret
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
index 1706cd4..fbdf162 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm-recheck-rcu.sh
@@ -31,7 +31,7 @@
echo "$configfile ------- " $stopstate
else
title="$configfile ------- $ngps GPs"
- dur=`sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//' < $i/qemu-cmd 2> /dev/null`
+ dur=`grep -v '^#' $i/qemu-cmd | sed -e 's/^.* rcutorture.shutdown_secs=//' -e 's/ .*$//'`
if test -z "$dur"
then
:
diff --git a/tools/testing/selftests/rcutorture/bin/kvm-remote.sh b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
new file mode 100755
index 0000000..79e680e
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/bin/kvm-remote.sh
@@ -0,0 +1,249 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+
+#
+# Run a series of tests on remote systems under KVM.
+#
+# Usage: kvm-remote.sh "systems" [ <kvm.sh args> ]
+# kvm-remote.sh "systems" /path/to/old/run [ <kvm-again.sh args> ]
+#
+# Copyright (C) 2021 Facebook, Inc.
+#
+# Authors: Paul E. McKenney <paulmck@kernel.org>
+
+scriptname=$0
+args="$*"
+
+if ! test -d tools/testing/selftests/rcutorture/bin
+then
+ echo $scriptname must be run from top-level directory of kernel source tree.
+ exit 1
+fi
+
+KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
+PATH=${KVM}/bin:$PATH; export PATH
+. functions.sh
+
+starttime="`get_starttime`"
+
+systems="$1"
+if test -z "$systems"
+then
+ echo $scriptname: Empty list of systems will go nowhere good, giving up.
+ exit 1
+fi
+shift
+
+# Pathnames:
+# T: /tmp/kvm-remote.sh.$$
+# resdir: /tmp/kvm-remote.sh.$$/res
+# rundir: /tmp/kvm-remote.sh.$$/res/$ds ("-remote" suffix)
+# oldrun: `pwd`/tools/testing/.../res/$otherds
+#
+# Pathname segments:
+# TD: kvm-remote.sh.$$
+# ds: yyyy.mm.dd-hh.mm.ss-remote
+
+TD=kvm-remote.sh.$$
+T=${TMPDIR-/tmp}/$TD
+trap 'rm -rf $T' 0
+mkdir $T
+
+resdir="$T/res"
+ds=`date +%Y.%m.%d-%H.%M.%S`-remote
+rundir=$resdir/$ds
+echo Results directory: $rundir
+echo $scriptname $args
+if echo $1 | grep -q '^--'
+then
+ # Fresh build. Create a datestamp unless the caller supplied one.
+ datestamp="`echo "$@" | awk -v ds="$ds" '{
+ for (i = 1; i < NF; i++) {
+ if ($i == "--datestamp") {
+ ds = "";
+ break;
+ }
+ }
+ if (ds != "")
+ print "--datestamp " ds;
+ }'`"
+ kvm.sh --remote "$@" $datestamp --buildonly > $T/kvm.sh.out 2>&1
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo $scriptname: kvm.sh failed exit code $?
+ cat $T/kvm.sh.out
+ exit 2
+ fi
+ oldrun="`grep -m 1 "^Results directory: " $T/kvm.sh.out | awk '{ print $3 }'`"
+ touch "$oldrun/remote-log"
+ echo $scriptname $args >> "$oldrun/remote-log"
+ echo | tee -a "$oldrun/remote-log"
+ echo " ----" kvm.sh output: "(`date`)" | tee -a "$oldrun/remote-log"
+ cat $T/kvm.sh.out | tee -a "$oldrun/remote-log"
+ # We are going to run this, so remove the buildonly files.
+ rm -f "$oldrun"/*/buildonly
+ kvm-again.sh $oldrun --dryrun --remote --rundir "$rundir" > $T/kvm-again.sh.out 2>&1
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo $scriptname: kvm-again.sh failed exit code $? | tee -a "$oldrun/remote-log"
+ cat $T/kvm-again.sh.out | tee -a "$oldrun/remote-log"
+ exit 2
+ fi
+else
+ # Re-use old run.
+ oldrun="$1"
+ if ! echo $oldrun | grep -q '^/'
+ then
+ oldrun="`pwd`/$oldrun"
+ fi
+ shift
+ touch "$oldrun/remote-log"
+ echo $scriptname $args >> "$oldrun/remote-log"
+ kvm-again.sh "$oldrun" "$@" --dryrun --remote --rundir "$rundir" > $T/kvm-again.sh.out 2>&1
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo $scriptname: kvm-again.sh failed exit code $? | tee -a "$oldrun/remote-log"
+ cat $T/kvm-again.sh.out | tee -a "$oldrun/remote-log"
+ exit 2
+ fi
+ cp -a "$rundir" "$KVM/res/"
+ oldrun="$KVM/res/$ds"
+fi
+echo | tee -a "$oldrun/remote-log"
+echo " ----" kvm-again.sh output: "(`date`)" | tee -a "$oldrun/remote-log"
+cat $T/kvm-again.sh.out
+echo | tee -a "$oldrun/remote-log"
+echo Remote run directory: $rundir | tee -a "$oldrun/remote-log"
+echo Local build-side run directory: $oldrun | tee -a "$oldrun/remote-log"
+
+# Create the kvm-remote-N.sh scripts in the bin directory.
+awk < "$rundir"/scenarios -v dest="$T/bin" -v rundir="$rundir" '
+{
+ n = $1;
+ sub(/\./, "", n);
+ fn = dest "/kvm-remote-" n ".sh"
+ scenarios = "";
+ for (i = 2; i <= NF; i++)
+ scenarios = scenarios " " $i;
+ print "kvm-test-1-run-batch.sh" scenarios > fn;
+ print "rm " rundir "/remote.run" >> fn;
+}'
+chmod +x $T/bin/kvm-remote-*.sh
+( cd "`dirname $T`"; tar -chzf $T/binres.tgz "$TD/bin" "$TD/res" )
+
+# Check first to avoid the need for cleanup for system-name typos
+for i in $systems
+do
+ ncpus="`ssh $i getconf _NPROCESSORS_ONLN 2> /dev/null`"
+ echo $i: $ncpus CPUs " " `date` | tee -a "$oldrun/remote-log"
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo System $i unreachable, giving up. | tee -a "$oldrun/remote-log"
+ exit 4 | tee -a "$oldrun/remote-log"
+ fi
+done
+
+# Download and expand the tarball on all systems.
+for i in $systems
+do
+ echo Downloading tarball to $i `date` | tee -a "$oldrun/remote-log"
+ cat $T/binres.tgz | ssh $i "cd /tmp; tar -xzf -"
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo Unable to download $T/binres.tgz to system $i, giving up. | tee -a "$oldrun/remote-log"
+ exit 10 | tee -a "$oldrun/remote-log"
+ fi
+done
+
+# Function to check for presence of a file on the specified system.
+# Complain if the system cannot be reached, and retry after a wait.
+# Currently just waits forever if a machine disappears.
+#
+# Usage: checkremotefile system pathname
+checkremotefile () {
+ local ret
+ local sleeptime=60
+
+ while :
+ do
+ ssh $1 "test -f \"$2\""
+ ret=$?
+ if test "$ret" -ne 255
+ then
+ return $ret
+ fi
+ echo " ---" ssh failure to $1 checking for file $2, retry after $sleeptime seconds. `date`
+ sleep $sleeptime
+ done
+}
+
+# Function to start batches on idle remote $systems
+#
+# Usage: startbatches curbatch nbatches
+#
+# Batches are numbered starting at 1. Returns the next batch to start.
+# Be careful to redirect all debug output to FD 2 (stderr).
+startbatches () {
+ local curbatch="$1"
+ local nbatches="$2"
+ local ret
+
+ # Each pass through the following loop examines one system.
+ for i in $systems
+ do
+ if test "$curbatch" -gt "$nbatches"
+ then
+ echo $((nbatches + 1))
+ return 0
+ fi
+ if checkremotefile "$i" "$resdir/$ds/remote.run" 1>&2
+ then
+ continue # System still running last test, skip.
+ fi
+ ssh "$i" "cd \"$resdir/$ds\"; touch remote.run; PATH=\"$T/bin:$PATH\" nohup kvm-remote-$curbatch.sh > kvm-remote-$curbatch.sh.out 2>&1 &" 1>&2
+ ret=$?
+ if test "$ret" -ne 0
+ then
+ echo ssh $i failed: exitcode $ret 1>&2
+ exit 11
+ fi
+ echo " ----" System $i Batch `head -n $curbatch < "$rundir"/scenarios | tail -1` `date` 1>&2
+ curbatch=$((curbatch + 1))
+ done
+ echo $curbatch
+}
+
+# Launch all the scenarios.
+nbatches="`wc -l "$rundir"/scenarios | awk '{ print $1 }'`"
+curbatch=1
+while test "$curbatch" -le "$nbatches"
+do
+ startbatches $curbatch $nbatches > $T/curbatch 2> $T/startbatches.stderr
+ curbatch="`cat $T/curbatch`"
+ if test -s "$T/startbatches.stderr"
+ then
+ cat "$T/startbatches.stderr" | tee -a "$oldrun/remote-log"
+ fi
+ if test "$curbatch" -le "$nbatches"
+ then
+ sleep 30
+ fi
+done
+echo All batches started. `date`
+
+# Wait for all remaining scenarios to complete and collect results.
+for i in $systems
+do
+ while checkremotefile "$i" "$resdir/$ds/remote.run"
+ do
+ sleep 30
+ done
+ ( cd "$oldrun"; ssh $i "cd $rundir; tar -czf - kvm-remote-*.sh.out */console.log */kvm-test-1-run*.sh.out */qemu_pid */qemu-retval; rm -rf $T > /dev/null 2>&1" | tar -xzf - )
+done
+
+( kvm-end-run-stats.sh "$oldrun" "$starttime"; echo $? > $T/exitcode ) | tee -a "$oldrun/remote-log"
+exit "`cat $T/exitcode`"
diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh
index 6bf00a0..b4ac4ee3 100755
--- a/tools/testing/selftests/rcutorture/bin/kvm.sh
+++ b/tools/testing/selftests/rcutorture/bin/kvm.sh
@@ -20,6 +20,9 @@
cd `dirname $scriptname`/../../../../../
+# This script knows only English.
+LANG=en_US.UTF-8; export LANG
+
dur=$((30*60))
dryrun=""
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
@@ -41,6 +44,7 @@
TORTURE_KCONFIG_KCSAN_ARG=""
TORTURE_KMAKE_ARG=""
TORTURE_QEMU_MEM=512
+TORTURE_REMOTE=
TORTURE_SHUTDOWN_GRACE=180
TORTURE_SUITE=rcu
TORTURE_MOD=rcutorture
@@ -64,7 +68,7 @@
echo " --cpus N"
echo " --datestamp string"
echo " --defconfig string"
- echo " --dryrun batches|sched|script"
+ echo " --dryrun batches|scenarios|sched|script"
echo " --duration minutes | <seconds>s | <hours>h | <days>d"
echo " --gdb"
echo " --help"
@@ -77,6 +81,7 @@
echo " --no-initrd"
echo " --qemu-args qemu-arguments"
echo " --qemu-cmd qemu-system-..."
+ echo " --remote"
echo " --results absolute-pathname"
echo " --torture lock|rcu|rcuscale|refscale|scf"
echo " --trust-make"
@@ -112,10 +117,13 @@
checkarg --cpus "(number)" "$#" "$2" '^[0-9]*$' '^--'
cpus=$2
TORTURE_ALLOTED_CPUS="$2"
- max_cpus="`identify_qemu_vcpus`"
- if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus"
+ if test -z "$TORTURE_REMOTE"
then
- TORTURE_ALLOTED_CPUS=$max_cpus
+ max_cpus="`identify_qemu_vcpus`"
+ if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus"
+ then
+ TORTURE_ALLOTED_CPUS=$max_cpus
+ fi
fi
shift
;;
@@ -130,7 +138,7 @@
shift
;;
--dryrun)
- checkarg --dryrun "batches|sched|script" $# "$2" 'batches\|sched\|script' '^--'
+ checkarg --dryrun "batches|sched|script" $# "$2" 'batches\|scenarios\|sched\|script' '^--'
dryrun=$2
shift
;;
@@ -206,6 +214,9 @@
TORTURE_QEMU_CMD="$2"
shift
;;
+ --remote)
+ TORTURE_REMOTE=1
+ ;;
--results)
checkarg --results "(absolute pathname)" "$#" "$2" '^/' '^error'
resdir=$2
@@ -550,20 +561,7 @@
if (ncpus != 0)
dump(first, i, batchnum);
}' >> $T/script
-
-cat << '___EOF___' >> $T/script
-echo | tee -a $TORTURE_RESDIR/log
-echo | tee -a $TORTURE_RESDIR/log
-echo " --- `date` Test summary:" | tee -a $TORTURE_RESDIR/log
-___EOF___
-cat << ___EOF___ >> $T/script
-echo Results directory: $resdir/$ds | tee -a $resdir/$ds/log
-kcsan-collapse.sh $resdir/$ds | tee -a $resdir/$ds/log
-kvm-recheck.sh $resdir/$ds > $T/kvm-recheck.sh.out 2>&1
-___EOF___
-echo 'ret=$?' >> $T/script
-echo "cat $T/kvm-recheck.sh.out | tee -a $resdir/$ds/log" >> $T/script
-echo 'exit $ret' >> $T/script
+echo kvm-end-run-stats.sh "$resdir/$ds" "$starttime" >> $T/script
# Extract the tests and their batches from the script.
egrep 'Start batch|Starting build\.' $T/script | grep -v ">>" |
@@ -577,6 +575,25 @@
print batchno, $1, $2
}' > $T/batches
+# As above, but one line per batch.
+grep -v '^#' $T/batches | awk '
+BEGIN {
+ oldbatch = 1;
+}
+
+{
+ if (oldbatch != $1) {
+ print ++n ". " curbatch;
+ curbatch = "";
+ oldbatch = $1;
+ }
+ curbatch = curbatch " " $2;
+}
+
+END {
+ print ++n ". " curbatch;
+}' > $T/scenarios
+
if test "$dryrun" = script
then
cat $T/script
@@ -597,13 +614,17 @@
then
cat $T/batches
exit 0
+elif test "$dryrun" = scenarios
+then
+ cat $T/scenarios
+ exit 0
else
# Not a dryrun. Record the batches and the number of CPUs, then run the script.
bash $T/script
ret=$?
cp $T/batches $resdir/$ds/batches
+ cp $T/scenarios $resdir/$ds/scenarios
echo '#' cpus=$cpus >> $resdir/$ds/batches
- echo " --- Done at `date` (`get_starttime_duration $starttime`) exitcode $ret" | tee -a $resdir/$ds/log
exit $ret
fi
diff --git a/tools/testing/selftests/rcutorture/bin/torture.sh b/tools/testing/selftests/rcutorture/bin/torture.sh
index 56e2e1a..53ec7c0 100755
--- a/tools/testing/selftests/rcutorture/bin/torture.sh
+++ b/tools/testing/selftests/rcutorture/bin/torture.sh
@@ -302,7 +302,7 @@
kcsan_kmake_tag="--kmake-args"
cur_kcsan_kmake_args="$kcsan_kmake_args"
fi
- torture_one $* --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" $kcsan_kmake_tag $cur_kcsan_kmake_args --kcsan
+ torture_one "$@" --kconfig "CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_PROVE_LOCKING=y" $kcsan_kmake_tag $cur_kcsan_kmake_args --kcsan
fi
}
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST
new file mode 100644
index 0000000..22d598f
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST
@@ -0,0 +1,17 @@
+CONFIG_SMP=y
+CONFIG_NR_CPUS=16
+CONFIG_PREEMPT_NONE=n
+CONFIG_PREEMPT_VOLUNTARY=n
+CONFIG_PREEMPT=y
+#CHECK#CONFIG_PREEMPT_RCU=y
+CONFIG_HZ_PERIODIC=y
+CONFIG_NO_HZ_IDLE=n
+CONFIG_NO_HZ_FULL=n
+CONFIG_RCU_TRACE=y
+CONFIG_HOTPLUG_CPU=y
+CONFIG_RCU_FANOUT=2
+CONFIG_RCU_FANOUT_LEAF=2
+CONFIG_RCU_NOCB_CPU=n
+CONFIG_DEBUG_LOCK_ALLOC=n
+CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
+CONFIG_RCU_EXPERT=y
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot
new file mode 100644
index 0000000..f57720c
--- /dev/null
+++ b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot
@@ -0,0 +1,8 @@
+rcutorture.test_boost=2
+rcutorture.stutter=0
+rcutree.gp_preinit_delay=12
+rcutree.gp_init_delay=3
+rcutree.gp_cleanup_delay=3
+rcutree.kthread_prio=2
+threadirqs
+tree.use_softirq=0
diff --git a/tools/testing/selftests/rcutorture/configs/rcuscale/TREE b/tools/testing/selftests/rcutorture/configs/rcuscale/TREE
index 721cfda..4cc1cc5 100644
--- a/tools/testing/selftests/rcutorture/configs/rcuscale/TREE
+++ b/tools/testing/selftests/rcutorture/configs/rcuscale/TREE
@@ -7,7 +7,7 @@
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_NOCB_CPU=n
diff --git a/tools/testing/selftests/rcutorture/configs/rcuscale/TREE54 b/tools/testing/selftests/rcutorture/configs/rcuscale/TREE54
index 7629f5d..f595206 100644
--- a/tools/testing/selftests/rcutorture/configs/rcuscale/TREE54
+++ b/tools/testing/selftests/rcutorture/configs/rcuscale/TREE54
@@ -8,7 +8,7 @@
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_FANOUT=3
diff --git a/tools/testing/selftests/rcutorture/configs/refscale/NOPREEMPT b/tools/testing/selftests/rcutorture/configs/refscale/NOPREEMPT
index 1cd25b7..ad505a8 100644
--- a/tools/testing/selftests/rcutorture/configs/refscale/NOPREEMPT
+++ b/tools/testing/selftests/rcutorture/configs/refscale/NOPREEMPT
@@ -7,7 +7,7 @@
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_NOCB_CPU=n
diff --git a/tools/testing/selftests/rcutorture/configs/refscale/PREEMPT b/tools/testing/selftests/rcutorture/configs/refscale/PREEMPT
index d10bc69..4f08e64 100644
--- a/tools/testing/selftests/rcutorture/configs/refscale/PREEMPT
+++ b/tools/testing/selftests/rcutorture/configs/refscale/PREEMPT
@@ -7,7 +7,7 @@
CONFIG_NO_HZ_IDLE=y
CONFIG_NO_HZ_FULL=n
CONFIG_RCU_FAST_NO_HZ=n
-CONFIG_HOTPLUG_CPU=n
+CONFIG_HOTPLUG_CPU=y
CONFIG_SUSPEND=n
CONFIG_HIBERNATION=n
CONFIG_RCU_NOCB_CPU=n
diff --git a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h
index cf6938d..1e24827 100644
--- a/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h
+++ b/tools/testing/selftests/rcutorture/formal/srcu-cbmc/src/locks.h
@@ -174,7 +174,7 @@
}
struct completion {
- /* Hopefuly this won't overflow. */
+ /* Hopefully this won't overflow. */
unsigned int count;
};
