Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Merge commit. Changes below are compared with the first parent: ceee0e95.
Changes
19 files changed · +669 −590
| File | Status | Add | Del | Content |
|---|---|---|---|---|
| Documentation/RCU/checklist.txt | modified | +20 | −19 | View file |
| Documentation/RCU/rcubarrier.txt | modified | +4 | −11 | View file |
| Documentation/RCU/torture.txt | modified | +9 | −0 | View file |
| Documentation/RCU/whatisRCU.txt | modified | +3 | −3 | View file |
| Documentation/kernel-parameters.txt | modified | +5 | −0 | View file |
| include/linux/init_task.h | modified | +2 | −2 | View file |
| include/linux/key.h | modified | +3 | −1 | View file |
| include/linux/rcupdate.h | modified | +20 | −33 | View file |
| include/trace/events/rcu.h | modified | +45 | −0 | View file |
| kernel/rcupdate.c | modified | +44 | −0 | View file |
| kernel/rcutiny.c | modified | +2 | −2 | View file |
| kernel/rcutiny_plugin.h | modified | +5 | −51 | View file |
| kernel/rcutorture.c | modified | +44 | −28 | View file |
| kernel/rcutree.c | modified | +309 | −169 | View file |
| kernel/rcutree.h | modified | +29 | −17 | View file |
| kernel/rcutree_plugin.h | modified | +44 | −179 | View file |
| kernel/rcutree_trace.c | modified | +78 | −70 | View file |
| kernel/time/tick-sched.c | modified | +1 | −1 | View file |
| lib/list_debug.c | modified | +2 | −4 | View file |
Only the first 600 diff lines are shown. Download the complete patch.
Documentation/RCU/checklist.txt
View filediff --git a/Documentation/RCU/checklist.txt b/Documentation/RCU/checklist.txt
index 5c8d749..fc103d7 100644
--- a/Documentation/RCU/checklist.txt
+++ b/Documentation/RCU/checklist.txt
@@ -162,9 +162,9 @@ over a rather long period of time, but improvements are always welcome!
when publicizing a pointer to a structure that can
be traversed by an RCU read-side critical section.
-5. If call_rcu(), or a related primitive such as call_rcu_bh() or
- call_rcu_sched(), is used, the callback function must be
- written to be called from softirq context. In particular,
+5. If call_rcu(), or a related primitive such as call_rcu_bh(),
+ call_rcu_sched(), or call_srcu() is used, the callback function
+ must be written to be called from softirq context. In particular,
it cannot block.
6. Since synchronize_rcu() can block, it cannot be called from
@@ -202,11 +202,12 @@ over a rather long period of time, but improvements are always welcome!
updater uses call_rcu_sched() or synchronize_sched(), then
the corresponding readers must disable preemption, possibly
by calling rcu_read_lock_sched() and rcu_read_unlock_sched().
- If the updater uses synchronize_srcu(), the the corresponding
- readers must use srcu_read_lock() and srcu_read_unlock(),
- and with the same srcu_struct. The rules for the expedited
- primitives are the same as for their non-expedited counterparts.
- Mixing things up will result in confusion and broken kernels.
+ If the updater uses synchronize_srcu() or call_srcu(),
+ the the corresponding readers must use srcu_read_lock() and
+ srcu_read_unlock(), and with the same srcu_struct. The rules for
+ the expedited primitives are the same as for their non-expedited
+ counterparts. Mixing things up will result in confusion and
+ broken kernels.
One exception to this rule: rcu_read_lock() and rcu_read_unlock()
may be substituted for rcu_read_lock_bh() and rcu_read_unlock_bh()
@@ -333,14 +334,14 @@ over a rather long period of time, but improvements are always welcome!
victim CPU from ever going offline.)
14. SRCU (srcu_read_lock(), srcu_read_unlock(), srcu_dereference(),
- synchronize_srcu(), and synchronize_srcu_expedited()) may only
- be invoked from process context. Unlike other forms of RCU, it
- -is- permissible to block in an SRCU read-side critical section
- (demarked by srcu_read_lock() and srcu_read_unlock()), hence the
- "SRCU": "sleepable RCU". Please note that if you don't need
- to sleep in read-side critical sections, you should be using
- RCU rather than SRCU, because RCU is almost always faster and
- easier to use than is SRCU.
+ synchronize_srcu(), synchronize_srcu_expedited(), and call_srcu())
+ may only be invoked from process context. Unlike other forms of
+ RCU, it -is- permissible to block in an SRCU read-side critical
+ section (demarked by srcu_read_lock() and srcu_read_unlock()),
+ hence the "SRCU": "sleepable RCU". Please note that if you
+ don't need to sleep in read-side critical sections, you should be
+ using RCU rather than SRCU, because RCU is almost always faster
+ and easier to use than is SRCU.
If you need to enter your read-side critical section in a
hardirq or exception handler, and then exit that same read-side
@@ -353,8 +354,8 @@ over a rather long period of time, but improvements are always welcome!
cleanup_srcu_struct(). These are passed a "struct srcu_struct"
that defines the scope of a given SRCU domain. Once initialized,
the srcu_struct is passed to srcu_read_lock(), srcu_read_unlock()
- synchronize_srcu(), and synchronize_srcu_expedited(). A given
- synchronize_srcu() waits only for SRCU read-side critical
+ synchronize_srcu(), synchronize_srcu_expedited(), and call_srcu().
+ A given synchronize_srcu() waits only for SRCU read-side critical
sections governed by srcu_read_lock() and srcu_read_unlock()
calls that have been passed the same srcu_struct. This property
is what makes sleeping read-side critical sections tolerable --
@@ -374,7 +375,7 @@ over a rather long period of time, but improvements are always welcome!
requiring SRCU's read-side deadlock immunity or low read-side
realtime latency.
- Note that, rcu_assign_pointer() relates to SRCU just as they do
+ Note that, rcu_assign_pointer() relates to SRCU just as it does
to other forms of RCU.
15. The whole point of call_rcu(), synchronize_rcu(), and friends
Documentation/RCU/rcubarrier.txt
View filediff --git a/Documentation/RCU/rcubarrier.txt b/Documentation/RCU/rcubarrier.txt
index e439a0e..38428c1 100644
--- a/Documentation/RCU/rcubarrier.txt
+++ b/Documentation/RCU/rcubarrier.txt
@@ -79,8 +79,6 @@ complete. Pseudo-code using rcu_barrier() is as follows:
2. Execute rcu_barrier().
3. Allow the module to be unloaded.
-Quick Quiz #1: Why is there no srcu_barrier()?
-
The rcutorture module makes use of rcu_barrier in its exit function
as follows:
@@ -162,7 +160,7 @@ for any pre-existing callbacks to complete.
Then lines 55-62 print status and do operation-specific cleanup, and
then return, permitting the module-unload operation to be completed.
-Quick Quiz #2: Is there any other situation where rcu_barrier() might
+Quick Quiz #1: Is there any other situation where rcu_barrier() might
be required?
Your module might have additional complications. For example, if your
@@ -242,7 +240,7 @@ reaches zero, as follows:
4 complete(&rcu_barrier_completion);
5 }
-Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes
+Quick Quiz #2: What happens if CPU 0's rcu_barrier_func() executes
immediately (thus incrementing rcu_barrier_cpu_count to the
value one), but the other CPU's rcu_barrier_func() invocations
are delayed for a full grace period? Couldn't this result in
@@ -259,12 +257,7 @@ so that your module may be safely unloaded.
Answers to Quick Quizzes
-Quick Quiz #1: Why is there no srcu_barrier()?
-
-Answer: Since there is no call_srcu(), there can be no outstanding SRCU
- callbacks. Therefore, there is no need to wait for them.
-
-Quick Quiz #2: Is there any other situation where rcu_barrier() might
+Quick Quiz #1: Is there any other situation where rcu_barrier() might
be required?
Answer: Interestingly enough, rcu_barrier() was not originally
@@ -278,7 +271,7 @@ Answer: Interestingly enough, rcu_barrier() was not originally
implementing rcutorture, and found that rcu_barrier() solves
this problem as well.
-Quick Quiz #3: What happens if CPU 0's rcu_barrier_func() executes
+Quick Quiz #2: What happens if CPU 0's rcu_barrier_func() executes
immediately (thus incrementing rcu_barrier_cpu_count to the
value one), but the other CPU's rcu_barrier_func() invocations
are delayed for a full grace period? Couldn't this result in
Documentation/RCU/torture.txt
View filediff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 4ddf391..7dce8a1 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -174,11 +174,20 @@ torture_type The type of RCU to test, with string values as follows:
and synchronize_rcu_bh_expedited().
"srcu": srcu_read_lock(), srcu_read_unlock() and
+ call_srcu().
+
+ "srcu_sync": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu().
"srcu_expedited": srcu_read_lock(), srcu_read_unlock() and
synchronize_srcu_expedited().
+ "srcu_raw": srcu_read_lock_raw(), srcu_read_unlock_raw(),
+ and call_srcu().
+
+ "srcu_raw_sync": srcu_read_lock_raw(), srcu_read_unlock_raw(),
+ and synchronize_srcu().
+
"sched": preempt_disable(), preempt_enable(), and
call_rcu_sched().
Documentation/RCU/whatisRCU.txt
View filediff --git a/Documentation/RCU/whatisRCU.txt b/Documentation/RCU/whatisRCU.txt
index 6bbe8dc..69ee188 100644
--- a/Documentation/RCU/whatisRCU.txt
+++ b/Documentation/RCU/whatisRCU.txt
@@ -833,9 +833,9 @@ sched: Critical sections Grace period Barrier
SRCU: Critical sections Grace period Barrier
- srcu_read_lock synchronize_srcu N/A
- srcu_read_unlock synchronize_srcu_expedited
- srcu_read_lock_raw
+ srcu_read_lock synchronize_srcu srcu_barrier
+ srcu_read_unlock call_srcu
+ srcu_read_lock_raw synchronize_srcu_expedited
srcu_read_unlock_raw
srcu_dereference
Documentation/kernel-parameters.txt
View filediff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index a92c5eb..12783fa 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2367,6 +2367,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Set maximum number of finished RCU callbacks to process
in one batch.
+ rcutree.fanout_leaf= [KNL,BOOT]
+ Increase the number of CPUs assigned to each
+ leaf rcu_node structure. Useful for very large
+ systems.
+
rcutree.qhimark= [KNL,BOOT]
Set threshold of queued
RCU callbacks over which batch limiting is disabled.
include/linux/init_task.h
View filediff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 9e65eff..8a74761 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -168,8 +168,8 @@ extern struct cred init_cred;
.children = LIST_HEAD_INIT(tsk.children), \
.sibling = LIST_HEAD_INIT(tsk.sibling), \
.group_leader = &tsk, \
- RCU_INIT_POINTER(.real_cred, &init_cred), \
- RCU_INIT_POINTER(.cred, &init_cred), \
+ RCU_POINTER_INITIALIZER(real_cred, &init_cred), \
+ RCU_POINTER_INITIALIZER(cred, &init_cred), \
.comm = INIT_TASK_COMM, \
.thread = INIT_THREAD, \
.fs = &init_fs, \
include/linux/key.h
View filediff --git a/include/linux/key.h b/include/linux/key.h
index 4cd22ed..cef3b31 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -303,7 +303,9 @@ static inline bool key_is_instantiated(const struct key *key)
rwsem_is_locked(&((struct key *)(KEY))->sem)))
#define rcu_assign_keypointer(KEY, PAYLOAD) \
- (rcu_assign_pointer((KEY)->payload.rcudata, PAYLOAD))
+do { \
+ rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \
+} while (0)
#ifdef CONFIG_SYSCTL
extern ctl_table key_sysctls[];
include/linux/rcupdate.h
View filediff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 9cac722..115ead2 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -147,6 +147,7 @@ extern void synchronize_sched(void);
extern void __rcu_read_lock(void);
extern void __rcu_read_unlock(void);
+extern void rcu_read_unlock_special(struct task_struct *t);
void synchronize_rcu(void);
/*
@@ -255,6 +256,10 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head)
}
#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
+#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP)
+extern int rcu_is_cpu_idle(void);
+#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP) */
+
#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU)
bool rcu_lockdep_current_cpu_online(void);
#else /* #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
@@ -266,15 +271,6 @@ static inline bool rcu_lockdep_current_cpu_online(void)
#ifdef CONFIG_DEBUG_LOCK_ALLOC
-#ifdef CONFIG_PROVE_RCU
-extern int rcu_is_cpu_idle(void);
-#else /* !CONFIG_PROVE_RCU */
-static inline int rcu_is_cpu_idle(void)
-{
- return 0;
-}
-#endif /* else !CONFIG_PROVE_RCU */
-
static inline void rcu_lock_acquire(struct lockdep_map *map)
{
lock_acquire(map, 0, 0, 2, 1, NULL, _THIS_IP_);
@@ -431,8 +427,7 @@ extern int rcu_my_thread_group_empty(void);
static inline void rcu_preempt_sleep_check(void)
{
rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
- "Illegal context switch in RCU read-side "
- "critical section");
+ "Illegal context switch in RCU read-side critical section");
}
#else /* #ifdef CONFIG_PROVE_RCU */
static inline void rcu_preempt_sleep_check(void)
@@ -513,10 +508,10 @@ static inline void rcu_preempt_sleep_check(void)
(_________p1); \
})
#define __rcu_assign_pointer(p, v, space) \
- ({ \
+ do { \
smp_wmb(); \
(p) = (typeof(*v) __force space *)(v); \
- })
+ } while (0)
/**
@@ -851,7 +846,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
*
* Assigns the specified value to the specified RCU-protected
* pointer, ensuring that any concurrent RCU readers will see
- * any prior initialization. Returns the value assigned.
+ * any prior initialization.
*
* Inserts memory barriers on architectures that require them
* (which is most of them), and also prevents the compiler from
@@ -903,25 +898,17 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
* the reader-accessible portions of the linked structure.
*/
#define RCU_INIT_POINTER(p, v) \
- p = (typeof(*v) __force __rcu *)(v)
-
-static __always_inline bool __is_kfree_rcu_offset(unsigned long offset)
-{
- return offset < 4096;
-}
-
-static __always_inline
-void __kfree_rcu(struct rcu_head *head, unsigned long offset)
-{
- typedef void (*rcu_callback)(struct rcu_head *);
-
- BUILD_BUG_ON(!__builtin_constant_p(offset));
-
- /* See the kfree_rcu() header comment. */
- BUILD_BUG_ON(!__is_kfree_rcu_offset(offset));
+ do { \
+ p = (typeof(*v) __force __rcu *)(v); \
+ } while (0)
- kfree_call_rcu(head, (rcu_callback)offset);
-}
+/**
+ * RCU_POINTER_INITIALIZER() - statically initialize an RCU protected pointer
+ *
+ * GCC-style initialization for an RCU-protected pointer in a structure field.
+ */
+#define RCU_POINTER_INITIALIZER(p, v) \
+ .p = (typeof(*v) __force __rcu *)(v)
/*
* Does the specified offset indicate that the corresponding rcu_head
@@ -935,7 +922,7 @@ void __kfree_rcu(struct rcu_head *head, unsigned long offset)
#define __kfree_rcu(head, offset) \
do { \
BUILD_BUG_ON(!__is_kfree_rcu_offset(offset)); \
- call_rcu(head, (void (*)(struct rcu_head *))(unsigned long)(offset)); \
+ kfree_call_rcu(head, (void (*)(struct rcu_head *))(unsigned long)(offset)); \
} while (0)
/**
include/trace/events/rcu.h
View filediff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index d274734..5bde94d 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -541,6 +541,50 @@ TRACE_EVENT(rcu_torture_read,
__entry->rcutorturename, __entry->rhp)
);
+/*
+ * Tracepoint for _rcu_barrier() execution. The string "s" describes
+ * the _rcu_barrier phase:
+ * "Begin": rcu_barrier_callback() started.
+ * "Check": rcu_barrier_callback() checking for piggybacking.
+ * "EarlyExit": rcu_barrier_callback() piggybacked, thus early exit.
+ * "Inc1": rcu_barrier_callback() piggyback check counter incremented.
+ * "Offline": rcu_barrier_callback() found offline CPU
+ * "OnlineQ": rcu_barrier_callback() found online CPU with callbacks.
+ * "OnlineNQ": rcu_barrier_callback() found online CPU, no callbacks.
+ * "IRQ": An rcu_barrier_callback() callback posted on remote CPU.
+ * "CB": An rcu_barrier_callback() invoked a callback, not the last.
+ * "LastCB": An rcu_barrier_callback() invoked the last callback.
+ * "Inc2": rcu_barrier_callback() piggyback check counter incremented.
+ * The "cpu" argument is the CPU or -1 if meaningless, the "cnt" argument
+ * is the count of remaining callbacks, and "done" is the piggybacking count.
+ */
+TRACE_EVENT(rcu_barrier,
+
+ TP_PROTO(char *rcuname, char *s, int cpu, int cnt, unsigned long done),
+
+ TP_ARGS(rcuname, s, cpu, cnt, done),
+
+ TP_STRUCT__entry(
+ __field(char *, rcuname)
+ __field(char *, s)
+ __field(int, cpu)
+ __field(int, cnt)
+ __field(unsigned long, done)
+ ),
+
+ TP_fast_assign(
+ __entry->rcuname = rcuname;
+ __entry->s = s;
+ __entry->cpu = cpu;
+ __entry->cnt = cnt;
+ __entry->done = done;
+ ),
+
+ TP_printk("%s %s cpu %d remaining %d # %lu",
+ __entry->rcuname, __entry->s, __entry->cpu, __entry->cnt,
+ __entry->done)
+);
+
#else /* #ifdef CONFIG_RCU_TRACE */
#define trace_rcu_grace_period(rcuname, gpnum, gpevent) do { } while (0)
@@ -564,6 +608,7 @@ TRACE_EVENT(rcu_torture_read,
#define trace_rcu_batch_end(rcuname, callbacks_invoked, cb, nr, iit, risk) \
do { } while (0)
#define trace_rcu_torture_read(rcutorturename, rhp) do { } while (0)
+#define trace_rcu_barrier(name, s, cpu, cnt, done) do { } while (0)
#endif /* #else #ifdef CONFIG_RCU_TRACE */
kernel/rcupdate.c
View filediff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 95cba41..4e6a61b 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -54,6 +54,50 @@
#ifdef CONFIG_PREEMPT_RCU
/*
+ * Preemptible RCU implementation for rcu_read_lock().
+ * Just increment ->rcu_read_lock_nesting, shared state will be updated
+ * if we block.
+ */
+void __rcu_read_lock(void)
+{
+ current->rcu_read_lock_nesting++;
+ barrier(); /* critical section after entry code. */
+}
+EXPORT_SYMBOL_GPL(__rcu_read_lock);
+
+/*
+ * Preemptible RCU implementation for rcu_read_unlock().
+ * Decrement ->rcu_read_lock_nesting. If the result is zero (outermost
+ * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
+ * invoke rcu_read_unlock_special() to clean up after a context switch
+ * in an RCU read-side critical section and other special cases.
+ */
+void __rcu_read_unlock(void)
+{
+ struct task_struct *t = current;
+
+ if (t->rcu_read_lock_nesting != 1) {
+ --t->rcu_read_lock_nesting;
+ } else {
+ barrier(); /* critical section before exit code. */
+ t->rcu_read_lock_nesting = INT_MIN;
+ barrier(); /* assign before ->rcu_read_unlock_special load */
+ if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
+ rcu_read_unlock_special(t);
+ barrier(); /* ->rcu_read_unlock_special load before assign */
+ t->rcu_read_lock_nesting = 0;
+ }
+#ifdef CONFIG_PROVE_LOCKING
+ {
+ int rrln = ACCESS_ONCE(t->rcu_read_lock_nesting);
+
+ WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2);
+ }
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+}
+EXPORT_SYMBOL_GPL(__rcu_read_unlock);
+
+/*
* Check for a task exiting while in a preemptible-RCU read-side
* critical section, clean up if so. No need to issue warnings,
* as debug_check_no_locks_held() already does this if lockdep
kernel/rcutiny.c
View filediff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 37a5444..547b1fe 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -172,7 +172,7 @@ void rcu_irq_enter(void)
local_irq_restore(flags);
}
-#ifdef CONFIG_PROVE_RCU
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
/*
* Test whether RCU thinks that the current CPU is idle.
@@ -183,7 +183,7 @@ int rcu_is_cpu_idle(void)
}
EXPORT_SYMBOL(rcu_is_cpu_idle);
-#endif /* #ifdef CONFIG_PROVE_RCU */
+#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
/*
* Test whether the current CPU was interrupted from idle. Nested
kernel/rcutiny_plugin.h
View filediff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index fc31a2d..918fd1e 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -132,7 +132,6 @@ static struct rcu_preempt_ctrlblk rcu_preempt_ctrlblk = {
RCU_TRACE(.rcb.name = "rcu_preempt")
};
-static void rcu_read_unlock_special(struct task_struct *t);
static int rcu_preempted_readers_exp(void);
static void rcu_report_exp_done(void);
@@ -351,8 +350,9 @@ static int rcu_initiate_boost(void)
rcu_preempt_ctrlblk.boost_tasks =
rcu_preempt_ctrlblk.gp_tasks;
invoke_rcu_callbacks();
- } else
+ } else {
RCU_TRACE(rcu_initiate_boost_trace());
+ }
return 1;
}
@@ -527,23 +527,11 @@ void rcu_preempt_note_context_switch(void)
}
/*
- * Tiny-preemptible RCU implementation for rcu_read_lock().
- * Just increment ->rcu_read_lock_nesting, shared state will be updated
- * if we block.
- */
-void __rcu_read_lock(void)
-{
- current->rcu_read_lock_nesting++;
- barrier(); /* needed if we ever invoke rcu_read_lock in rcutiny.c */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_lock);
-
-/*
* Handle special cases during rcu_read_unlock(), such as needing to
* notify RCU core processing or task having blocked during the RCU
* read-side critical section.
*/
-static noinline void rcu_read_unlock_special(struct task_struct *t)
+void rcu_read_unlock_special(struct task_struct *t)
{
int empty;
int empty_exp;
@@ -627,38 +615,6 @@ static noinline void rcu_read_unlock_special(struct task_struct *t)
}
/*
- * Tiny-preemptible RCU implementation for rcu_read_unlock().
- * Decrement ->rcu_read_lock_nesting. If the result is zero (outermost
- * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
- * invoke rcu_read_unlock_special() to clean up after a context switch
- * in an RCU read-side critical section and other special cases.
- */
-void __rcu_read_unlock(void)
-{
- struct task_struct *t = current;
-
- barrier(); /* needed if we ever invoke rcu_read_unlock in rcutiny.c */
- if (t->rcu_read_lock_nesting != 1)
- --t->rcu_read_lock_nesting;
- else {
- t->rcu_read_lock_nesting = INT_MIN;
- barrier(); /* assign before ->rcu_read_unlock_special load */
- if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
- rcu_read_unlock_special(t);
- barrier(); /* ->rcu_read_unlock_special load before assign */
- t->rcu_read_lock_nesting = 0;
- }
-#ifdef CONFIG_PROVE_LOCKING
- {
- int rrln = ACCESS_ONCE(t->rcu_read_lock_nesting);
-
- WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2);
- }
-#endif /* #ifdef CONFIG_PROVE_LOCKING */
-}
-EXPORT_SYMBOL_GPL(__rcu_read_unlock);
-
-/*
* Check for a quiescent state from the current CPU. When a task blocks,
* the task is recorded in the rcu_preempt_ctrlblk structure, which is
* checked elsewhere. This is called from the scheduling-clock interrupt.
@@ -823,9 +779,9 @@ void synchronize_rcu_expedited(void)
rpcp->exp_tasks = NULL;
/* Wait for tail of ->blkd_tasks list to drain. */
- if (!rcu_preempted_readers_exp())
+ if (!rcu_preempted_readers_exp()) {
local_irq_restore(flags);
- else {
+ } else {
rcu_initiate_boost();
local_irq_restore(flags);
wait_event(sync_rcu_preempt_exp_wq,
@@ -846,8 +802,6 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
*/
int rcu_preempt_needs_cpu(void)
{
- if (!rcu_preempt_running_reader())
- rcu_preempt_cpu_qs();
return rcu_preempt_ctrlblk.rcb.rcucblist != NULL;
}
kernel/rcutorture.c
View filediff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index e66b34a..25b1503 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -49,8 +49,7 @@
#include <asm/byteorder.h>
MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Paul E. McKenney <[email protected]> and "
- "Josh Triplett <[email protected]>");
+MODULE_AUTHOR("Paul E. McKenney <[email protected]> and Josh Triplett <[email protected]>");
static int nreaders = -1; /* # reader threads, defaults to 2*ncpus */
static int nfakewriters = 4; /* # fake writer threads */
@@ -206,6 +205,7 @@ static unsigned long boost_starttime; /* jiffies of next boost test start. */
DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
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kernel/rcutree.c
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kernel/rcutree.h
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kernel/rcutree_plugin.h
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kernel/rcutree_trace.c
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kernel/time/tick-sched.c
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lib/list_debug.c
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