* [PATCH tip/core/rcu 1/5] rcu-tasks: Convert sleeps to idle priority
2020-06-23 0:24 [PATCH tip/core/rcu 0/5] RCU tasks updates for v5.9 Paul E. McKenney
@ 2020-06-23 0:24 ` paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 2/5] rcu-tasks: Make rcu_tasks_postscan() be static paulmck
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: paulmck @ 2020-06-23 0:24 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, dipankar, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Paul E. McKenney
From: "Paul E. McKenney" <paulmck@kernel.org>
This commit converts the long-standing schedule_timeout_interruptible()
and schedule_timeout_uninterruptible() calls used by the various Tasks
RCU's grace-period kthreads to schedule_timeout_idle(). This conversion
avoids polluting the load-average with Tasks-RCU-related sleeping.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tasks.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index ce23f6c..91fee81 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -205,7 +205,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
if (!rtp->cbs_head) {
WARN_ON(signal_pending(current));
set_tasks_gp_state(rtp, RTGS_WAIT_WAIT_CBS);
- schedule_timeout_interruptible(HZ/10);
+ schedule_timeout_idle(HZ/10);
}
continue;
}
@@ -227,7 +227,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
cond_resched();
}
/* Paranoid sleep to keep this from entering a tight loop */
- schedule_timeout_uninterruptible(HZ/10);
+ schedule_timeout_idle(HZ/10);
set_tasks_gp_state(rtp, RTGS_WAIT_CBS);
}
@@ -336,7 +336,7 @@ static void rcu_tasks_wait_gp(struct rcu_tasks *rtp)
/* Slowly back off waiting for holdouts */
set_tasks_gp_state(rtp, RTGS_WAIT_SCAN_HOLDOUTS);
- schedule_timeout_interruptible(HZ/fract);
+ schedule_timeout_idle(HZ/fract);
if (fract > 1)
fract--;
--
2.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH tip/core/rcu 2/5] rcu-tasks: Make rcu_tasks_postscan() be static
2020-06-23 0:24 [PATCH tip/core/rcu 0/5] RCU tasks updates for v5.9 Paul E. McKenney
2020-06-23 0:24 ` [PATCH tip/core/rcu 1/5] rcu-tasks: Convert sleeps to idle priority paulmck
@ 2020-06-23 0:24 ` paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 3/5] rcu-tasks: Add #include of rcupdate_trace.h to update.c paulmck
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: paulmck @ 2020-06-23 0:24 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, dipankar, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Paul E. McKenney
From: "Paul E. McKenney" <paulmck@kernel.org>
The rcu_tasks_postscan() function is not used outside of RCU's tasks.h
file, so this commit makes it be static.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tasks.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 91fee81..da200e5 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -402,7 +402,7 @@ static void rcu_tasks_pertask(struct task_struct *t, struct list_head *hop)
}
/* Processing between scanning taskslist and draining the holdout list. */
-void rcu_tasks_postscan(struct list_head *hop)
+static void rcu_tasks_postscan(struct list_head *hop)
{
/*
* Wait for tasks that are in the process of exiting. This
--
2.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH tip/core/rcu 3/5] rcu-tasks: Add #include of rcupdate_trace.h to update.c
2020-06-23 0:24 [PATCH tip/core/rcu 0/5] RCU tasks updates for v5.9 Paul E. McKenney
2020-06-23 0:24 ` [PATCH tip/core/rcu 1/5] rcu-tasks: Convert sleeps to idle priority paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 2/5] rcu-tasks: Make rcu_tasks_postscan() be static paulmck
@ 2020-06-23 0:24 ` paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 4/5] rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads() paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 5/5] rcu-tasks: Fix code-style issues paulmck
4 siblings, 0 replies; 6+ messages in thread
From: paulmck @ 2020-06-23 0:24 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, dipankar, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Paul E. McKenney
From: "Paul E. McKenney" <paulmck@kernel.org>
Although this is in some strict sense unnecessary, it is good to allow
the compiler to compare the function declaration with its definition.
This commit therefore adds a #include of linux/rcupdate_trace.h to
kernel/rcu/update.c.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/update.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 84843ad..c0fea80 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -42,6 +42,7 @@
#include <linux/kprobes.h>
#include <linux/slab.h>
#include <linux/irq_work.h>
+#include <linux/rcupdate_trace.h>
#define CREATE_TRACE_POINTS
--
2.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH tip/core/rcu 4/5] rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads()
2020-06-23 0:24 [PATCH tip/core/rcu 0/5] RCU tasks updates for v5.9 Paul E. McKenney
` (2 preceding siblings ...)
2020-06-23 0:24 ` [PATCH tip/core/rcu 3/5] rcu-tasks: Add #include of rcupdate_trace.h to update.c paulmck
@ 2020-06-23 0:24 ` paulmck
2020-06-23 0:24 ` [PATCH tip/core/rcu 5/5] rcu-tasks: Fix code-style issues paulmck
4 siblings, 0 replies; 6+ messages in thread
From: paulmck @ 2020-06-23 0:24 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, dipankar, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Paul E. McKenney
From: "Paul E. McKenney" <paulmck@kernel.org>
The show_rcu_tasks_gp_kthreads() function is not invoked by Tiny RCU,
but is nevertheless defined in Tiny RCU builds that enable Tasks Trace
RCU. This commit therefore conditionally compiles this function so
that it is defined only in builds that actually use it.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tasks.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index da200e5..d5c003c 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -103,6 +103,7 @@ module_param(rcu_task_stall_timeout, int, 0644);
#define RTGS_WAIT_READERS 9
#define RTGS_INVOKE_CBS 10
#define RTGS_WAIT_CBS 11
+#ifndef CONFIG_TINY_RCU
static const char * const rcu_tasks_gp_state_names[] = {
"RTGS_INIT",
"RTGS_WAIT_WAIT_CBS",
@@ -117,6 +118,7 @@ static const char * const rcu_tasks_gp_state_names[] = {
"RTGS_INVOKE_CBS",
"RTGS_WAIT_CBS",
};
+#endif /* #ifndef CONFIG_TINY_RCU */
////////////////////////////////////////////////////////////////////////
//
@@ -129,6 +131,7 @@ static void set_tasks_gp_state(struct rcu_tasks *rtp, int newstate)
rtp->gp_jiffies = jiffies;
}
+#ifndef CONFIG_TINY_RCU
/* Return state name. */
static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)
{
@@ -139,6 +142,7 @@ static const char *tasks_gp_state_getname(struct rcu_tasks *rtp)
return "???";
return rcu_tasks_gp_state_names[j];
}
+#endif /* #ifndef CONFIG_TINY_RCU */
// Enqueue a callback for the specified flavor of Tasks RCU.
static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
@@ -268,6 +272,7 @@ static void __init rcu_tasks_bootup_oddness(void)
#endif /* #ifndef CONFIG_TINY_RCU */
+#ifndef CONFIG_TINY_RCU
/* Dump out rcutorture-relevant state common to all RCU-tasks flavors. */
static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
{
@@ -281,6 +286,7 @@ static void show_rcu_tasks_generic_gp_kthread(struct rcu_tasks *rtp, char *s)
".C"[!!data_race(rtp->cbs_head)],
s);
}
+#endif /* #ifndef CONFIG_TINY_RCU */
static void exit_tasks_rcu_finish_trace(struct task_struct *t);
@@ -557,10 +563,12 @@ static int __init rcu_spawn_tasks_kthread(void)
}
core_initcall(rcu_spawn_tasks_kthread);
+#ifndef CONFIG_TINY_RCU
static void show_rcu_tasks_classic_gp_kthread(void)
{
show_rcu_tasks_generic_gp_kthread(&rcu_tasks, "");
}
+#endif /* #ifndef CONFIG_TINY_RCU */
/* Do the srcu_read_lock() for the above synchronize_srcu(). */
void exit_tasks_rcu_start(void) __acquires(&tasks_rcu_exit_srcu)
@@ -682,10 +690,12 @@ static int __init rcu_spawn_tasks_rude_kthread(void)
}
core_initcall(rcu_spawn_tasks_rude_kthread);
+#ifndef CONFIG_TINY_RCU
static void show_rcu_tasks_rude_gp_kthread(void)
{
show_rcu_tasks_generic_gp_kthread(&rcu_tasks_rude, "");
}
+#endif /* #ifndef CONFIG_TINY_RCU */
#else /* #ifdef CONFIG_TASKS_RUDE_RCU */
static void show_rcu_tasks_rude_gp_kthread(void) {}
@@ -1164,6 +1174,7 @@ static int __init rcu_spawn_tasks_trace_kthread(void)
}
core_initcall(rcu_spawn_tasks_trace_kthread);
+#ifndef CONFIG_TINY_RCU
static void show_rcu_tasks_trace_gp_kthread(void)
{
char buf[64];
@@ -1174,18 +1185,21 @@ static void show_rcu_tasks_trace_gp_kthread(void)
data_race(n_heavy_reader_attempts));
show_rcu_tasks_generic_gp_kthread(&rcu_tasks_trace, buf);
}
+#endif /* #ifndef CONFIG_TINY_RCU */
#else /* #ifdef CONFIG_TASKS_TRACE_RCU */
static void exit_tasks_rcu_finish_trace(struct task_struct *t) { }
static inline void show_rcu_tasks_trace_gp_kthread(void) {}
#endif /* #else #ifdef CONFIG_TASKS_TRACE_RCU */
+#ifndef CONFIG_TINY_RCU
void show_rcu_tasks_gp_kthreads(void)
{
show_rcu_tasks_classic_gp_kthread();
show_rcu_tasks_rude_gp_kthread();
show_rcu_tasks_trace_gp_kthread();
}
+#endif /* #ifndef CONFIG_TINY_RCU */
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
static inline void rcu_tasks_bootup_oddness(void) {}
--
2.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH tip/core/rcu 5/5] rcu-tasks: Fix code-style issues
2020-06-23 0:24 [PATCH tip/core/rcu 0/5] RCU tasks updates for v5.9 Paul E. McKenney
` (3 preceding siblings ...)
2020-06-23 0:24 ` [PATCH tip/core/rcu 4/5] rcu-tasks: Conditionally compile show_rcu_tasks_gp_kthreads() paulmck
@ 2020-06-23 0:24 ` paulmck
4 siblings, 0 replies; 6+ messages in thread
From: paulmck @ 2020-06-23 0:24 UTC (permalink / raw)
To: rcu
Cc: linux-kernel, kernel-team, mingo, jiangshanlai, dipankar, akpm,
mathieu.desnoyers, josh, tglx, peterz, rostedt, dhowells,
edumazet, fweisbec, oleg, joel, Paul E. McKenney
From: "Paul E. McKenney" <paulmck@kernel.org>
This commit declares trc_n_readers_need_end and trc_wait static and
replaced a "&" with "&&". The "&" happened to work because the values
are bool, but accidents waiting to happen and all that...
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/rcu/tasks.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index d5c003c..828f222 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -737,8 +737,8 @@ EXPORT_SYMBOL_GPL(rcu_trace_lock_map);
#ifdef CONFIG_TASKS_TRACE_RCU
-atomic_t trc_n_readers_need_end; // Number of waited-for readers.
-DECLARE_WAIT_QUEUE_HEAD(trc_wait); // List of holdout tasks.
+static atomic_t trc_n_readers_need_end; // Number of waited-for readers.
+static DECLARE_WAIT_QUEUE_HEAD(trc_wait); // List of holdout tasks.
// Record outstanding IPIs to each CPU. No point in sending two...
static DEFINE_PER_CPU(bool, trc_ipi_to_cpu);
@@ -845,7 +845,7 @@ static bool trc_inspect_reader(struct task_struct *t, void *arg)
bool ofl = cpu_is_offline(cpu);
if (task_curr(t)) {
- WARN_ON_ONCE(ofl & !is_idle_task(t));
+ WARN_ON_ONCE(ofl && !is_idle_task(t));
// If no chance of heavyweight readers, do it the hard way.
if (!ofl && !IS_ENABLED(CONFIG_TASKS_TRACE_RCU_READ_MB))
--
2.9.5
^ permalink raw reply related [flat|nested] 6+ messages in thread