From: Frederic Weisbecker <frederic@kernel.org>
To: "Paul E . McKenney" <paulmck@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <frederic@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Phil Auld <pauld@redhat.com>, Alex Belits <abelits@marvell.com>,
Nicolas Saenz Julienne <nsaenz@kernel.org>,
Marco Elver <elver@google.com>,
Xiongfeng Wang <wangxiongfeng2@huawei.com>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Thomas Gleixner <tglx@linutronix.de>,
Nicolas Saenz Julienne <nsaenzju@redhat.com>,
Max Filippov <jcmvbkbc@gmail.com>, Yu Liao <liaoyu15@huawei.com>,
Boqun Feng <boqun.feng@gmail.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
kernel test robot <lkp@intel.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Uladzislau Rezki <uladzislau.rezki@sony.com>,
Joel Fernandes <joel@joelfernandes.org>
Subject: [PATCH 11/20] rcu/context-tracking: Remove rcu_irq_enter/exit()
Date: Tue, 28 Jun 2022 15:16:10 +0200 [thread overview]
Message-ID: <20220628131619.2109651-12-frederic@kernel.org> (raw)
In-Reply-To: <20220628131619.2109651-1-frederic@kernel.org>
Now rcu_irq_enter/exit() is an unnecessary middle call between
ct_irq_enter/exit() and nmi_irq_enter/exit(). Take this opportunity
to remove the former functions and move the comments above them to the
new entrypoints.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com>
Cc: Uladzislau Rezki <uladzislau.rezki@sony.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Cc: Yu Liao <liaoyu15@huawei.com>
Cc: Phil Auld <pauld@redhat.com>
Cc: Paul Gortmaker<paul.gortmaker@windriver.com>
Cc: Alex Belits <abelits@marvell.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Reviewed-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Tested-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
---
include/linux/rcutiny.h | 4 --
include/linux/rcutree.h | 4 --
kernel/context_tracking.c | 71 +++++++++++++++++++++++++++++++--
kernel/rcu/tree.c | 83 ---------------------------------------
4 files changed, 67 insertions(+), 95 deletions(-)
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 5fed476f977f..591119413cf1 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -78,10 +78,6 @@ static inline void rcu_cpu_stall_reset(void) { }
static inline int rcu_jiffies_till_stall_check(void) { return 21 * HZ; }
static inline void rcu_idle_enter(void) { }
static inline void rcu_idle_exit(void) { }
-static inline void rcu_irq_enter(void) { }
-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_check_preempt(void) { }
#define rcu_is_idle_cpu(cpu) \
(is_idle_task(current) && !in_nmi() && !in_hardirq() && !in_serving_softirq())
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 9c6cfb742504..4522b6a7cc42 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -47,10 +47,6 @@ void cond_synchronize_rcu(unsigned long oldstate);
void rcu_idle_enter(void);
void rcu_idle_exit(void);
-void rcu_irq_enter(void);
-void rcu_irq_exit(void);
-void rcu_irq_enter_irqson(void);
-void rcu_irq_exit_irqson(void);
bool rcu_is_idle_cpu(int cpu);
#ifdef CONFIG_PROVE_RCU
diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index b8a731f20778..c0d86dac98f1 100644
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -36,24 +36,87 @@ void ct_idle_exit(void)
}
EXPORT_SYMBOL_GPL(ct_idle_exit);
+/**
+ * ct_irq_enter - inform RCU that current CPU is entering irq away from idle
+ *
+ * Enter an interrupt handler, which might possibly result in exiting
+ * idle mode, in other words, entering the mode in which read-side critical
+ * sections can occur. The caller must have disabled interrupts.
+ *
+ * Note that the Linux kernel is fully capable of entering an interrupt
+ * handler that it never exits, for example when doing upcalls to user mode!
+ * This code assumes that the idle loop never does upcalls to user mode.
+ * If your architecture's idle loop does do upcalls to user mode (or does
+ * anything else that results in unbalanced calls to the irq_enter() and
+ * irq_exit() functions), RCU will give you what you deserve, good and hard.
+ * But very infrequently and irreproducibly.
+ *
+ * Use things like work queues to work around this limitation.
+ *
+ * You have been warned.
+ *
+ * If you add or remove a call to ct_irq_enter(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
noinstr void ct_irq_enter(void)
{
- rcu_irq_enter();
+ lockdep_assert_irqs_disabled();
+ ct_nmi_enter();
}
+/**
+ * ct_irq_exit - inform RCU that current CPU is exiting irq towards idle
+ *
+ * Exit from an interrupt handler, which might possibly result in entering
+ * idle mode, in other words, leaving the mode in which read-side critical
+ * sections can occur. The caller must have disabled interrupts.
+ *
+ * This code assumes that the idle loop never does anything that might
+ * result in unbalanced calls to irq_enter() and irq_exit(). If your
+ * architecture's idle loop violates this assumption, RCU will give you what
+ * you deserve, good and hard. But very infrequently and irreproducibly.
+ *
+ * Use things like work queues to work around this limitation.
+ *
+ * You have been warned.
+ *
+ * If you add or remove a call to ct_irq_exit(), be sure to test with
+ * CONFIG_RCU_EQS_DEBUG=y.
+ */
noinstr void ct_irq_exit(void)
{
- rcu_irq_exit();
+ lockdep_assert_irqs_disabled();
+ ct_nmi_exit();
}
+/*
+ * Wrapper for ct_irq_enter() where interrupts are enabled.
+ *
+ * If you add or remove a call to ct_irq_enter_irqson(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
void ct_irq_enter_irqson(void)
{
- rcu_irq_enter_irqson();
+ unsigned long flags;
+
+ local_irq_save(flags);
+ ct_irq_enter();
+ local_irq_restore(flags);
}
+/*
+ * Wrapper for ct_irq_exit() where interrupts are enabled.
+ *
+ * If you add or remove a call to ct_irq_exit_irqson(), be sure to test
+ * with CONFIG_RCU_EQS_DEBUG=y.
+ */
void ct_irq_exit_irqson(void)
{
- rcu_irq_exit_irqson();
+ unsigned long flags;
+
+ local_irq_save(flags);
+ ct_irq_exit();
+ local_irq_restore(flags);
}
noinstr void ct_nmi_enter(void)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 051fed0844b6..75b433dba427 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -789,31 +789,6 @@ noinstr void rcu_nmi_exit(void)
rcu_dynticks_task_enter();
}
-/**
- * rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle
- *
- * Exit from an interrupt handler, which might possibly result in entering
- * idle mode, in other words, leaving the mode in which read-side critical
- * sections can occur. The caller must have disabled interrupts.
- *
- * This code assumes that the idle loop never does anything that might
- * result in unbalanced calls to irq_enter() and irq_exit(). If your
- * architecture's idle loop violates this assumption, RCU will give you what
- * you deserve, good and hard. But very infrequently and irreproducibly.
- *
- * Use things like work queues to work around this limitation.
- *
- * You have been warned.
- *
- * If you add or remove a call to rcu_irq_exit(), be sure to test with
- * CONFIG_RCU_EQS_DEBUG=y.
- */
-void noinstr rcu_irq_exit(void)
-{
- lockdep_assert_irqs_disabled();
- rcu_nmi_exit();
-}
-
#ifdef CONFIG_PROVE_RCU
/**
* rcu_irq_exit_check_preempt - Validate that scheduling is possible
@@ -832,21 +807,6 @@ void rcu_irq_exit_check_preempt(void)
}
#endif /* #ifdef CONFIG_PROVE_RCU */
-/*
- * Wrapper for rcu_irq_exit() where interrupts are enabled.
- *
- * If you add or remove a call to rcu_irq_exit_irqson(), be sure to test
- * with CONFIG_RCU_EQS_DEBUG=y.
- */
-void rcu_irq_exit_irqson(void)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- rcu_irq_exit();
- local_irq_restore(flags);
-}
-
/*
* Exit an RCU extended quiescent state, which can be either the
* idle loop or adaptive-tickless usermode execution.
@@ -1041,49 +1001,6 @@ noinstr void rcu_nmi_enter(void)
barrier();
}
-/**
- * rcu_irq_enter - inform RCU that current CPU is entering irq away from idle
- *
- * Enter an interrupt handler, which might possibly result in exiting
- * idle mode, in other words, entering the mode in which read-side critical
- * sections can occur. The caller must have disabled interrupts.
- *
- * Note that the Linux kernel is fully capable of entering an interrupt
- * handler that it never exits, for example when doing upcalls to user mode!
- * This code assumes that the idle loop never does upcalls to user mode.
- * If your architecture's idle loop does do upcalls to user mode (or does
- * anything else that results in unbalanced calls to the irq_enter() and
- * irq_exit() functions), RCU will give you what you deserve, good and hard.
- * But very infrequently and irreproducibly.
- *
- * Use things like work queues to work around this limitation.
- *
- * You have been warned.
- *
- * If you add or remove a call to rcu_irq_enter(), be sure to test with
- * CONFIG_RCU_EQS_DEBUG=y.
- */
-noinstr void rcu_irq_enter(void)
-{
- lockdep_assert_irqs_disabled();
- rcu_nmi_enter();
-}
-
-/*
- * Wrapper for rcu_irq_enter() where interrupts are enabled.
- *
- * If you add or remove a call to rcu_irq_enter_irqson(), be sure to test
- * with CONFIG_RCU_EQS_DEBUG=y.
- */
-void rcu_irq_enter_irqson(void)
-{
- unsigned long flags;
-
- local_irq_save(flags);
- rcu_irq_enter();
- local_irq_restore(flags);
-}
-
/*
* Check to see if any future non-offloaded RCU-related work will need
* to be done by the current CPU, even if none need be done immediately,
--
2.25.1
next prev parent reply other threads:[~2022-06-28 13:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-28 13:15 [PATCH 00/20] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking v5 Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 01/20] context_tracking: Remove unused context_tracking_in_user() Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 02/20] context_tracking: Add a note about noinstr VS unsafe context tracking functions Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 03/20] context_tracking: Rename __context_tracking_enter/exit() to __ct_user_enter/exit() Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 04/20] context_tracking: Rename context_tracking_user_enter/exit() to user_enter/exit_callable() Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 05/20] context_tracking: Rename context_tracking_enter/exit() to ct_user_enter/exit() Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 06/20] context_tracking: Rename context_tracking_cpu_set() to ct_cpu_track_user() Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 07/20] context_tracking: Split user tracking Kconfig Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 08/20] context_tracking: Take idle eqs entrypoints over RCU Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 09/20] context_tracking: Take IRQ " Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 10/20] context_tracking: Take NMI " Frederic Weisbecker
2022-06-28 13:16 ` Frederic Weisbecker [this message]
2022-06-28 13:16 ` [PATCH 12/20] rcu/context_tracking: Move dynticks counter to context tracking Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 13/20] rcu/context_tracking: Move dynticks_nesting " Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 14/20] rcu/context_tracking: Move dynticks_nmi_nesting " Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 15/20] rcu/context-tracking: Move deferred nocb resched " Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 16/20] rcu/context-tracking: Move RCU-dynticks internal functions to context_tracking Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 17/20] rcu/context-tracking: Remove unused and/or unecessary middle functions Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 18/20] context_tracking: Convert state to atomic_t Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 19/20] MAINTAINERS: Add Paul as context tracking maintainer Frederic Weisbecker
2022-06-28 13:16 ` [PATCH 20/20] context_tracking: Use arch_atomic_read() in __ct_state for KASAN Frederic Weisbecker
2022-06-30 0:10 ` [PATCH 00/20] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking v5 Paul E. McKenney
2022-10-11 11:37 ` Xiongfeng Wang
2022-10-11 19:12 ` Frederic Weisbecker
2022-10-12 1:08 ` Xiongfeng Wang
-- strict thread matches above, loose matches on Subject: below --
2022-06-08 14:40 [PATCH 00/20] rcu/context-tracking: Merge RCU eqs-dynticks counter to context tracking v4 Frederic Weisbecker
2022-06-08 14:40 ` [PATCH 11/20] rcu/context-tracking: Remove rcu_irq_enter/exit() Frederic Weisbecker
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