From 309ba859b95085f61f4f2a154df6be9cb9713a12 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Wed, 11 Jul 2018 14:36:49 -0700 Subject: [PATCH] rcu: Eliminate synchronize_rcu_mult() Now that synchronize_rcu() waits for both RCU read-side critical sections and preempt-disabled regions of code, the sole caller of synchronize_rcu_mult() can be replaced by synchronize_rcu(). This patch makes this change and removes synchronize_rcu_mult(). Note that _wait_rcu_gp() still supports synchronize_rcu_mult(), and thus might be simplified in the future to take only take a single call_rcu() function rather than the current list of them. Signed-off-by: Paul E. McKenney --- include/linux/rcupdate_wait.h | 17 ----------------- kernel/rcu/update.c | 6 ++---- kernel/sched/core.c | 2 +- 3 files changed, 3 insertions(+), 22 deletions(-) diff --git a/include/linux/rcupdate_wait.h b/include/linux/rcupdate_wait.h index 8a16c3eb3dd0..c0578ba23c1a 100644 --- a/include/linux/rcupdate_wait.h +++ b/include/linux/rcupdate_wait.h @@ -31,21 +31,4 @@ do { \ #define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__) -/** - * synchronize_rcu_mult - Wait concurrently for multiple grace periods - * @...: List of call_rcu() functions for different grace periods to wait on - * - * This macro waits concurrently for multiple types of RCU grace periods. - * For example, synchronize_rcu_mult(call_rcu, call_rcu_tasks) would wait - * on concurrent RCU and RCU-tasks grace periods. Waiting on a give SRCU - * domain requires you to write a wrapper function for that SRCU domain's - * call_srcu() function, supplying the corresponding srcu_struct. - * - * If Tiny RCU, tell _wait_rcu_gp() does not bother waiting for RCU, - * given that anywhere synchronize_rcu_mult() can be called is automatically - * a grace period. - */ -#define synchronize_rcu_mult(...) \ - _wait_rcu_gp(IS_ENABLED(CONFIG_TINY_RCU), __VA_ARGS__) - #endif /* _LINUX_SCHED_RCUPDATE_WAIT_H */ diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index f203b94f6b5b..c729ca5e6ee2 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -335,8 +335,7 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, /* Initialize and register callbacks for each crcu_array element. */ for (i = 0; i < n; i++) { if (checktiny && - (crcu_array[i] == call_rcu || - crcu_array[i] == call_rcu_bh)) { + (crcu_array[i] == call_rcu)) { might_sleep(); continue; } @@ -352,8 +351,7 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array, /* Wait for all callbacks to be invoked. */ for (i = 0; i < n; i++) { if (checktiny && - (crcu_array[i] == call_rcu || - crcu_array[i] == call_rcu_bh)) + (crcu_array[i] == call_rcu)) continue; for (j = 0; j < i; j++) if (crcu_array[j] == crcu_array[i]) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f12225f26b70..ea12ebc57840 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5788,7 +5788,7 @@ int sched_cpu_deactivate(unsigned int cpu) * * Do sync before park smpboot threads to take care the rcu boost case. */ - synchronize_rcu_mult(call_rcu, call_rcu_sched); + synchronize_rcu(); if (!sched_smp_initialized) return 0; -- 2.45.2