From 24278d148316d2180be6df40e06db013d8b232b8 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 27 Sep 2010 17:25:23 -0700 Subject: rcu: priority boosting for TINY_PREEMPT_RCU Add priority boosting, but only for TINY_PREEMPT_RCU. This is enabled by the default-off RCU_BOOST kernel parameter. The priority to which to boost preempted RCU readers is controlled by the RCU_BOOST_PRIO kernel parameter (defaulting to real-time priority 1) and the time to wait before boosting the readers blocking a given grace period is controlled by the RCU_BOOST_DELAY kernel parameter (defaulting to 500 milliseconds). Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- include/linux/init_task.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'include/linux/init_task.h') diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 2fea6c8ef6ba..69f91aacdeee 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -81,6 +81,12 @@ extern struct group_info init_groups; */ # define CAP_INIT_BSET CAP_FULL_SET +#ifdef CONFIG_RCU_BOOST +#define INIT_TASK_RCU_BOOST() \ + .rcu_boost_mutex = NULL, +#else +#define INIT_TASK_RCU_BOOST() +#endif #ifdef CONFIG_TREE_PREEMPT_RCU #define INIT_TASK_RCU_TREE_PREEMPT() \ .rcu_blocked_node = NULL, @@ -92,7 +98,8 @@ extern struct group_info init_groups; .rcu_read_lock_nesting = 0, \ .rcu_read_unlock_special = 0, \ .rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \ - INIT_TASK_RCU_TREE_PREEMPT() + INIT_TASK_RCU_TREE_PREEMPT() \ + INIT_TASK_RCU_BOOST() #else #define INIT_TASK_RCU_PREEMPT(tsk) #endif -- cgit v1.2.3 From 806c09a7db457be3758e14b1f152761135d89af5 Mon Sep 17 00:00:00 2001 From: Dario Faggioli Date: Tue, 30 Nov 2010 19:51:33 +0100 Subject: sched: Make pushable_tasks CONFIG_SMP dependant As noted by Peter Zijlstra at https://lkml.org/lkml/2010/11/10/391 (while reviewing other stuff, though), tracking pushable tasks only makes sense on SMP systems. Signed-off-by: Dario Faggioli Acked-by: Steven Rostedt Acked-by: Gregory Haskins Signed-off-by: Peter Zijlstra LKML-Reference: <1291143093.2697.298.camel@Palantir> Signed-off-by: Ingo Molnar --- include/linux/init_task.h | 9 ++++++++- include/linux/sched.h | 2 ++ kernel/sched.c | 2 ++ 3 files changed, 12 insertions(+), 1 deletion(-) (limited to 'include/linux/init_task.h') diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 1f8c06ce0fa6..6ed8812bfe2d 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -12,6 +12,13 @@ #include #include +#ifdef CONFIG_SMP +# define INIT_PUSHABLE_TASKS(tsk) \ + .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), +#else +# define INIT_PUSHABLE_TASKS(tsk) +#endif + extern struct files_struct init_files; extern struct fs_struct init_fs; @@ -137,7 +144,7 @@ extern struct cred init_cred; .nr_cpus_allowed = NR_CPUS, \ }, \ .tasks = LIST_HEAD_INIT(tsk.tasks), \ - .pushable_tasks = PLIST_NODE_INIT(tsk.pushable_tasks, MAX_PRIO), \ + INIT_PUSHABLE_TASKS(tsk) \ .ptraced = LIST_HEAD_INIT(tsk.ptraced), \ .ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \ .real_parent = &tsk, \ diff --git a/include/linux/sched.h b/include/linux/sched.h index 9c2d46da486e..4f92a239c14d 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1240,7 +1240,9 @@ struct task_struct { #endif struct list_head tasks; +#ifdef CONFIG_SMP struct plist_node pushable_tasks; +#endif struct mm_struct *mm, *active_mm; #if defined(SPLIT_RSS_COUNTING) diff --git a/kernel/sched.c b/kernel/sched.c index b646dad4a40e..3925a1bbf5dd 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2595,7 +2595,9 @@ void sched_fork(struct task_struct *p, int clone_flags) /* Want to start with kernel preemption disabled. */ task_thread_info(p)->preempt_count = 1; #endif +#ifdef CONFIG_SMP plist_node_init(&p->pushable_tasks, MAX_PRIO); +#endif put_cpu(); } -- cgit v1.2.3