mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-09-22 04:31:58 +08:00
rcu: Export rcu_request_urgent_qs_task()
If a CPU is executing a long series of non-sleeping system calls, RCU grace periods can be delayed for on the order of a couple hundred milliseconds. This is normally not a problem, but if each system call does a call_rcu(), those callbacks can stack up. RCU will eventually notice this callback storm, but use of rcu_request_urgent_qs_task() allows the code invoking call_rcu() to give RCU a heads up. This function is not for general use, not yet, anyway. Reported-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20230706033447.54696-11-alexei.starovoitov@gmail.com
This commit is contained in:
parent
04fabf00b4
commit
43a89baecf
@ -138,6 +138,8 @@ static inline int rcu_needs_cpu(void)
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
|
||||
|
||||
/*
|
||||
* Take advantage of the fact that there is only one CPU, which
|
||||
* allows us to ignore virtualization-based context switches.
|
||||
|
@ -21,6 +21,7 @@ void rcu_softirq_qs(void);
|
||||
void rcu_note_context_switch(bool preempt);
|
||||
int rcu_needs_cpu(void);
|
||||
void rcu_cpu_stall_reset(void);
|
||||
void rcu_request_urgent_qs_task(struct task_struct *t);
|
||||
|
||||
/*
|
||||
* Note a virtualization-based context switch. This is simply a
|
||||
|
@ -493,7 +493,6 @@ static inline void rcu_expedite_gp(void) { }
|
||||
static inline void rcu_unexpedite_gp(void) { }
|
||||
static inline void rcu_async_hurry(void) { }
|
||||
static inline void rcu_async_relax(void) { }
|
||||
static inline void rcu_request_urgent_qs_task(struct task_struct *t) { }
|
||||
#else /* #ifdef CONFIG_TINY_RCU */
|
||||
bool rcu_gp_is_normal(void); /* Internal RCU use. */
|
||||
bool rcu_gp_is_expedited(void); /* Internal RCU use. */
|
||||
@ -508,7 +507,6 @@ void show_rcu_tasks_gp_kthreads(void);
|
||||
#else /* #ifdef CONFIG_TASKS_RCU_GENERIC */
|
||||
static inline void show_rcu_tasks_gp_kthreads(void) {}
|
||||
#endif /* #else #ifdef CONFIG_TASKS_RCU_GENERIC */
|
||||
void rcu_request_urgent_qs_task(struct task_struct *t);
|
||||
#endif /* #else #ifdef CONFIG_TINY_RCU */
|
||||
|
||||
#define RCU_SCHEDULER_INACTIVE 0
|
||||
|
Loading…
Reference in New Issue
Block a user