diff options
| author | Ingo Molnar <mingo@elte.hu> | 2006-01-08 10:01:37 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-09 05:13:40 +0100 |
| commit | e56d090310d7625ecb43a1eeebd479f04affb48b (patch) | |
| tree | 2f479215dff4a2d8f3a9ed85200a5bc4f51534be /include | |
| parent | [PATCH] Make RCU task_struct safe for oprofile (diff) | |
| download | linux-e56d090310d7625ecb43a1eeebd479f04affb48b.tar.xz linux-e56d090310d7625ecb43a1eeebd479f04affb48b.zip | |
[PATCH] RCU signal handling
RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked
instead of tasklist_lock read-locked. This is a scalability improvement on
SMP and a preemption-latency improvement under PREEMPT_RCU.
Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Acked-by: William Irwin <wli@holomorphy.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index a74662077d60..a6af77e9b4cf 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -34,6 +34,7 @@ #include <linux/percpu.h> #include <linux/topology.h> #include <linux/seccomp.h> +#include <linux/rcupdate.h> #include <linux/auxvec.h> /* For AT_VECTOR_SIZE */ @@ -350,8 +351,16 @@ struct sighand_struct { atomic_t count; struct k_sigaction action[_NSIG]; spinlock_t siglock; + struct rcu_head rcu; }; +extern void sighand_free_cb(struct rcu_head *rhp); + +static inline void sighand_free(struct sighand_struct *sp) +{ + call_rcu(&sp->rcu, sighand_free_cb); +} + /* * NOTE! "signal_struct" does not have it's own * locking, because a shared signal_struct always @@ -844,6 +853,7 @@ struct task_struct { int cpuset_mems_generation; #endif atomic_t fs_excl; /* holding fs exclusive resources */ + struct rcu_head rcu; }; static inline pid_t process_group(struct task_struct *tsk) @@ -867,8 +877,26 @@ static inline int pid_alive(struct task_struct *p) extern void free_task(struct task_struct *tsk); extern void __put_task_struct(struct task_struct *tsk); #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0) -#define put_task_struct(tsk) \ -do { if (atomic_dec_and_test(&(tsk)->usage)) __put_task_struct(tsk); } while(0) + +static inline int get_task_struct_rcu(struct task_struct *t) +{ + int oldusage; + + do { + oldusage = atomic_read(&t->usage); + if (oldusage == 0) + return 0; + } while (cmpxchg(&t->usage.counter, oldusage, oldusage+1) != oldusage); + return 1; +} + +extern void __put_task_struct_cb(struct rcu_head *rhp); + +static inline void put_task_struct(struct task_struct *t) +{ + if (atomic_dec_and_test(&t->usage)) + call_rcu(&t->rcu, __put_task_struct_cb); +} /* * Per process flags |