diff options
| author | Dipankar Sarma <dipankar@in.ibm.com> | 2004-08-22 22:58:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2004-08-22 22:58:16 -0700 |
| commit | f4d4d3f33efca5261c6313ead7d4b6d3a6add711 (patch) | |
| tree | dad2fdbe47a125488716594bb2edf28f87b62d67 /include | |
| parent | a879f6e985b868512fb2aecf183be6caf82b7023 (diff) | |
[PATCH] rcu: introduce call_rcu_bh()
Introduces call_rcu_bh() to be used when critical sections are mostly in
softirq context.
This patch introduces a new api - call_rcu_bh(). This is to be used for RCU
callbacks for whom the critical sections are mostly in softirq context. These
callbacks consider completion of a softirq handler to be a quiescent state.
So, in order to make reader critical sections safe in process context,
rcu_read_lock_bh() and rcu_read_unlock_bh() must be used. Use of softirq
handler completion as a quiescent state speeds up RCU grace periods and
prevents too many callbacks getting queued up in softirq-heavy workloads like
network stack.
Signed-off-by: Dipankar Sarma <dipankar@in.ibm.com>
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/rcupdate.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 8c8157be11f7..f003f8ff9789 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -105,7 +105,9 @@ struct rcu_data { }; DECLARE_PER_CPU(struct rcu_data, rcu_data); +DECLARE_PER_CPU(struct rcu_data, rcu_bh_data); extern struct rcu_ctrlblk rcu_ctrlblk; +extern struct rcu_ctrlblk rcu_bh_ctrlblk; /* * Increment the quiscent state counter. @@ -115,6 +117,11 @@ static inline void rcu_qsctr_inc(int cpu) struct rcu_data *rdp = &per_cpu(rcu_data, cpu); rdp->qsctr++; } +static inline void rcu_bh_qsctr_inc(int cpu) +{ + struct rcu_data *rdp = &per_cpu(rcu_bh_data, cpu); + rdp->qsctr++; +} static inline int __rcu_pending(struct rcu_ctrlblk *rcp, struct rcu_data *rdp) @@ -143,11 +150,14 @@ static inline int __rcu_pending(struct rcu_ctrlblk *rcp, static inline int rcu_pending(int cpu) { - return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)); + return __rcu_pending(&rcu_ctrlblk, &per_cpu(rcu_data, cpu)) || + __rcu_pending(&rcu_bh_ctrlblk, &per_cpu(rcu_bh_data, cpu)); } #define rcu_read_lock() preempt_disable() #define rcu_read_unlock() preempt_enable() +#define rcu_read_lock_bh() local_bh_disable() +#define rcu_read_unlock_bh() local_bh_enable() extern void rcu_init(void); extern void rcu_check_callbacks(int cpu, int user); @@ -156,6 +166,8 @@ extern void rcu_restart_cpu(int cpu); /* Exported interfaces */ extern void FASTCALL(call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *head))); +extern void FASTCALL(call_rcu_bh(struct rcu_head *head, + void (*func)(struct rcu_head *head))); extern void synchronize_kernel(void); #endif /* __KERNEL__ */ |