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author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-11-17 19:27:16 -0800 |
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committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2014-02-17 16:03:09 -0800 |
commit | ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6 (patch) | |
tree | c849b1ea3517d6853b7b4cd386a682187e314f09 | |
parent | 2f33b512a5460578f6cf11d7b7867bed53157c7c (diff) | |
download | linux-stable-ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6.tar.gz linux-stable-ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6.tar.bz2 linux-stable-ffa83fb565fbc397cbafb4b71fd1cce276d4c3b6.zip |
rcu: Optimize rcu_needs_cpu() for RCU_NOCB_CPU_ALL
If CONFIG_RCU_NOCB_CPU_ALL=y, then rcu_needs_cpu() will always
return false, however, the current version nevertheless checks
for RCU callbacks. This commit therefore creates a static inline
implementation of rcu_needs_cpu() that unconditionally returns false
when CONFIG_RCU_NOCB_CPU_ALL=y.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
-rw-r--r-- | include/linux/rcupdate.h | 8 | ||||
-rw-r--r-- | include/linux/rcutiny.h | 6 | ||||
-rw-r--r-- | include/linux/rcutree.h | 2 | ||||
-rw-r--r-- | kernel/rcu/tree.c | 2 | ||||
-rw-r--r-- | kernel/rcu/tree_plugin.h | 4 |
5 files changed, 15 insertions, 7 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 281c90f8989e..5f7d5f410d50 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -1015,6 +1015,14 @@ static inline notrace void rcu_read_unlock_sched_notrace(void) #define kfree_rcu(ptr, rcu_head) \ __kfree_rcu(&((ptr)->rcu_head), offsetof(typeof(*(ptr)), rcu_head)) +#if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL) +static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) +{ + *delta_jiffies = ULONG_MAX; + return 0; +} +#endif /* #if defined(CONFIG_TINY_RCU) || defined(CONFIG_RCU_NOCB_CPU_ALL) */ + #if defined(CONFIG_RCU_NOCB_CPU_ALL) static inline bool rcu_is_nocb_cpu(int cpu) { return true; } #elif defined(CONFIG_RCU_NOCB_CPU) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 6f01771b571c..9524903487d0 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -68,12 +68,6 @@ static inline void kfree_call_rcu(struct rcu_head *head, call_rcu(head, func); } -static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) -{ - *delta_jiffies = ULONG_MAX; - return 0; -} - static inline void rcu_note_context_switch(int cpu) { rcu_sched_qs(cpu); diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 72137ee8c603..81198c84e268 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -31,7 +31,9 @@ #define __LINUX_RCUTREE_H void rcu_note_context_switch(int cpu); +#ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies); +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ void rcu_cpu_stall_reset(void); /* diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index b3d116cd072d..c2c8234a0291 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2880,7 +2880,7 @@ static int rcu_pending(int cpu) * non-NULL, store an indication of whether all callbacks are lazy. * (If there are no callbacks, all of them are deemed to be lazy.) */ -static int rcu_cpu_has_callbacks(int cpu, bool *all_lazy) +static int __maybe_unused rcu_cpu_has_callbacks(int cpu, bool *all_lazy) { bool al = true; bool hc = false; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 39a50b918bff..820b06aefbee 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -1586,11 +1586,13 @@ static void rcu_prepare_kthreads(int cpu) * Because we not have RCU_FAST_NO_HZ, just check whether this CPU needs * any flavor of RCU. */ +#ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) { *delta_jiffies = ULONG_MAX; return rcu_cpu_has_callbacks(cpu, NULL); } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ /* * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up @@ -1696,6 +1698,7 @@ static bool rcu_try_advance_all_cbs(void) * * The caller must have disabled interrupts. */ +#ifndef CONFIG_RCU_NOCB_CPU_ALL int rcu_needs_cpu(int cpu, unsigned long *dj) { struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu); @@ -1726,6 +1729,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj) } return 0; } +#endif /* #ifndef CONFIG_RCU_NOCB_CPU_ALL */ /* * Prepare a CPU for idle from an RCU perspective. The first major task |