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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-03-27 08:44:00 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2013-06-10 13:45:49 -0700 |
| commit | 127781d1ba1ee5bbe1780afa35dd0e71583b143d (patch) | |
| tree | 3c9b5961bc02e7f380a7bd7932181329ecbec397 /include | |
| parent | efc151c33b971148894789dc7c5589dec46d4348 (diff) | |
| download | lwn-127781d1ba1ee5bbe1780afa35dd0e71583b143d.tar.gz lwn-127781d1ba1ee5bbe1780afa35dd0e71583b143d.zip | |
rcu: Remove TINY_PREEMPT_RCU
TINY_PREEMPT_RCU adds significant code and complexity, but does not
offer commensurate benefits. People currently using TINY_PREEMPT_RCU
can get much better memory footprint with TINY_RCU, or, if they really
need preemptible RCU, they can use TREE_PREEMPT_RCU with a relatively
minor degradation in memory footprint. Please note that this move
has been widely publicized on LKML (https://lkml.org/lkml/2012/11/12/545)
and on LWN (http://lwn.net/Articles/541037/).
This commit therefore removes TINY_PREEMPT_RCU.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
[ paulmck: Updated to eliminate #else in rcutiny.h as suggested by Josh ]
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/hardirq.h | 2 | ||||
| -rw-r--r-- | include/linux/rcupdate.h | 2 | ||||
| -rw-r--r-- | include/linux/rcutiny.h | 24 |
3 files changed, 4 insertions, 24 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index c1d6555d2567..05bcc0903766 100644 --- a/include/linux/hardirq.h +++ b/include/linux/hardirq.h @@ -128,7 +128,7 @@ extern void synchronize_irq(unsigned int irq); # define synchronize_irq(irq) barrier() #endif -#if defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) +#if defined(CONFIG_TINY_RCU) static inline void rcu_nmi_enter(void) { diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index ddcc7826d907..70b1522badd3 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -277,7 +277,7 @@ void wait_rcu_gp(call_rcu_func_t crf); #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) #include <linux/rcutree.h> -#elif defined(CONFIG_TINY_RCU) || defined(CONFIG_TINY_PREEMPT_RCU) +#elif defined(CONFIG_TINY_RCU) #include <linux/rcutiny.h> #else #error "Unknown RCU implementation specified to kernel configuration" diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 4e56a9c69a35..d3c094ffa960 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -53,16 +53,7 @@ static inline void rcu_barrier(void) rcu_barrier_sched(); /* Only one CPU, so only one list of callbacks! */ } -#else /* #ifdef CONFIG_TINY_RCU */ - -void synchronize_rcu_expedited(void); - -static inline void rcu_barrier(void) -{ - wait_rcu_gp(call_rcu); -} - -#endif /* #else #ifdef CONFIG_TINY_RCU */ +#endif /* #ifdef CONFIG_TINY_RCU */ static inline void synchronize_rcu_bh(void) { @@ -97,18 +88,7 @@ static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) return 0; } -#else /* #ifdef CONFIG_TINY_RCU */ - -void rcu_preempt_note_context_switch(void); -int rcu_preempt_needs_cpu(void); - -static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies) -{ - *delta_jiffies = ULONG_MAX; - return rcu_preempt_needs_cpu(); -} - -#endif /* #else #ifdef CONFIG_TINY_RCU */ +#endif /* #ifdef CONFIG_TINY_RCU */ static inline void rcu_note_context_switch(int cpu) { |