diff options
| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-10-31 00:59:01 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-12-07 17:01:31 -0800 |
| commit | 7c9906ca5e582a773fff696975e312cef58a7386 (patch) | |
| tree | 1155e2ed10709b9d3efa87b2f4b826cc886e84eb /include/linux | |
| parent | rcu: Make cpu_needs_another_gp() be bool (diff) | |
| download | linux-dev-7c9906ca5e582a773fff696975e312cef58a7386.tar.xz linux-dev-7c9906ca5e582a773fff696975e312cef58a7386.zip | |
rcu: Don't redundantly disable irqs in rcu_irq_{enter,exit}()
This commit replaces a local_irq_save()/local_irq_restore() pair with
a lockdep assertion that interrupts are already disabled. This should
remove the corresponding overhead from the interrupt entry/exit fastpaths.
This change was inspired by the fact that Iftekhar Ahmed's mutation
testing showed that removing rcu_irq_enter()'s call to local_ird_restore()
had no effect, which might indicate that interrupts were always enabled
anyway.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/rcupdate.h | 4 | ||||
| -rw-r--r-- | include/linux/rcutiny.h | 8 | ||||
| -rw-r--r-- | include/linux/rcutree.h | 2 | ||||
| -rw-r--r-- | include/linux/tracepoint.h | 4 |
4 files changed, 14 insertions, 4 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index a0189ba67fde..f2b667df1131 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -379,9 +379,9 @@ static inline void rcu_init_nohz(void) */ #define RCU_NONIDLE(a) \ do { \ - rcu_irq_enter(); \ + rcu_irq_enter_irqson(); \ do { a; } while (0); \ - rcu_irq_exit(); \ + rcu_irq_exit_irqson(); \ } while (0) /* diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 4c1aaf9cce7b..64809aea661c 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -181,6 +181,14 @@ static inline void rcu_irq_enter(void) { } +static inline void rcu_irq_exit_irqson(void) +{ +} + +static inline void rcu_irq_enter_irqson(void) +{ +} + static inline void rcu_irq_exit(void) { } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 9d3eda39bcd2..ad1eda9fa4da 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -97,6 +97,8 @@ void rcu_idle_enter(void); void rcu_idle_exit(void); void rcu_irq_enter(void); void rcu_irq_exit(void); +void rcu_irq_enter_irqson(void); +void rcu_irq_exit_irqson(void); void exit_rcu(void); diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 696a339c592c..7834a8a8bf1e 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -171,8 +171,8 @@ extern void syscall_unregfunc(void); TP_PROTO(data_proto), \ TP_ARGS(data_args), \ TP_CONDITION(cond), \ - rcu_irq_enter(), \ - rcu_irq_exit()); \ + rcu_irq_enter_irqson(), \ + rcu_irq_exit_irqson()); \ } #else #define __DECLARE_TRACE_RCU(name, proto, args, cond, data_proto, data_args) |