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author | Frederic Weisbecker <fweisbec@gmail.com> | 2012-06-04 23:42:35 (GMT) |
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committer | Frederic Weisbecker <fweisbec@gmail.com> | 2012-09-26 13:44:01 (GMT) |
commit | 19dd1591fc379f1d89f39cd99cbbe97433baa3c3 (patch) | |
tree | 9c298c4c0f38e68f53c2e4a13080fbec1282953f /include | |
parent | adf5091e6ccaa02905e7a28f9ff44f46c7f4c230 (diff) | |
download | linux-fsl-qoriq-19dd1591fc379f1d89f39cd99cbbe97433baa3c3.tar.xz |
rcu: New rcu_user_enter_after_irq() and rcu_user_exit_after_irq() APIs
In some cases, it is necessary to enter or exit userspace-RCU-idle mode
from an interrupt handler, for example, if some other CPU sends this
CPU a resched IPI. In this case, the current CPU would enter the IPI
handler in userspace-RCU-idle mode, but would need to exit the IPI handler
after having exited that mode.
To allow this to work, this commit adds two new APIs to TREE_RCU:
- rcu_user_enter_after_irq(). This must be called from an interrupt between
rcu_irq_enter() and rcu_irq_exit(). After the irq calls rcu_irq_exit(),
the irq handler will return into an RCU extended quiescent state.
In theory, this interrupt is never a nested interrupt, but in practice
it might interrupt softirq, which looks to RCU like a nested interrupt.
- rcu_user_exit_after_irq(). This must be called from a non-nesting
interrupt, interrupting an RCU extended quiescent state, also
between rcu_irq_enter() and rcu_irq_exit(). After the irq calls
rcu_irq_exit(), the irq handler will return in an RCU non-quiescent
state.
[ Combined with "Allow calls to rcu_exit_user_irq from nesting irqs." ]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/rcupdate.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index d8b20bf..f818dd1 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -193,6 +193,8 @@ extern void rcu_irq_enter(void); extern void rcu_irq_exit(void); extern void rcu_user_enter(void); extern void rcu_user_exit(void); +extern void rcu_user_enter_after_irq(void); +extern void rcu_user_exit_after_irq(void); extern void exit_rcu(void); /** |