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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-03-10 15:31:55 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2017-04-18 11:38:20 -0700 |
| commit | c2a8ec0778b2ca0d360ba9b5cac7fcd5ddfe798f (patch) | |
| tree | 03f3c9bd515211b30d58cd2d998969e020395ed5 /include/linux/srcu.h | |
| parent | srcu: Push srcu_advance_batches() fastpath into common case (diff) | |
| download | wireguard-linux-c2a8ec0778b2ca0d360ba9b5cac7fcd5ddfe798f.tar.xz wireguard-linux-c2a8ec0778b2ca0d360ba9b5cac7fcd5ddfe798f.zip | |
srcu: Move to state-based grace-period sequencing
The current SRCU grace-period processing might never reach the last
portion of srcu_advance_batches(). This is OK given the current
implementation, as the first portion, up to the try_check_zero()
following the srcu_flip() is sufficient to drive grace periods forward.
However, it has the unfortunate side-effect of making it impossible to
determine when a given grace period has ended, and it will be necessary
to efficiently trace ends of grace periods in order to efficiently handle
per-CPU SRCU callback lists.
This commit therefore adds states to the SRCU grace-period processing,
so that the end of a given SRCU grace period is marked by the transition
to the SRCU_STATE_DONE state.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/srcu.h')
| -rw-r--r-- | include/linux/srcu.h | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/include/linux/srcu.h b/include/linux/srcu.h index a598cf3ac70c..f149a685896c 100644 --- a/include/linux/srcu.h +++ b/include/linux/srcu.h @@ -48,7 +48,7 @@ struct srcu_struct { unsigned long completed; struct srcu_array __percpu *per_cpu_ref; spinlock_t queue_lock; /* protect ->batch_queue, ->running */ - bool running; + int srcu_state; /* callbacks just queued */ struct rcu_batch batch_queue; /* callbacks try to do the first check_zero */ @@ -62,6 +62,12 @@ struct srcu_struct { #endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */ }; +/* Values for -> state variable. */ +#define SRCU_STATE_IDLE 0 +#define SRCU_STATE_SCAN1 1 +#define SRCU_STATE_SCAN2 2 +#define SRCU_STATE_DONE 3 + #ifdef CONFIG_DEBUG_LOCK_ALLOC int __init_srcu_struct(struct srcu_struct *sp, const char *name, @@ -89,7 +95,7 @@ void process_srcu(struct work_struct *work); .completed = -300, \ .per_cpu_ref = &name##_srcu_array, \ .queue_lock = __SPIN_LOCK_UNLOCKED(name.queue_lock), \ - .running = false, \ + .srcu_state = SRCU_STATE_IDLE, \ .batch_queue = RCU_BATCH_INIT(name.batch_queue), \ .batch_check0 = RCU_BATCH_INIT(name.batch_check0), \ .batch_check1 = RCU_BATCH_INIT(name.batch_check1), \ |