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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-05-16 00:24:41 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-07-13 00:38:55 +0200 |
| commit | d72193123c81ae6123d108b3be2096f3f13b25a6 (patch) | |
| tree | 2ec9801c5c3b7c1f9411ba3a1bc6005d1f154198 /kernel/rcu/rcu.h | |
| parent | rcu: Make rcu_start_this_gp() check for grace period already started (diff) | |
| download | linux-d72193123c81ae6123d108b3be2096f3f13b25a6.tar.xz linux-d72193123c81ae6123d108b3be2096f3f13b25a6.zip | |
rcutorture: Correctly handle grace-period sequence wrap
The new ->gq_seq grace-period sequence numbers must be shifted down,
which give artifacts when these numbers wrap. This commit therefore
enables rcutorture and rcuperf to handle grace-period sequence numbers
even if they do wrap. It does this by allowing a special subtraction
function to be specified, and this function subtracts before shifting.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/rcu.h')
| -rw-r--r-- | kernel/rcu/rcu.h | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index 1c5cbd9d7c97..aa215d6355f8 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -143,6 +143,15 @@ static inline bool rcu_seq_new_gp(unsigned long old, unsigned long new) } /* + * Roughly how many full grace periods have elapsed between the collection + * of the two specified grace periods? + */ +static inline unsigned long rcu_seq_diff(unsigned long new, unsigned long old) +{ + return (new - old) >> RCU_SEQ_CTR_SHIFT; +} + +/* * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally * by call_rcu() and rcu callback execution, and are therefore not part of the * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors. |