mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2025-04-12 06:49:52 +00:00
Code Issues Packages Projects Releases Wiki Activity

rcu: Mark callbacks not currently participating in barrier operation

Browse Source 
RCU keeps a count of the number of callbacks that the current
rcu_barrier() is waiting on, but there is currently no easy way to
work out which callback is stuck.  One way to do this is to mark idle
RCU-barrier callbacks by making the ->next pointer point to the callback
itself, and this commit does just that.

Later commits will use this for debug output.

Signed-off-by: "Paul E. McKenney" <paulmck@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadhyay@kernel.org>
This commit is contained in:
Paul E. McKenney 2024-08-01 17:43:01 -07:00 committed by Neeraj Upadhyay
parent 48c21c020f
commit 0616f7e981
1 changed files with 3 additions and 0 deletions

3
kernel/rcu/tree.c

@ -4403,6 +4403,7 @@ static void rcu_barrier_callback(struct rcu_head *rhp)
{
unsigned long __maybe_unused s = rcu_state.barrier_sequence;
rhp->next = rhp; // Mark the callback as having been invoked.
if (atomic_dec_and_test(&rcu_state.barrier_cpu_count)) {
rcu_barrier_trace(TPS("LastCB"), -1, s);
complete(&rcu_state.barrier_completion);
@ -5424,6 +5425,8 @@ static void __init rcu_init_one(void)
while (i > rnp->grphi)
rnp++;
per_cpu_ptr(&rcu_data, i)->mynode = rnp;
per_cpu_ptr(&rcu_data, i)->barrier_head.next =
&per_cpu_ptr(&rcu_data, i)->barrier_head;
rcu_boot_init_percpu_data(i);
}
}