diff mbox series

[1/3] srcu: Remove superfluous callbacks advancing from srcu_gp_start()

Message ID 20231212174817.11919-1-neeraj.iitr10@gmail.com (mailing list archive)
State Mainlined
Commit 20eb4142397cf3ec221de43f10ea149af462c572
Headers show
Series SRCU updates for v6.8 | expand

Commit Message

Neeraj Upadhyay (AMD) Dec. 12, 2023, 5:48 p.m. UTC 
From: Frederic Weisbecker <frederic@kernel.org>

Callbacks advancing on SRCU must be performed on two specific places:

1) On enqueue time in order to make room for the acceleration of the
   new callback.

2) On invocation time in order to move the callbacks ready to invoke.

Any other callback advancing callsite is needless. Remove the remaining
one in srcu_gp_start().

Co-developed-by: Yong He <zhuangel570@gmail.com>
Signed-off-by: Yong He <zhuangel570@gmail.com>
Co-developed-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Joel Fernandes <joel@joelfernandes.org>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Co-developed-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.iitr10@gmail.com>
---
 kernel/rcu/srcutree.c | 10 ----------
 1 file changed, 10 deletions(-)
diff mbox series

Patch

diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
index 560e99ec5333..e9356a103626 100644
--- a/kernel/rcu/srcutree.c
+++ b/kernel/rcu/srcutree.c
@@ -772,20 +772,10 @@  EXPORT_SYMBOL_GPL(__srcu_read_unlock_nmisafe);
  */
 static void srcu_gp_start(struct srcu_struct *ssp)
 {
-	struct srcu_data *sdp;
 	int state;
 
-	if (smp_load_acquire(&ssp->srcu_sup->srcu_size_state) < SRCU_SIZE_WAIT_BARRIER)
-		sdp = per_cpu_ptr(ssp->sda, get_boot_cpu_id());
-	else
-		sdp = this_cpu_ptr(ssp->sda);
 	lockdep_assert_held(&ACCESS_PRIVATE(ssp->srcu_sup, lock));
 	WARN_ON_ONCE(ULONG_CMP_GE(ssp->srcu_sup->srcu_gp_seq, ssp->srcu_sup->srcu_gp_seq_needed));
-	spin_lock_rcu_node(sdp);  /* Interrupts already disabled. */
-	rcu_segcblist_advance(&sdp->srcu_cblist,
-			      rcu_seq_current(&ssp->srcu_sup->srcu_gp_seq));
-	WARN_ON_ONCE(!rcu_segcblist_segempty(&sdp->srcu_cblist, RCU_NEXT_TAIL));
-	spin_unlock_rcu_node(sdp);  /* Interrupts remain disabled. */
 	WRITE_ONCE(ssp->srcu_sup->srcu_gp_start, jiffies);
 	WRITE_ONCE(ssp->srcu_sup->srcu_n_exp_nodelay, 0);
 	smp_mb(); /* Order prior store to ->srcu_gp_seq_needed vs. GP start. */