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rcu: The rcu_gp_cleanup() function does not need cpu_needs_another_gp()

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All of the cpu_needs_another_gp() function's checks (except for
newly arrived callbacks) have been subsumed into the rcu_gp_cleanup()
function's scan of the rcu_node tree.  This commit therefore drops the
call to cpu_needs_another_gp().  The check for newly arrived callbacks
is supplied by rcu_accelerate_cbs().  Any needed advancing (as in the
earlier rcu_advance_cbs() call) will be supplied when the corresponding
CPU becomes aware of the end of the now-completed grace period.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Nicholas Piggin <npiggin@gmail.com>
This commit is contained in:
Paul E. McKenney 2018-04-12 16:16:45 -07:00
parent 665f08f1ce
commit 384f77f4cb
1 changed files with 2 additions and 4 deletions
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6
kernel/rcu/tree.c
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@ -2150,11 +2150,9 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
needgp = true;
}
/* Advance CBs to reduce false positives below. */
needgp = rcu_advance_cbs(rsp, rnp, rdp) || needgp;
if (needgp || cpu_needs_another_gp(rsp, rdp)) {
if (!rcu_accelerate_cbs(rsp, rnp, rdp) && needgp) {
WRITE_ONCE(rsp->gp_flags, RCU_GP_FLAG_INIT);
trace_rcu_grace_period(rsp->name,
READ_ONCE(rsp->gpnum),
trace_rcu_grace_period(rsp->name, READ_ONCE(rsp->gpnum),
TPS("newreq"));
}
WRITE_ONCE(rsp->gp_flags, rsp->gp_flags & RCU_GP_FLAG_INIT);