From: Paul E. McKenney Date: Thu, 12 Apr 2018 23:16:45 +0000 (-0700) Subject: rcu: The rcu_gp_cleanup() function does not need cpu_needs_another_gp() X-Git-Tag: v4.18-rc1~169^2~1^2^3~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=384f77f4cb765707216ea43f9122580d8a07be7d;p=thirdparty%2Fkernel%2Flinux.git rcu: The rcu_gp_cleanup() function does not need cpu_needs_another_gp() 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 Tested-by: Nicholas Piggin --- diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 07bccb1f0c877..7776d709e0605 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -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);