From 23a9bacd357ab8388c7e07101b186a4282874992 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Sun, 13 Dec 2015 08:57:10 -0800 Subject: [PATCH] rcu: Set rdp->gpwrap when CPU is idle Commit #e3663b1024d1 ("rcu: Handle gpnum/completed wrap while dyntick idle") sets rdp->gpwrap on the wrong side of the "if" statement in dyntick_save_progress_counter(), that is, it sets it when the CPU is not idle instead of when it is idle. Of course, if the CPU is not idle, its rdp->gpnum won't be lagging beind the global rsp->gpnum, which means that rdp->gpwrap will never be set. This commit therefore moves this code to the proper leg of that "if" statement. This change means that the "else" cause is just "return 0" and the "then" clause ends with "return 1", so also move the "return 0" to follow the "if", dropping the "else" clause. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 68f4bee3ecc3..976a166f3fa3 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1083,13 +1083,12 @@ static int dyntick_save_progress_counter(struct rcu_data *rdp, rcu_sysidle_check_cpu(rdp, isidle, maxj); if ((rdp->dynticks_snap & 0x1) == 0) { trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, TPS("dti")); - return 1; - } else { if (ULONG_CMP_LT(READ_ONCE(rdp->gpnum) + ULONG_MAX / 4, rdp->mynode->gpnum)) WRITE_ONCE(rdp->gpwrap, true); - return 0; + return 1; } + return 0; } /* -- 2.20.1