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McKenney" , frederic@kernel.org Subject: [PATCH -rcu dev 2/3] rcu/tree: Fix issue where sometimes rcu_urgent_qs is not set on IPI Date: Thu, 15 Aug 2019 22:53:10 -0400 Message-Id: <20190816025311.241257-2-joel@joelfernandes.org> X-Mailer: git-send-email 2.23.0.rc1.153.gdeed80330f-goog In-Reply-To: <20190816025311.241257-1-joel@joelfernandes.org> References: <20190816025311.241257-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Sometimes I see rcu_urgent_qs is not set. This could be when the last IPI was a long time ago, however, the grace period just started. Set rcu_urgent_qs so the tick can indeed be stopped. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 322b1b57967c..856d3c9f1955 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1091,6 +1091,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) if (tick_nohz_full_cpu(rdp->cpu) && time_after(jiffies, READ_ONCE(rdp->last_fqs_resched) + jtsq * 3)) { + WRITE_ONCE(*ruqp, true); resched_cpu(rdp->cpu); WRITE_ONCE(rdp->last_fqs_resched, jiffies); } -- 2.23.0.rc1.153.gdeed80330f-goog