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Mon, 07 Sep 2026 00:59:22 -0700 (PDT) From: Kunwu Chan X-Google-Original-From: Kunwu Chan To: paulmck@kernel.org, jiangshanlai@gmail.com, josh@joshtriplett.org Cc: rostedt@goodmis.org, mathieu.desnoyers@efficios.com, rcu@vger.kernel.org, linux-kernel@vger.kernel.org, Kunwu Chan Subject: [PATCH 11/13] srcutree: Remove srcu_barrier() sleep for atomic SRCU Date: Mon, 7 Sep 2026 15:58:27 +0800 Message-ID: <20260907075829.2073224-12-kunwu.chan@linux.dev> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260907075829.2073224-1-kunwu.chan@linux.dev> References: <20260907075829.2073224-1-kunwu.chan@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Kunwu Chan The atomic-SRCU path in srcu_barrier() sleeps for 100 milliseconds just in case there are callbacks to wait for. But call_srcu() refuses atomic SRCU with a WARN_ON_ONCE() before reaching the deferred-enqueue path, so there can be no callbacks, deferred or otherwise. Drop the sleep. Signed-off-by: Kunwu Chan --- kernel/rcu/srcutree.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c index c19f59725706..a93bf803e2f7 100644 --- a/kernel/rcu/srcutree.c +++ b/kernel/rcu/srcutree.c @@ -1895,12 +1895,9 @@ void srcu_barrier(struct srcu_struct *ssp) unsigned long s; check_init_srcu_struct(ssp, false); - if (WARN_ON_ONCE(ssp->srcu_reader_flavor == SRCU_READ_FLAVOR_ATOMIC)) { - // There shouldn't be any callbacks for atomic SRCU, - // but just in case. - schedule_timeout_uninterruptible(HZ/10); + // Atomic SRCU has no callbacks, so there is nothing to wait on. + if (WARN_ON_ONCE(ssp->srcu_reader_flavor == SRCU_READ_FLAVOR_ATOMIC)) return; - } /* * Register any deferred callbacks before snapshotting the sequence. The -- 2.43.0