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Wysocki" , Arjan van de Ven , "Paul E . McKenney" , Frederic Weisbecker , Rik van Riel , Steven Rostedt , Sebastian Siewior , Giovanni Gherdovich , Lukasz Luba , "Gautham R . Shenoy" , "Richard Cochran (linutronix GmbH)" , Anna-Maria Behnsen Subject: [PATCH v6 16/21] timer: Restructure internal locking Date: Wed, 10 May 2023 09:28:12 +0200 Message-Id: <20230510072817.116056-17-anna-maria@linutronix.de> In-Reply-To: <20230510072817.116056-1-anna-maria@linutronix.de> References: <20230510072817.116056-1-anna-maria@linutronix.de> MIME-Version: 1.0 X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1765492306081204511?= X-GMAIL-MSGID: =?utf-8?q?1765492306081204511?= From: "Richard Cochran (linutronix GmbH)" Move the locking out from __run_timers() to the call sites, so the protected section can be extended at the call site. Preparatory patch for changing the NOHZ timer placement to a pull at expiry time model. No functional change. Signed-off-by: Richard Cochran (linutronix GmbH) Signed-off-by: Anna-Maria Behnsen --- kernel/time/timer.c | 31 +++++++++++++++++++++---------- 1 file changed, 21 insertions(+), 10 deletions(-) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2370c9a15ba6..61042f1e6f6a 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -2196,11 +2196,7 @@ static inline void __run_timers(struct timer_base *base) struct hlist_head heads[LVL_DEPTH]; int levels; - if (time_before(jiffies, base->next_expiry)) - return; - - timer_base_lock_expiry(base); - raw_spin_lock_irq(&base->lock); + lockdep_assert_held(&base->lock); while (time_after_eq(jiffies, base->clk) && time_after_eq(jiffies, base->next_expiry)) { @@ -2220,21 +2216,36 @@ static inline void __run_timers(struct timer_base *base) while (levels--) expire_timers(base, heads + levels); } +} + +static void __run_timer_base(struct timer_base *base) +{ + if (time_before(jiffies, base->next_expiry)) + return; + + timer_base_lock_expiry(base); + raw_spin_lock_irq(&base->lock); + __run_timers(base); raw_spin_unlock_irq(&base->lock); timer_base_unlock_expiry(base); } +static void run_timer_base(int index) +{ + struct timer_base *base = this_cpu_ptr(&timer_bases[index]); + + __run_timer_base(base); +} + /* * This function runs timers and the timer-tq in bottom half context. */ static __latent_entropy void run_timer_softirq(struct softirq_action *h) { - struct timer_base *base = this_cpu_ptr(&timer_bases[BASE_LOCAL]); - - __run_timers(base); + run_timer_base(BASE_LOCAL); if (IS_ENABLED(CONFIG_NO_HZ_COMMON)) { - __run_timers(this_cpu_ptr(&timer_bases[BASE_GLOBAL])); - __run_timers(this_cpu_ptr(&timer_bases[BASE_DEF])); + run_timer_base(BASE_GLOBAL); + run_timer_base(BASE_DEF); } }