rcu: Don't track sysidle state if no nohz_full= CPUs
If there are no nohz_full= CPUs, then there is currently no reason to track sysidle state. This commit therefore short-circuits this state tracking if !tick_nohz_full_enabled(). Note that these checks will need to be revisited if nohz_full= state can ever be changed at runtime. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com>
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Родитель
417e8d2655
Коммит
663e131090
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@ -2707,6 +2707,10 @@ static void rcu_sysidle_enter(struct rcu_dynticks *rdtp, int irq)
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{
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{
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unsigned long j;
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unsigned long j;
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/* If there are no nohz_full= CPUs, no need to track this. */
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if (!tick_nohz_full_enabled())
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return;
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/* Adjust nesting, check for fully idle. */
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/* Adjust nesting, check for fully idle. */
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if (irq) {
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if (irq) {
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rdtp->dynticks_idle_nesting--;
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rdtp->dynticks_idle_nesting--;
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@ -2772,6 +2776,10 @@ void rcu_sysidle_force_exit(void)
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*/
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*/
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static void rcu_sysidle_exit(struct rcu_dynticks *rdtp, int irq)
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static void rcu_sysidle_exit(struct rcu_dynticks *rdtp, int irq)
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{
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{
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/* If there are no nohz_full= CPUs, no need to track this. */
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if (!tick_nohz_full_enabled())
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return;
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/* Adjust nesting, check for already non-idle. */
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/* Adjust nesting, check for already non-idle. */
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if (irq) {
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if (irq) {
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rdtp->dynticks_idle_nesting++;
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rdtp->dynticks_idle_nesting++;
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@ -2826,6 +2834,10 @@ static void rcu_sysidle_check_cpu(struct rcu_data *rdp, bool *isidle,
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unsigned long j;
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unsigned long j;
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struct rcu_dynticks *rdtp = rdp->dynticks;
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struct rcu_dynticks *rdtp = rdp->dynticks;
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/* If there are no nohz_full= CPUs, don't check system-wide idleness. */
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if (!tick_nohz_full_enabled())
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return;
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/*
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/*
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* If some other CPU has already reported non-idle, if this is
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* If some other CPU has already reported non-idle, if this is
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* not the flavor of RCU that tracks sysidle state, or if this
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* not the flavor of RCU that tracks sysidle state, or if this
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@ -2952,6 +2964,10 @@ static void rcu_sysidle_report(struct rcu_state *rsp, int isidle,
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static void rcu_sysidle_report_gp(struct rcu_state *rsp, int isidle,
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static void rcu_sysidle_report_gp(struct rcu_state *rsp, int isidle,
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unsigned long maxj)
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unsigned long maxj)
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{
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{
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/* If there are no nohz_full= CPUs, no need to track this. */
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if (!tick_nohz_full_enabled())
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return;
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rcu_sysidle_report(rsp, isidle, maxj, true);
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rcu_sysidle_report(rsp, isidle, maxj, true);
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}
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}
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@ -2978,7 +2994,8 @@ static void rcu_sysidle_cb(struct rcu_head *rhp)
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/*
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/*
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* Check to see if the system is fully idle, other than the timekeeping CPU.
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* Check to see if the system is fully idle, other than the timekeeping CPU.
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* The caller must have disabled interrupts.
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* The caller must have disabled interrupts. This is not intended to be
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* called unless tick_nohz_full_enabled().
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*/
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*/
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bool rcu_sys_is_idle(void)
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bool rcu_sys_is_idle(void)
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{
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{
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