Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753455AbdHWBw6 (ORCPT ); Tue, 22 Aug 2017 21:52:58 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:33778 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753302AbdHWBvc (ORCPT ); Tue, 22 Aug 2017 21:51:32 -0400 From: Frederic Weisbecker To: LKML Cc: Frederic Weisbecker , Peter Zijlstra , Chris Metcalf , Thomas Gleixner , Luiz Capitulino , Christoph Lameter , "Paul E . McKenney" , Ingo Molnar , Mike Galbraith , Rik van Riel , Wanpeng Li Subject: [RFC PATCH 08/12] housekeeping: Introduce housekeeping flags Date: Wed, 23 Aug 2017 03:51:07 +0200 Message-Id: <1503453071-952-9-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1503453071-952-1-git-send-email-fweisbec@gmail.com> References: <1503453071-952-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8270 Lines: 251 Before we implement isolcpus under housekeeping, we need the isolation features to be more finegrained. For example some people want nohz_full without the full scheduler isolation, others want full scheduler isolation without nohz_full. So let's cut all these isolation features piecewise, at the risk of overcutting it right now. We can still merge some flags later if they always make sense together. Signed-off-by: Frederic Weisbecker Cc: Chris Metcalf Cc: Rik van Riel Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Mike Galbraith Cc: Ingo Molnar Cc: Christoph Lameter Cc: Paul E. McKenney Cc: Wanpeng Li Cc: Luiz Capitulino --- drivers/net/ethernet/tile/tilegx.c | 4 ++-- include/linux/housekeeping.h | 26 +++++++++++++++++--------- kernel/housekeeping.c | 26 +++++++++++++++----------- kernel/rcu/tree_plugin.h | 2 +- kernel/rcu/update.c | 2 +- kernel/sched/core.c | 8 ++++---- kernel/sched/fair.c | 2 +- kernel/watchdog.c | 3 ++- 8 files changed, 43 insertions(+), 30 deletions(-) diff --git a/drivers/net/ethernet/tile/tilegx.c b/drivers/net/ethernet/tile/tilegx.c index eb74e09..0bd765b 100644 --- a/drivers/net/ethernet/tile/tilegx.c +++ b/drivers/net/ethernet/tile/tilegx.c @@ -2270,8 +2270,8 @@ static int __init tile_net_init_module(void) tile_net_dev_init(name, mac); if (!network_cpus_init()) - cpumask_and(&network_cpus_map, housekeeping_cpumask(), - cpu_online_mask); + cpumask_and(&network_cpus_map, + housekeeping_cpumask(HK_FLAG_MISC), cpu_online_mask); return 0; } diff --git a/include/linux/housekeeping.h b/include/linux/housekeeping.h index dcbec47..b1a62544 100644 --- a/include/linux/housekeeping.h +++ b/include/linux/housekeeping.h @@ -5,35 +5,43 @@ #include #include +enum hk_flags { + HK_FLAG_TIMER = 1, + HK_FLAG_RCU = (1 << 1), + HK_FLAG_MISC = (1 << 2), + HK_FLAG_SCHED = (1 << 3), +}; + #ifdef CONFIG_CPU_ISOLATION DECLARE_STATIC_KEY_FALSE(housekeeping_overriden); -extern int housekeeping_any_cpu(void); -extern const struct cpumask *housekeeping_cpumask(void); -extern void housekeeping_affine(struct task_struct *t); -extern bool housekeeping_test_cpu(int cpu); +extern int housekeeping_any_cpu(enum hk_flags flags); +extern const struct cpumask *housekeeping_cpumask(enum hk_flags flags); +extern void housekeeping_affine(struct task_struct *t, enum hk_flags flags); +extern bool housekeeping_test_cpu(int cpu, enum hk_flags flags); extern void __init housekeeping_init(void); #else -static inline int housekeeping_any_cpu(void) +static inline int housekeeping_any_cpu(enum hk_flags flags) { return smp_processor_id(); } -static inline const struct cpumask *housekeeping_cpumask(void) +static inline const struct cpumask *housekeeping_cpumask(enum hk_flags flags) { return cpu_possible_mask; } -static inline void housekeeping_affine(struct task_struct *t) { } +static inline void housekeeping_affine(struct task_struct *t, + enum hk_flags flags) { } static inline void housekeeping_init(void) { } #endif /* CONFIG_CPU_ISOLATION */ -static inline bool housekeeping_cpu(int cpu) +static inline bool housekeeping_cpu(int cpu, enum hk_flags flags) { #ifdef CONFIG_CPU_ISOLATION if (static_branch_unlikely(&housekeeping_overriden)) - return housekeeping_test_cpu(cpu); + return housekeeping_test_cpu(cpu, flags); #endif return true; } diff --git a/kernel/housekeeping.c b/kernel/housekeeping.c index f8be7e6..e2196d1 100644 --- a/kernel/housekeeping.c +++ b/kernel/housekeeping.c @@ -14,34 +14,36 @@ DEFINE_STATIC_KEY_FALSE(housekeeping_overriden); EXPORT_SYMBOL_GPL(housekeeping_overriden); static cpumask_var_t housekeeping_mask; +static unsigned int housekeeping_flags; -int housekeeping_any_cpu(void) +int housekeeping_any_cpu(enum hk_flags flags) { if (static_branch_unlikely(&housekeeping_overriden)) - return cpumask_any_and(housekeeping_mask, cpu_online_mask); - + if (housekeeping_flags & flags) + return cpumask_any_and(housekeeping_mask, cpu_online_mask); return smp_processor_id(); } -const struct cpumask *housekeeping_cpumask(void) +const struct cpumask *housekeeping_cpumask(enum hk_flags flags) { if (static_branch_unlikely(&housekeeping_overriden)) - return housekeeping_mask; - + if (housekeeping_flags & flags) + return housekeeping_mask; return cpu_possible_mask; } -void housekeeping_affine(struct task_struct *t) +void housekeeping_affine(struct task_struct *t, enum hk_flags flags) { if (static_branch_unlikely(&housekeeping_overriden)) - set_cpus_allowed_ptr(t, housekeeping_mask); + if (housekeeping_flags & flags) + set_cpus_allowed_ptr(t, housekeeping_mask); } -bool housekeeping_test_cpu(int cpu) +bool housekeeping_test_cpu(int cpu, enum hk_flags flags) { if (static_branch_unlikely(&housekeeping_overriden)) - return cpumask_test_cpu(cpu, housekeeping_mask); - + if (housekeeping_flags & flags) + return cpumask_test_cpu(cpu, housekeeping_mask); return true; } @@ -60,6 +62,8 @@ void __init housekeeping_init(void) cpumask_andnot(housekeeping_mask, cpu_possible_mask, tick_nohz_full_mask); + housekeeping_flags = HK_FLAG_TIMER | HK_FLAG_RCU | HK_FLAG_MISC; + static_branch_enable(&housekeeping_overriden); /* We need at least one CPU to handle housekeeping work */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index c66d162..47f2865 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2542,7 +2542,7 @@ static void rcu_bind_gp_kthread(void) if (!tick_nohz_full_enabled()) return; - housekeeping_affine(current); + housekeeping_affine(current, HK_FLAG_RCU); } /* Record the current task on dyntick-idle entry. */ diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c index bfe973d..7acfd74 100644 --- a/kernel/rcu/update.c +++ b/kernel/rcu/update.c @@ -719,7 +719,7 @@ static int __noreturn rcu_tasks_kthread(void *arg) LIST_HEAD(rcu_tasks_holdouts); /* Run on housekeeping CPUs by default. Sysadm can move if desired. */ - housekeeping_affine(current); + housekeeping_affine(current, HK_FLAG_RCU); /* * Each pass through the following loop makes one check for diff --git a/kernel/sched/core.c b/kernel/sched/core.c index fd00ae3..877c85d 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -527,7 +527,7 @@ int get_nohz_timer_target(void) int i, cpu = smp_processor_id(); struct sched_domain *sd; - if (!idle_cpu(cpu) && housekeeping_cpu(cpu)) + if (!idle_cpu(cpu) && housekeeping_cpu(cpu, HK_FLAG_TIMER)) return cpu; rcu_read_lock(); @@ -536,15 +536,15 @@ int get_nohz_timer_target(void) if (cpu == i) continue; - if (!idle_cpu(i) && housekeeping_cpu(i)) { + if (!idle_cpu(i) && housekeeping_cpu(i, HK_FLAG_TIMER)) { cpu = i; goto unlock; } } } - if (!housekeeping_cpu(cpu)) - cpu = housekeeping_any_cpu(); + if (!housekeeping_cpu(cpu, HK_FLAG_TIMER)) + cpu = housekeeping_any_cpu(HK_FLAG_TIMER); unlock: rcu_read_unlock(); return cpu; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 0d8f7b1..74af955 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -8739,7 +8739,7 @@ void nohz_balance_enter_idle(int cpu) return; /* Spare idle load balancing on CPUs that don't want to be disturbed: */ - if (!housekeeping_cpu(cpu)) + if (!housekeeping_cpu(cpu, HK_FLAG_SCHED)) return; if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu))) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index cdd0d11..631131c 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -944,7 +944,8 @@ void __init lockup_detector_init(void) if (tick_nohz_full_enabled()) pr_info("Disabling watchdog on nohz_full cores by default\n"); - cpumask_copy(&watchdog_cpumask, housekeeping_cpumask()); + cpumask_copy(&watchdog_cpumask, + housekeeping_cpumask(HK_FLAG_TIMER)); if (watchdog_enabled) watchdog_enable_all_cpus(); -- 2.7.4