lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 20 Dec 2010 16:24:13 +0100 From: Frederic Weisbecker <fweisbec@...il.com> To: LKML <linux-kernel@...r.kernel.org> Cc: LKML <linux-kernel@...r.kernel.org>, Frederic Weisbecker <fweisbec@...il.com>, Thomas Gleixner <tglx@...utronix.de>, Peter Zijlstra <a.p.zijlstra@...llo.nl>, "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>, Ingo Molnar <mingo@...e.hu>, Steven Rostedt <rostedt@...dmis.org>, Lai Jiangshan <laijs@...fujitsu.com>, Andrew Morton <akpm@...ux-foundation.org>, Anton Blanchard <anton@....ibm.com>, Tim Pepper <lnxninja@...ux.vnet.ibm.com> Subject: [RFC PATCH 06/15] nohz_task: Keep the tick if rcu needs it When a nohz task is running, don't stop the tick if RCU needs the CPU to notify a quiescent state or if it has callbacks to handle. Signed-off-by: Frederic Weisbecker <fweisbec@...il.com> Cc: Thomas Gleixner <tglx@...utronix.de> Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl> Cc: Paul E. McKenney <paulmck@...ux.vnet.ibm.com> Cc: Ingo Molnar <mingo@...e.hu> Cc: Steven Rostedt <rostedt@...dmis.org> Cc: Lai Jiangshan <laijs@...fujitsu.com> Cc: Andrew Morton <akpm@...ux-foundation.org> Cc: Anton Blanchard <anton@....ibm.com> Cc: Tim Pepper <lnxninja@...ux.vnet.ibm.com> --- include/linux/rcupdate.h | 1 + kernel/rcutree.c | 3 +-- kernel/sched.c | 6 ++++++ 3 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 03cda7b..262d48b 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -122,6 +122,7 @@ extern void rcu_init(void); extern void rcu_sched_qs(int cpu); extern void rcu_bh_qs(int cpu); extern void rcu_check_callbacks(int cpu, int user); +extern int rcu_pending(int cpu); struct notifier_block; #ifdef CONFIG_NO_HZ diff --git a/kernel/rcutree.c b/kernel/rcutree.c index ccdc04c..44dce3f 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -149,7 +149,6 @@ module_param(rcu_cpu_stall_suppress, int, 0644); #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */ static void force_quiescent_state(struct rcu_state *rsp, int relaxed); -static int rcu_pending(int cpu); /* * Return the number of RCU-sched batches processed thus far for debug & stats. @@ -1634,7 +1633,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) * by the current CPU, returning 1 if so. This function is part of the * RCU implementation; it is -not- an exported member of the RCU API. */ -static int rcu_pending(int cpu) +int rcu_pending(int cpu) { return __rcu_pending(&rcu_sched_state, &per_cpu(rcu_sched_data, cpu)) || __rcu_pending(&rcu_bh_state, &per_cpu(rcu_bh_data, cpu)) || diff --git a/kernel/sched.c b/kernel/sched.c index 6dbae46..45bd6e2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2470,10 +2470,16 @@ static void nohz_task_cpu_update(void *unused) int nohz_task_can_stop_tick(void) { struct rq *rq = this_rq(); + int cpu; if (rq->nr_running > 1) return 0; + cpu = smp_processor_id(); + + if (rcu_pending(cpu) || rcu_needs_cpu(cpu)) + return 0; + return 1; } -- 1.7.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists