From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org,
oleg@redhat.com, paulmck@linux.vnet.ibm.com,
rusty@rustcorp.com.au, mingo@kernel.org,
akpm@linux-foundation.org, namhyung@kernel.org,
walken@google.com, vincent.guittot@linaro.org,
laijs@cn.fujitsu.com
Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com,
xiaoguangrong@linux.vnet.ibm.com, sbw@mit.edu,
fweisbec@gmail.com, zhong@linux.vnet.ibm.com,
nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com,
linux-pm@vger.kernel.org, linux-arch@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 14/45] sched/rt: Use get/put_online_cpus_atomic() to prevent CPU offline
Date: Sun, 23 Jun 2013 19:11:07 +0530 [thread overview]
Message-ID: <20130623134103.19094.5606.stgit@srivatsabhat.in.ibm.com> (raw)
In-Reply-To: <20130623133642.19094.16038.stgit@srivatsabhat.in.ibm.com>
Once stop_machine() is gone from the CPU offline path, we won't be able
to depend on disabling preemption to prevent CPUs from going offline
from under us.
Use the get/put_online_cpus_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
kernel/sched/rt.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 01970c8..03d9f38 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -6,6 +6,7 @@
#include "sched.h"
#include <linux/slab.h>
+#include <linux/cpu.h>
int sched_rr_timeslice = RR_TIMESLICE;
@@ -28,7 +29,9 @@ static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
if (!overrun)
break;
+ get_online_cpus_atomic();
idle = do_sched_rt_period_timer(rt_b, overrun);
+ put_online_cpus_atomic();
}
return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
@@ -547,6 +550,7 @@ static int do_balance_runtime(struct rt_rq *rt_rq)
int i, weight, more = 0;
u64 rt_period;
+ get_online_cpus_atomic();
weight = cpumask_weight(rd->span);
raw_spin_lock(&rt_b->rt_runtime_lock);
@@ -588,6 +592,7 @@ next:
raw_spin_unlock(&iter->rt_runtime_lock);
}
raw_spin_unlock(&rt_b->rt_runtime_lock);
+ put_online_cpus_atomic();
return more;
}
@@ -1168,6 +1173,10 @@ static void yield_task_rt(struct rq *rq)
#ifdef CONFIG_SMP
static int find_lowest_rq(struct task_struct *task);
+/*
+ * Must be called within get/put_online_cpus_atomic(), to prevent CPUs
+ * from going offline from under us.
+ */
static int
select_task_rq_rt(struct task_struct *p, int sd_flag, int flags)
{
@@ -1561,6 +1570,8 @@ retry:
return 0;
}
+ get_online_cpus_atomic();
+
/* We might release rq lock */
get_task_struct(next_task);
@@ -1611,6 +1622,7 @@ retry:
out:
put_task_struct(next_task);
+ put_online_cpus_atomic();
return ret;
}
@@ -1630,6 +1642,7 @@ static int pull_rt_task(struct rq *this_rq)
if (likely(!rt_overloaded(this_rq)))
return 0;
+ get_online_cpus_atomic();
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
@@ -1695,6 +1708,7 @@ skip:
double_unlock_balance(this_rq, src_rq);
}
+ put_online_cpus_atomic();
return ret;
}
next prev parent reply other threads:[~2013-06-23 13:44 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-23 13:37 [PATCH 00/45] CPU hotplug: stop_machine()-free CPU hotplug, part 1 Srivatsa S. Bhat
2013-06-23 13:38 ` [PATCH 01/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context Srivatsa S. Bhat
2013-06-24 22:49 ` Steven Rostedt
2013-06-23 13:38 ` [PATCH 02/45] CPU hotplug: Clarify the usage of different synchronization APIs Srivatsa S. Bhat
2013-06-23 13:38 ` [PATCH 03/45] Documentation, CPU hotplug: Recommend usage of get/put_online_cpus_atomic() Srivatsa S. Bhat
2013-06-23 13:38 ` [PATCH 04/45] CPU hotplug: Add infrastructure to check lacking hotplug synchronization Srivatsa S. Bhat
2013-06-24 23:26 ` Steven Rostedt
2013-06-25 18:49 ` Srivatsa S. Bhat
2013-06-23 13:39 ` [PATCH 05/45] CPU hotplug: Protect set_cpu_online() to avoid false-positives Srivatsa S. Bhat
2013-06-23 13:39 ` [PATCH 06/45] CPU hotplug: Sprinkle debugging checks to catch locking bugs Srivatsa S. Bhat
2013-06-23 13:39 ` [PATCH 07/45] CPU hotplug: Expose the new debug config option Srivatsa S. Bhat
2013-06-23 15:08 ` Sergei Shtylyov
2013-06-23 18:58 ` Srivatsa S. Bhat
2013-06-23 13:39 ` [PATCH 08/45] CPU hotplug: Convert preprocessor macros to static inline functions Srivatsa S. Bhat
2013-06-23 13:40 ` [PATCH 09/45] smp: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-23 13:40 ` [PATCH 10/45] sched/core: " Srivatsa S. Bhat
2013-06-23 13:40 ` [PATCH 11/45] migration: Use raw_spin_lock/unlock since interrupts are already disabled Srivatsa S. Bhat
2013-06-23 13:40 ` [PATCH 12/45] sched/fair: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-23 13:40 ` [PATCH 13/45] timer: " Srivatsa S. Bhat
2013-06-23 13:41 ` Srivatsa S. Bhat [this message]
2013-06-23 13:41 ` [PATCH 15/45] rcu: " Srivatsa S. Bhat
2013-06-23 13:41 ` [PATCH 16/45] tick-broadcast: " Srivatsa S. Bhat
2013-06-23 13:41 ` [PATCH 17/45] time/clocksource: " Srivatsa S. Bhat
2013-06-23 13:42 ` [PATCH 18/45] softirq: " Srivatsa S. Bhat
2013-06-23 13:42 ` [PATCH 19/45] irq: " Srivatsa S. Bhat
2013-06-23 13:42 ` [PATCH 20/45] net: " Srivatsa S. Bhat
2013-06-23 13:42 ` [PATCH 21/45] block: " Srivatsa S. Bhat
2013-06-23 13:42 ` [PATCH 22/45] percpu_counter: " Srivatsa S. Bhat
2013-06-24 17:55 ` Tejun Heo
2013-06-24 18:06 ` Tejun Heo
2013-06-24 18:09 ` Srivatsa S. Bhat
2013-06-23 13:43 ` [PATCH 23/45] infiniband: ehca: " Srivatsa S. Bhat
2013-06-23 13:43 ` [PATCH 24/45] [SCSI] fcoe: " Srivatsa S. Bhat
2013-06-23 13:43 ` [PATCH 25/45] staging/octeon: " Srivatsa S. Bhat
2013-06-23 18:17 ` Greg Kroah-Hartman
2013-06-23 18:55 ` Srivatsa S. Bhat
2013-06-23 19:17 ` Joe Perches
2013-06-24 17:25 ` Srivatsa S. Bhat
2013-06-24 18:17 ` David Daney
2013-06-23 13:43 ` [PATCH 26/45] x86: " Srivatsa S. Bhat
2013-06-23 13:43 ` [PATCH 27/45] perf/x86: " Srivatsa S. Bhat
2013-06-23 13:44 ` [PATCH 28/45] KVM: " Srivatsa S. Bhat
2013-06-23 13:44 ` [PATCH 29/45] kvm/vmx: " Srivatsa S. Bhat
2013-06-23 13:44 ` [PATCH 30/45] x86/xen: " Srivatsa S. Bhat
2013-06-23 13:45 ` [PATCH 31/45] alpha/smp: " Srivatsa S. Bhat
2013-06-23 17:50 ` Matt Turner
2013-06-23 18:56 ` Srivatsa S. Bhat
2013-06-23 13:45 ` [PATCH 32/45] blackfin/smp: " Srivatsa S. Bhat
2013-06-23 13:45 ` [PATCH 33/45] cris/smp: " Srivatsa S. Bhat
2013-06-24 6:41 ` Jesper Nilsson
2013-06-23 13:45 ` [PATCH 34/45] hexagon/smp: " Srivatsa S. Bhat
2013-06-23 13:45 ` [PATCH 35/45] ia64: irq, perfmon: " Srivatsa S. Bhat
2013-06-23 13:46 ` [PATCH 36/45] ia64: smp, tlb: " Srivatsa S. Bhat
2013-06-23 13:46 ` [PATCH 37/45] m32r: " Srivatsa S. Bhat
2013-06-23 13:46 ` [PATCH 38/45] MIPS: " Srivatsa S. Bhat
2013-06-23 13:46 ` [PATCH 39/45] mn10300: " Srivatsa S. Bhat
2013-06-23 13:47 ` [PATCH 40/45] powerpc, irq: Use GFP_ATOMIC allocations in atomic context Srivatsa S. Bhat
2013-06-25 2:08 ` Michael Ellerman
2013-06-25 2:13 ` Benjamin Herrenschmidt
2013-06-25 2:58 ` Michael Ellerman
2013-06-25 3:13 ` Benjamin Herrenschmidt
2013-06-25 19:20 ` Srivatsa S. Bhat
2013-06-23 13:47 ` [PATCH 41/45] powerpc: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-23 13:47 ` [PATCH 42/45] powerpc: Use get/put_online_cpus_atomic() to avoid false-positive warning Srivatsa S. Bhat
2013-06-23 13:47 ` [PATCH 43/45] sh: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-23 13:48 ` [PATCH 44/45] sparc: " Srivatsa S. Bhat
2013-06-23 13:48 ` [PATCH 45/45] tile: " Srivatsa S. Bhat
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