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: linux-arch@vger.kernel.org, nikunj@linux.vnet.ibm.com,
zhong@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
fweisbec@gmail.com, linux-kernel@vger.kernel.org,
rostedt@goodmis.org, xiaoguangrong@linux.vnet.ibm.com,
sbw@mit.edu, John Stultz <john.stultz@linaro.org>,
wangyun@linux.vnet.ibm.com,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
netdev@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 17/45] time/clocksource: Use get/put_online_cpus_atomic() to prevent CPU offline
Date: Wed, 26 Jun 2013 01:58:20 +0530 [thread overview]
Message-ID: <20130625202820.16593.17778.stgit@srivatsabhat.in.ibm.com> (raw)
In-Reply-To: <20130625202452.16593.22810.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: John Stultz <john.stultz@linaro.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
kernel/time/clocksource.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e713ef7..c4bbc25 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -30,6 +30,7 @@
#include <linux/sched.h> /* for spin_unlock_irq() using preempt_count() m68k */
#include <linux/tick.h>
#include <linux/kthread.h>
+#include <linux/cpu.h>
#include "tick-internal.h"
@@ -252,6 +253,7 @@ static void clocksource_watchdog(unsigned long data)
int64_t wd_nsec, cs_nsec;
int next_cpu, reset_pending;
+ get_online_cpus_atomic();
spin_lock(&watchdog_lock);
if (!watchdog_running)
goto out;
@@ -329,6 +331,7 @@ static void clocksource_watchdog(unsigned long data)
add_timer_on(&watchdog_timer, next_cpu);
out:
spin_unlock(&watchdog_lock);
+ put_online_cpus_atomic();
}
static inline void clocksource_start_watchdog(void)
@@ -367,6 +370,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
{
unsigned long flags;
+ get_online_cpus_atomic();
spin_lock_irqsave(&watchdog_lock, flags);
if (cs->flags & CLOCK_SOURCE_MUST_VERIFY) {
/* cs is a clocksource to be watched. */
@@ -386,6 +390,7 @@ static void clocksource_enqueue_watchdog(struct clocksource *cs)
/* Check if the watchdog timer needs to be started. */
clocksource_start_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
+ put_online_cpus_atomic();
}
static void clocksource_dequeue_watchdog(struct clocksource *cs)
next prev parent reply other threads:[~2013-06-25 20:31 UTC|newest]
Thread overview: 72+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-25 20:25 [PATCH v2 00/45] CPU hotplug: stop_machine()-free CPU hotplug, part 1 Srivatsa S. Bhat
2013-06-25 20:25 ` [PATCH v2 01/45] CPU hotplug: Provide APIs to prevent CPU offline from atomic context Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 02/45] CPU hotplug: Clarify the usage of different synchronization APIs Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 03/45] Documentation, CPU hotplug: Recommend usage of get/put_online_cpus_atomic() Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 04/45] CPU hotplug: Add infrastructure to check lacking hotplug synchronization Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 05/45] CPU hotplug: Protect set_cpu_online() to avoid false-positives Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 06/45] CPU hotplug: Sprinkle debugging checks to catch locking bugs Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 07/45] CPU hotplug: Expose the new debug config option Srivatsa S. Bhat
2013-06-25 20:26 ` [PATCH v2 08/45] CPU hotplug: Convert preprocessor macros to static inline functions Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 09/45] smp: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 10/45] sched/core: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 11/45] migration: Use raw_spin_lock/unlock since interrupts are already disabled Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 12/45] sched/fair: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 13/45] timer: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 14/45] sched/rt: " Srivatsa S. Bhat
2013-06-25 20:27 ` [PATCH v2 15/45] rcu: " Srivatsa S. Bhat
2013-06-25 22:00 ` Paul E. McKenney
2013-06-26 14:09 ` Srivatsa S. Bhat
2013-06-26 14:29 ` David Laight
2013-06-26 14:34 ` Paul E. McKenney
2013-06-26 14:51 ` Steven Rostedt
2013-06-26 15:21 ` Tejun Heo
2013-06-26 15:33 ` Steven Rostedt
2013-06-26 17:29 ` Tejun Heo
2013-06-26 18:28 ` Srivatsa S. Bhat
2013-06-26 21:34 ` Tejun Heo
2013-06-27 6:53 ` Srivatsa S. Bhat
2013-06-26 18:22 ` Srivatsa S. Bhat
2013-06-27 8:54 ` David Laight
2013-06-27 10:06 ` Srivatsa S. Bhat
2013-06-26 14:45 ` Paul E. McKenney
2013-06-26 18:18 ` Srivatsa S. Bhat
2013-06-26 14:33 ` Paul E. McKenney
2013-06-25 20:28 ` [PATCH v2 16/45] tick-broadcast: " Srivatsa S. Bhat
2013-06-25 20:28 ` Srivatsa S. Bhat [this message]
2013-06-25 20:28 ` [PATCH v2 18/45] softirq: " Srivatsa S. Bhat
2013-06-25 20:28 ` [PATCH v2 19/45] irq: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 20/45] net: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 21/45] block: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 22/45] percpu_counter: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 23/45] infiniband: ehca: " Srivatsa S. Bhat
2013-06-25 20:29 ` [PATCH v2 24/45] [SCSI] fcoe: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 25/45] staging/octeon: " Srivatsa S. Bhat
2013-06-25 20:45 ` Greg Kroah-Hartman
2013-06-25 20:30 ` [PATCH v2 26/45] x86: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 27/45] perf/x86: " Srivatsa S. Bhat
2013-06-25 20:30 ` [PATCH v2 28/45] KVM: " Srivatsa S. Bhat
2013-06-26 8:20 ` Paolo Bonzini
2013-06-25 20:30 ` [PATCH v2 29/45] kvm/vmx: " Srivatsa S. Bhat
2013-06-26 7:46 ` Paolo Bonzini
2013-06-26 8:06 ` Srivatsa S. Bhat
2013-06-26 8:23 ` Paolo Bonzini
2013-06-26 8:41 ` Srivatsa S. Bhat
2013-06-26 8:57 ` Paolo Bonzini
2013-06-25 20:30 ` [PATCH v2 30/45] x86/xen: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 31/45] alpha/smp: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 32/45] blackfin/smp: " Srivatsa S. Bhat
2013-06-25 20:31 ` [PATCH v2 33/45] cris/smp: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 34/45] hexagon/smp: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 35/45] ia64: irq, perfmon: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 36/45] ia64: smp, tlb: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 37/45] m32r: " Srivatsa S. Bhat
2013-06-25 20:32 ` [PATCH v2 38/45] MIPS: " Srivatsa S. Bhat
2013-06-26 13:39 ` Ralf Baechle
2013-06-27 7:08 ` Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 39/45] mn10300: " Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 40/45] powerpc, irq: Use GFP_ATOMIC allocations in atomic context Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 41/45] powerpc: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 42/45] powerpc: Use get/put_online_cpus_atomic() to avoid false-positive warning Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 43/45] sh: Use get/put_online_cpus_atomic() to prevent CPU offline Srivatsa S. Bhat
2013-06-25 20:33 ` [PATCH v2 44/45] sparc: " Srivatsa S. Bhat
2013-06-25 20:34 ` [PATCH v2 45/45] tile: " Srivatsa S. Bhat
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130625202820.16593.17778.stgit@srivatsabhat.in.ibm.com \
--to=srivatsa.bhat@linux.vnet.ibm.com \
--cc=akpm@linux-foundation.org \
--cc=fweisbec@gmail.com \
--cc=john.stultz@linaro.org \
--cc=laijs@cn.fujitsu.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mingo@kernel.org \
--cc=namhyung@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=nikunj@linux.vnet.ibm.com \
--cc=oleg@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=rusty@rustcorp.com.au \
--cc=sbw@mit.edu \
--cc=tglx@linutronix.de \
--cc=tj@kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=walken@google.com \
--cc=wangyun@linux.vnet.ibm.com \
--cc=xiaoguangrong@linux.vnet.ibm.com \
--cc=zhong@linux.vnet.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).