From: Chris Metcalf <cmetcalf@ezchip.com>
To: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Don Zickus <dzickus@redhat.com>, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andrew Jones <drjones@redhat.com>,
chai wen <chaiw.fnst@cn.fujitsu.com>,
Fabian Frederick <fabf@skynet.be>,
Aaron Tomlin <atomlin@redhat.com>, Ben Zhang <benzh@chromium.org>,
Christoph Lameter <cl@linux.com>,
Gilad Ben-Yossef <gilad@benyossef.com>,
Steven Rostedt <rostedt@goodmis.org>,
<linux-kernel@vger.kernel.org>, Jonathan Corbet <corbet@lwn.net>,
<linux-doc@vger.kernel.org>, Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v8 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz
Date: Fri, 17 Apr 2015 11:41:16 -0400 [thread overview]
Message-ID: <5531299C.60600@ezchip.com> (raw)
In-Reply-To: <755157528.1109591.1429181212104.JavaMail.zimbra@redhat.com>
On 04/16/2015 06:46 AM, Ulrich Obergfell wrote:
> if a user changes watchdog parameters in /proc/sys/kernel, the watchdog threads
> are not stopped and restarted in all cases. Parameters can also be changed 'on
> the fly', for example like 'watchdog_thresh' in the following flow of execution:
>
> proc_watchdog_thresh
> proc_watchdog_update
> if (watchdog_enabled && watchdog_thresh)
> watchdog_enable_all_cpus
> if (!watchdog_running) {
> // watchdog threads are already running so we don't get here
> } else {
> update_watchdog_all_cpus
> for_each_online_cpu <-----------------------------.
> update_watchdog |
> watchdog_nmi_disable |
> watchdog_nmi_enable |
> } |
> |
> I think we would not want to call watchdog_nmi_enable() for each_online_ CPU,
> but rather for each CPU that has an_unparked_ watchdog thread (i.e. where the
> watchdog mechanism is actually enabled).
How about something like this? I'll fold it into v9 of the patchset.
Thanks!
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 0c5a37cdbedd..a4e1c9a2e769 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -61,6 +61,10 @@ static cpumask_var_t watchdog_cpumask_for_smpboot;
static cpumask_var_t watchdog_cpumask;
unsigned long *watchdog_cpumask_bits;
+/* Helper for online, unparked cpus. */
+#define for_each_watchdog_cpu(cpu) \
+ for_each_cpu_and((cpu), cpu_online_mask, watchdog_cpumask)
+
static int __read_mostly watchdog_running;
static u64 __read_mostly sample_period;
@@ -209,7 +213,7 @@ void touch_all_softlockup_watchdogs(void)
* do we care if a 0 races with a timestamp?
* all it means is the softlock check starts one cycle later
*/
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
per_cpu(watchdog_touch_ts, cpu) = 0;
}
@@ -616,7 +620,7 @@ void watchdog_nmi_enable_all(void)
return;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_enable(cpu);
put_online_cpus();
}
@@ -629,7 +633,7 @@ void watchdog_nmi_disable_all(void)
return;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
watchdog_nmi_disable(cpu);
put_online_cpus();
}
@@ -688,7 +692,7 @@ static void update_watchdog_all_cpus(void)
int cpu;
get_online_cpus();
- for_each_online_cpu(cpu)
+ for_each_watchdog_cpu(cpu)
update_watchdog(cpu);
put_online_cpus();
}
--
Chris Metcalf, EZChip Semiconductor
http://www.ezchip.com
next prev parent reply other threads:[~2015-04-17 15:41 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-30 18:51 [PATCH] watchdog: nohz: don't run watchdog on nohz_full cores cmetcalf
2015-03-30 19:12 ` Don Zickus
2015-03-30 19:32 ` [PATCH v2] " Chris Metcalf
2015-03-30 20:02 ` Don Zickus
2015-04-02 15:19 ` Frederic Weisbecker
2015-03-31 2:04 ` [PATCH] " Mike Galbraith
2015-03-31 6:34 ` Mike Galbraith
2015-03-31 18:32 ` Chris Metcalf
2015-03-31 7:25 ` Ingo Molnar
2015-03-31 18:30 ` Chris Metcalf
2015-04-02 13:35 ` Don Zickus
2015-04-02 13:49 ` Chris Metcalf
2015-04-02 14:15 ` Don Zickus
2015-04-02 15:38 ` Frederic Weisbecker
2015-04-02 15:42 ` Chris Metcalf
2015-04-02 16:08 ` Don Zickus
2015-04-02 16:48 ` Frederic Weisbecker
2015-04-02 17:39 ` [PATCH v3] watchdog: add watchdog_cpumask sysctl to assist nohz cmetcalf
2015-04-02 18:06 ` Peter Zijlstra
2015-04-02 18:16 ` Chris Metcalf
2015-04-02 18:33 ` Peter Zijlstra
2015-04-02 18:49 ` Chris Metcalf
2015-04-02 18:45 ` Don Zickus
2015-04-03 16:08 ` [PATCH v4 1/2] smpboot: allow excluding cpus from the smpboot threads cmetcalf
2015-04-03 16:08 ` [PATCH v4 2/2] watchdog: add watchdog_exclude sysctl to assist nohz cmetcalf
2015-04-05 16:46 ` Ulrich Obergfell
2015-04-06 19:45 ` [PATCH v5 0/2] nohz/watchdog/smp_hotplug_thread changes cmetcalf
2015-04-06 19:45 ` [PATCH v5 1/2] smpboot: allow excluding cpus from the smpboot threads cmetcalf
2015-04-08 13:28 ` Frederic Weisbecker
2015-04-08 14:06 ` Chris Metcalf
2015-04-08 17:29 ` Frederic Weisbecker
2015-04-06 19:45 ` [PATCH v5 2/2] watchdog: add watchdog_exclude sysctl to assist nohz cmetcalf
2015-04-07 15:44 ` Don Zickus
2015-04-07 15:56 ` Sasha Levin
2015-04-07 17:49 ` Chris Metcalf
2015-04-08 14:01 ` Frederic Weisbecker
2015-04-08 19:11 ` [PATCH v6 1/2] smpboot: allow excluding cpus from the smpboot threads cmetcalf
2015-04-08 19:11 ` [PATCH v6 2/2] watchdog: add watchdog_cpumask sysctl to assist nohz cmetcalf
2015-04-08 20:37 ` [PATCH v6 1/2] smpboot: allow excluding cpus from the smpboot threads Thomas Gleixner
2015-04-09 20:29 ` [PATCH] " Chris Metcalf
2015-04-10 1:58 ` Frederic Weisbecker
2015-04-10 16:33 ` Chris Metcalf
2015-04-12 19:14 ` Frederic Weisbecker
2015-04-13 16:06 ` Chris Metcalf
2015-04-13 21:54 ` Frederic Weisbecker
2015-04-14 19:37 ` [PATCH v8 1/3] " Chris Metcalf
2015-04-14 19:37 ` [PATCH v8 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Chris Metcalf
2015-04-16 10:46 ` Ulrich Obergfell
2015-04-17 15:41 ` Chris Metcalf [this message]
2015-04-22 8:20 ` Ulrich Obergfell
2015-04-28 17:52 ` Chris Metcalf
2015-04-29 8:48 ` Ulrich Obergfell
2015-04-17 1:31 ` Chai Wen
2015-04-17 16:10 ` Chris Metcalf
2015-04-14 19:37 ` [PATCH v8 3/3] procfs: treat parked tasks as sleeping for task state Chris Metcalf
2015-04-16 15:28 ` [PATCH v8 1/3] smpboot: allow excluding cpus from the smpboot threads Frederic Weisbecker
2015-04-16 15:50 ` Chris Metcalf
2015-04-16 16:48 ` Frederic Weisbecker
2015-04-17 16:17 ` Chris Metcalf
2015-04-17 18:37 ` [PATCH v9 " Chris Metcalf
2015-04-17 18:37 ` [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Chris Metcalf
2015-04-21 12:32 ` Ulrich Obergfell
2015-04-28 18:07 ` Chris Metcalf
2015-04-29 9:49 ` Ulrich Obergfell
2015-04-29 13:10 ` Don Zickus
2015-04-21 14:07 ` Ulrich Obergfell
2015-04-22 15:18 ` Don Zickus
2015-04-25 15:42 ` Ulrich Obergfell
2015-04-22 11:02 ` Ulrich Obergfell
2015-04-22 15:21 ` Don Zickus
2015-04-27 20:27 ` Chris Metcalf
2015-04-28 15:17 ` Don Zickus
2015-04-28 19:42 ` Andrew Morton
2015-04-30 19:39 ` [PATCH v10 0/3] add watchdog_cpumask to help nohz_full Chris Metcalf
2015-04-30 19:39 ` [PATCH v10 1/3] smpboot: allow excluding cpus from the smpboot threads Chris Metcalf
2015-05-01 8:53 ` Frederic Weisbecker
2015-05-01 19:57 ` Chris Metcalf
2015-05-01 21:23 ` Frederic Weisbecker
2015-05-04 22:06 ` Chris Metcalf
2015-06-03 2:34 ` Don Zickus
2015-06-04 17:25 ` Chris Metcalf
2015-05-01 20:00 ` [PATCH] smpboot: dynamically allocate the cpumask Chris Metcalf
2015-04-30 19:39 ` [PATCH v10 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Chris Metcalf
2015-04-30 20:00 ` Don Zickus
2015-04-30 20:09 ` Chris Metcalf
2015-05-01 13:46 ` Don Zickus
2015-04-30 19:39 ` [PATCH v10 3/3] procfs: treat parked tasks as sleeping for task state Chris Metcalf
2015-04-29 22:26 ` [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Andrew Morton
2015-04-29 22:26 ` Andrew Morton
2015-04-17 18:37 ` [PATCH v9 3/3] procfs: treat parked tasks as sleeping for task state Chris Metcalf
2015-04-29 22:26 ` Andrew Morton
2015-04-29 22:26 ` [PATCH v9 1/3] smpboot: allow excluding cpus from the smpboot threads Andrew Morton
2015-04-30 16:07 ` Chris Metcalf
2015-04-14 15:23 ` [PATCH] " Frederic Weisbecker
2015-04-14 15:39 ` Chris Metcalf
2015-04-14 17:57 ` Thomas Gleixner
2015-04-10 20:48 ` [PATCH v7 1/3] " Chris Metcalf
2015-04-10 20:48 ` [PATCH v7 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Chris Metcalf
2015-04-10 20:48 ` [PATCH v7 3/3] procfs: treat parked tasks as sleeping for task state Chris Metcalf
2015-04-10 21:11 ` [PATCH v7 1/3] smpboot: allow excluding cpus from the smpboot threads Andrew Morton
2015-04-13 15:48 ` Chris Metcalf
2015-04-08 19:21 ` [PATCH v5 2/2] watchdog: add watchdog_exclude sysctl to assist nohz Chris Metcalf
2015-04-08 22:31 ` Frederic Weisbecker
2015-03-31 10:17 ` [PATCH] watchdog: nohz: don't run watchdog on nohz_full cores Christoph Lameter
2015-03-31 18:39 ` Chris Metcalf
2015-04-02 14:13 ` Christoph Lameter
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=5531299C.60600@ezchip.com \
--to=cmetcalf@ezchip.com \
--cc=akpm@linux-foundation.org \
--cc=atomlin@redhat.com \
--cc=benzh@chromium.org \
--cc=chaiw.fnst@cn.fujitsu.com \
--cc=cl@linux.com \
--cc=corbet@lwn.net \
--cc=drjones@redhat.com \
--cc=dzickus@redhat.com \
--cc=fabf@skynet.be \
--cc=fweisbec@gmail.com \
--cc=gilad@benyossef.com \
--cc=linux-doc@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
--cc=uobergfe@redhat.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).