Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Andrew Morton
On Fri, 17 Apr 2015 14:37:17 -0400 Chris Metcalf wrote: > Change the default behavior of watchdog so it only runs on the > housekeeping cores when nohz_full is enabled at build and boot time. > Allow modifying the set of cores the watchdog is currently running > on with a new

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Andrew Morton
On Fri, 17 Apr 2015 14:37:17 -0400 Chris Metcalf wrote: > Change the default behavior of watchdog so it only runs on the > housekeeping cores when nohz_full is enabled at build and boot time. > Allow modifying the set of cores the watchdog is currently running > on with a new

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Don Zickus
"Andrew Morton" > >, "Andrew Jones" , "chai wen" > >, "Ulrich Obergfell" , > >"Fabian Frederick" , "Aaron Tomlin" , > >"Ben Zhang" , "Christoph Lameter" , > >"Gilad Ben-Yossef&qu

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Ulrich Obergfell
- Original Message - From: "Chris Metcalf" [...] On 04/21/2015 08:32 AM, Ulrich Obergfell wrote: >> Chris, >> >> in v9, smpboot_update_cpumask_percpu_thread() allocates 'tmp' mask >> dynamically. >> This allocation can fail and thus the function can now return an error. >> However, >>

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Ulrich Obergfell
- Original Message - From: Chris Metcalf cmetc...@ezchip.com [...] On 04/21/2015 08:32 AM, Ulrich Obergfell wrote: Chris, in v9, smpboot_update_cpumask_percpu_thread() allocates 'tmp' mask dynamically. This allocation can fail and thus the function can now return an error. However,

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Don Zickus
-...@vger.kernel.org, Thomas Gleixner t...@linutronix.de, Peter Zijlstra pet...@infradead.org Cc: Chris Metcalf cmetc...@ezchip.com Sent: Friday, April 17, 2015 8:37:17 PM Subject: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Change the default behavior of watchdog so it only runs

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Andrew Morton
On Fri, 17 Apr 2015 14:37:17 -0400 Chris Metcalf cmetc...@ezchip.com wrote: Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently running on with a new

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-29 Thread Andrew Morton
On Fri, 17 Apr 2015 14:37:17 -0400 Chris Metcalf cmetc...@ezchip.com wrote: Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently running on with a new

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Andrew Morton
On Tue, 28 Apr 2015 11:17:59 -0400 Don Zickus wrote: > cc'ing Andrew > > On Mon, Apr 27, 2015 at 04:27:16PM -0400, Chris Metcalf wrote: > > I've been out on vacation the last ten days, but picking this up > > again now. > > > > I'll wait a bit before putting out a v10, and also address Uli's

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Chris Metcalf
uot; , "Aaron Tomlin" , "Ben Zhang" , "Christoph Lameter" , "Gilad Ben-Yossef" , "Steven Rostedt" , linux-kernel@vger.kernel.org, "Jonathan Corbet" , linux-...@vger.kernel.org, "Thomas Gleixner" , "Peter Zijlstra" Cc:

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Don Zickus
cc'ing Andrew On Mon, Apr 27, 2015 at 04:27:16PM -0400, Chris Metcalf wrote: > I've been out on vacation the last ten days, but picking this up > again now. > > I'll wait a bit before putting out a v10, and also address Uli's additional > emails. Meanwhile, who is the right person to eventually

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Chris Metcalf
...@lwn.net, linux-...@vger.kernel.org, Thomas Gleixner t...@linutronix.de, Peter Zijlstra pet...@infradead.org Cc: Chris Metcalf cmetc...@ezchip.com Sent: Friday, April 17, 2015 8:37:17 PM Subject: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Change the default behavior

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Andrew Morton
On Tue, 28 Apr 2015 11:17:59 -0400 Don Zickus dzic...@redhat.com wrote: cc'ing Andrew On Mon, Apr 27, 2015 at 04:27:16PM -0400, Chris Metcalf wrote: I've been out on vacation the last ten days, but picking this up again now. I'll wait a bit before putting out a v10, and also address

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-28 Thread Don Zickus
cc'ing Andrew On Mon, Apr 27, 2015 at 04:27:16PM -0400, Chris Metcalf wrote: I've been out on vacation the last ten days, but picking this up again now. I'll wait a bit before putting out a v10, and also address Uli's additional emails. Meanwhile, who is the right person to eventually pick

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-27 Thread Chris Metcalf
I've been out on vacation the last ten days, but picking this up again now. I'll wait a bit before putting out a v10, and also address Uli's additional emails. Meanwhile, who is the right person to eventually pick up this patchset and push it up to Linus? Frederic, Don, Thomas, akpm? v9 is

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-27 Thread Chris Metcalf
I've been out on vacation the last ten days, but picking this up again now. I'll wait a bit before putting out a v10, and also address Uli's additional emails. Meanwhile, who is the right person to eventually pick up this patchset and push it up to Linus? Frederic, Don, Thomas, akpm? v9 is

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-25 Thread Ulrich Obergfell
- Original Message - From: "Don Zickus" [...] > On Tue, Apr 21, 2015 at 10:07:00AM -0400, Ulrich Obergfell wrote: >> >> Chris, >> [...] >> I think the user should only be allowed to specify a mask that is a subset of >> tick_nohz_full_mask as only those CPUs don't have a watchdog thread

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-25 Thread Ulrich Obergfell
- Original Message - From: Don Zickus dzic...@redhat.com [...] On Tue, Apr 21, 2015 at 10:07:00AM -0400, Ulrich Obergfell wrote: Chris, [...] I think the user should only be allowed to specify a mask that is a subset of tick_nohz_full_mask as only those CPUs don't have a watchdog

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Don Zickus
On Wed, Apr 22, 2015 at 07:02:31AM -0400, Ulrich Obergfell wrote: > > Chris, > > in https://lkml.org/lkml/2015/4/17/616 you stated: > > ">> +alloc_cpumask_var(_cpumask_for_smpboot, GFP_KERNEL); > > > > alloc_cpumask_var could fail? > > Good catch; if I get a failure I'll just

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Don Zickus
On Tue, Apr 21, 2015 at 10:07:00AM -0400, Ulrich Obergfell wrote: > > Chris, > > I think it would also be nice to check the plausibility of the user input. > > +int proc_watchdog_cpumask(struct ctl_table *table, int write, > + void __user *buffer, size_t *lenp, loff_t

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Ulrich Obergfell
Chris, in https://lkml.org/lkml/2015/4/17/616 you stated: ">> + alloc_cpumask_var(_cpumask_for_smpboot, GFP_KERNEL); > > alloc_cpumask_var could fail? Good catch; if I get a failure I'll just return early without trying to start the watchdog, since clearly things are too

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Don Zickus
On Tue, Apr 21, 2015 at 10:07:00AM -0400, Ulrich Obergfell wrote: Chris, I think it would also be nice to check the plausibility of the user input. +int proc_watchdog_cpumask(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos)

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Don Zickus
On Wed, Apr 22, 2015 at 07:02:31AM -0400, Ulrich Obergfell wrote: Chris, in https://lkml.org/lkml/2015/4/17/616 you stated: +alloc_cpumask_var(watchdog_cpumask_for_smpboot, GFP_KERNEL); alloc_cpumask_var could fail? Good catch; if I get a failure I'll just return

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-22 Thread Ulrich Obergfell
Chris, in https://lkml.org/lkml/2015/4/17/616 you stated: + alloc_cpumask_var(watchdog_cpumask_for_smpboot, GFP_KERNEL); alloc_cpumask_var could fail? Good catch; if I get a failure I'll just return early without trying to start the watchdog, since clearly things are too

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-21 Thread Ulrich Obergfell
Chris, I think it would also be nice to check the plausibility of the user input. +int proc_watchdog_cpumask(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ +int err; + +mutex_lock(_proc_mutex); +err =

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-21 Thread Ulrich Obergfell
x-kernel@vger.kernel.org, "Jonathan Corbet" , linux-...@vger.kernel.org, "Thomas Gleixner" , "Peter Zijlstra" Cc: "Chris Metcalf" Sent: Friday, April 17, 2015 8:37:17 PM Subject: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Ch

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-21 Thread Ulrich Obergfell
Chris, I think it would also be nice to check the plausibility of the user input. +int proc_watchdog_cpumask(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ +int err; + +mutex_lock(watchdog_proc_mutex); +

Re: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-21 Thread Ulrich Obergfell
: Friday, April 17, 2015 8:37:17 PM Subject: [PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently

[PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-17 Thread Chris Metcalf
Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently running on with a new kernel.watchdog_cpumask sysctl. If we allowed the watchdog to run on nohz_full

[PATCH v9 2/3] watchdog: add watchdog_cpumask sysctl to assist nohz

2015-04-17 Thread Chris Metcalf
Change the default behavior of watchdog so it only runs on the housekeeping cores when nohz_full is enabled at build and boot time. Allow modifying the set of cores the watchdog is currently running on with a new kernel.watchdog_cpumask sysctl. If we allowed the watchdog to run on nohz_full