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From: Petr Mladek <pmladek@suse.com>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jiri Kosina <jkosina@suse.cz>, Borislav Petkov <bp@suse.de>,
	Michal Hocko <mhocko@suse.cz>,
	linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 04/22] kthread: Add create_kthread_worker*()
Date: Tue, 16 Feb 2016 16:44:43 +0100	[thread overview]
Message-ID: <20160216154443.GW12548@pathway.suse.cz> (raw)
In-Reply-To: <20160125185339.GB3628@mtj.duckdns.org>

On Mon 2016-01-25 13:53:39, Tejun Heo wrote:
> On Mon, Jan 25, 2016 at 04:44:53PM +0100, Petr Mladek wrote:
> > +struct kthread_worker *
> > +create_kthread_worker_on_cpu(int cpu, const char namefmt[])
> > +{
> > +	if (cpu < 0 || cpu > num_possible_cpus())
> > +		return ERR_PTR(-EINVAL);
> 
> Comparing cpu ID to num_possible_cpus() doesn't make any sense.  It
> should either be testing against cpu_possible_mask or testing against
> nr_cpu_ids.  Does this test need to be in this function at all?

I wanted to be sure. The cpu number is later passed to
cpu_to_node(cpu) in kthread_create_on_cpu().

I am going to replace this with a check against nr_cpu_ids in
kthread_create_on_cpu() which makes more sense.

I might be too paranoid. But this is slow path. People
do mistakes...

Thanks,
Petr

WARNING: multiple messages have this Message-ID (diff)
From: Petr Mladek <pmladek@suse.com>
To: Tejun Heo <tj@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>, Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jiri Kosina <jkosina@suse.cz>, Borislav Petkov <bp@suse.de>,
	Michal Hocko <mhocko@suse.cz>,
	linux-mm@kvack.org, Vlastimil Babka <vbabka@suse.cz>,
	linux-api@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 04/22] kthread: Add create_kthread_worker*()
Date: Tue, 16 Feb 2016 16:44:43 +0100	[thread overview]
Message-ID: <20160216154443.GW12548@pathway.suse.cz> (raw)
In-Reply-To: <20160125185339.GB3628@mtj.duckdns.org>

On Mon 2016-01-25 13:53:39, Tejun Heo wrote:
> On Mon, Jan 25, 2016 at 04:44:53PM +0100, Petr Mladek wrote:
> > +struct kthread_worker *
> > +create_kthread_worker_on_cpu(int cpu, const char namefmt[])
> > +{
> > +	if (cpu < 0 || cpu > num_possible_cpus())
> > +		return ERR_PTR(-EINVAL);
> 
> Comparing cpu ID to num_possible_cpus() doesn't make any sense.  It
> should either be testing against cpu_possible_mask or testing against
> nr_cpu_ids.  Does this test need to be in this function at all?

I wanted to be sure. The cpu number is later passed to
cpu_to_node(cpu) in kthread_create_on_cpu().

I am going to replace this with a check against nr_cpu_ids in
kthread_create_on_cpu() which makes more sense.

I might be too paranoid. But this is slow path. People
do mistakes...

Thanks,
Petr

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  reply	other threads:[~2016-02-16 15:44 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-25 15:44 [PATCH v4 00/22] kthread: Use kthread worker API more widely Petr Mladek
2016-01-25 15:44 ` Petr Mladek
2016-01-25 15:44 ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 01/22] timer: Allow to check when the timer callback has not finished yet Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 18:44   ` Tejun Heo
2016-01-25 18:44     ` Tejun Heo
2016-01-25 15:44 ` [PATCH v4 02/22] kthread/smpboot: Do not park in kthread_create_on_cpu() Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 03/22] kthread: Allow to call __kthread_create_on_node() with va_list args Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 04/22] kthread: Add create_kthread_worker*() Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 18:53   ` Tejun Heo
2016-01-25 18:53     ` Tejun Heo
2016-02-16 15:44     ` Petr Mladek [this message]
2016-02-16 15:44       ` Petr Mladek
2016-02-16 16:08       ` Tejun Heo
2016-02-16 16:08         ` Tejun Heo
2016-02-16 16:08         ` Tejun Heo
2016-02-16 16:10       ` Petr Mladek
2016-02-16 16:10         ` Petr Mladek
2016-02-16 16:10         ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 05/22] kthread: Add drain_kthread_worker() Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 06/22] kthread: Add destroy_kthread_worker() Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 07/22] kthread: Detect when a kthread work is used by more workers Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 18:57   ` Tejun Heo
2016-01-25 18:57     ` Tejun Heo
2016-01-25 18:57     ` Tejun Heo
2016-02-16 16:38     ` Petr Mladek
2016-02-16 16:38       ` Petr Mladek
2016-02-16 16:38       ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 08/22] kthread: Initial support for delayed kthread work Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 19:04   ` Tejun Heo
2016-01-25 19:04     ` Tejun Heo
2016-01-25 19:04     ` Tejun Heo
2016-01-25 15:44 ` [PATCH v4 09/22] kthread: Allow to cancel " Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 19:17   ` Tejun Heo
2016-01-25 19:17     ` Tejun Heo
2016-02-19 16:22     ` Petr Mladek
2016-02-19 16:22       ` Petr Mladek
2016-01-25 15:44 ` [PATCH v4 10/22] kthread: Allow to modify delayed " Petr Mladek
2016-01-25 15:44   ` Petr Mladek
2016-01-25 19:19   ` Tejun Heo
2016-01-25 19:19     ` Tejun Heo
2016-01-25 15:45 ` [PATCH v4 11/22] kthread: Better support freezable kthread workers Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 19:21   ` Tejun Heo
2016-01-25 19:21     ` Tejun Heo
2016-01-25 15:45 ` [PATCH v4 12/22] kthread: Use try_lock_kthread_work() in flush_kthread_work() Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 13/22] mm/huge_page: Convert khugepaged() into kthread worker API Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 14/22] ring_buffer: Convert benchmark kthreads " Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 15/22] hung_task: Convert hungtaskd " Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 16/22] kmemleak: Convert kmemleak kthread " Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 17/22] ipmi: Convert kipmi " Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 18/22] IB/fmr_pool: Convert the cleanup thread " Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 19/22] memstick/r592: Better synchronize debug messages in r592_io kthread Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 20/22] memstick/r592: convert r592_io kthread into kthread worker API Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 15:45 ` [PATCH v4 21/22] thermal/intel_powerclamp: Remove duplicated code that starts the kthread Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 16:23   ` Jacob Pan
2016-01-25 16:23     ` Jacob Pan
2016-01-25 15:45 ` [PATCH v4 22/22] thermal/intel_powerclamp: Convert the kthread to kthread worker API Petr Mladek
2016-01-25 15:45   ` Petr Mladek
2016-01-25 16:28   ` Jacob Pan
2016-01-25 16:28     ` Jacob Pan

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