From: Andrew Morton <akpm@linux-foundation.org>
To: "Pan, Zhenjie" <zhenjie.pan@intel.com>
Cc: "a.p.zijlstra@chello.nl" <a.p.zijlstra@chello.nl>,
"paulus@samba.org" <paulus@samba.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"acme@ghostprotocols.net" <acme@ghostprotocols.net>,
"dzickus@redhat.com" <dzickus@redhat.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Liu, Chuansheng" <chuansheng.liu@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] NMI: fix NMI period is not correct when cpu frequency changes issue.
Date: Mon, 15 Apr 2013 21:29:14 -0700 [thread overview]
Message-ID: <20130415212914.936f903a.akpm@linux-foundation.org> (raw)
In-Reply-To: <F98D4B5C3D86834DB612ABF854C98B7FB5D662@SHSMSX101.ccr.corp.intel.com>
On Tue, 16 Apr 2013 03:45:15 +0000 "Pan, Zhenjie" <zhenjie.pan@intel.com> wrote:
> > Overall the patch looks desirable, but it increases the kernel size by several
> > hundred bytes when CONFIG_CPU_FREQ=n. It should produce no code in
> > this case! Take a look at the magic in register_hotcpu_notifier(), the way in
> > which it causes all the code to be removed by the compiler in the
> > CONFIG_HOTPLUG_CPU=n case. That trick can be used here.
>
> I have checked if CONFIG_CPU_FREQ=n, cpufreq_register_notifier() will be a blank function.
> So I think it will not increases the kernel size.
I tested it. The patch adds ~350 bytes of dead code.
This is partly an infrastructural problem: unlike
register_hotcpu_notifier(), the cpufreq notifier code lacks the
infrastructure with which we can prevent this problem.
next prev parent reply other threads:[~2013-04-16 4:29 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-01 3:47 [PATCH] NMI: fix NMI period is not correct when cpu frequency changes issue Pan, Zhenjie
2013-04-03 18:00 ` Don Zickus
2013-04-16 3:26 ` Pan, Zhenjie
2013-04-15 23:30 ` Andrew Morton
2013-04-16 3:45 ` Pan, Zhenjie
2013-04-16 4:29 ` Andrew Morton [this message]
2013-04-18 11:32 ` Peter Zijlstra
2013-07-24 17:48 ` Frederic Weisbecker
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