public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Trinabh Gupta <trinabh@linux.vnet.ibm.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Len Brown <lenb@kernel.org>, Len Brown <len.brown@intel.com>,
	linux-pm@lists.linux-foundation.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, Jiri Kosina <jkosina@suse.cz>
Subject: Re: [linux-pm] [PATCH 04/18] x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it
Date: Sat, 02 Apr 2011 17:51:55 +0530	[thread overview]
Message-ID: <4D9714E3.8010302@linux.vnet.ibm.com> (raw)
In-Reply-To: <20110402122857.5fb7d2b7@lxorguk.ukuu.org.uk>



On 04/02/2011 04:58 PM, Alan Cox wrote:
> On Sat, 02 Apr 2011 02:22:46 -0400
> Len Brown<lenb@kernel.org>  wrote:
>
>> From: Len Brown<len.brown@intel.com>
>>
>> In the long run, we don't want default_idle() or (pm_idle)() to
>> be exported outside of process.c.  Start by not exporting them
>> to modules, unless the APM build demands it.
>
> Pointless added complexity. Why are you so determined to minimise this -
> it makes no odds to anyone.

Hi Alan,

I am not sure if I have understood you correctly but
I think one problem is that modules such as APM
save the value of pm_idle pointer, set it and restore it back.

At module init:

original_pm_idle = pm_idle;
pm_idle  = apm_cpu_idle;

At module exit:

pm_idle = original_pm_idle;

There is no guarantee that the pointer stored
is still valid. I think people have problem with such
usage; see http://lkml.org/lkml/2009/8/28/50

Thanks,
-Trinabh

  reply	other threads:[~2011-04-02 12:22 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-24  7:08 [PATCH 0/5] x86 idle cruft removal Len Brown
2011-03-24  7:08 ` [PATCH 1/5] x86 idle: remove "no-hlt" cmdline param Len Brown
2011-03-24  7:08   ` [PATCH 2/5] x86 idle: remove NOP cpuinfo_x86.hlt_works_ok flag Len Brown
2011-03-24  7:08   ` [PATCH 3/5] x86 idle: remove NOP halt_works() Len Brown
2011-03-24  7:08   ` [PATCH 4/5] x86 idle floppy: delete disable_hlt()/enable_hlt() Len Brown
2011-03-24 15:58     ` Andi Kleen
2011-03-24  7:08   ` [PATCH 5/5] x86 idle: remove NOP hlt_use_halt() Len Brown
2011-03-25 19:02     ` [linux-pm] " Vaidyanathan Srinivasan
2011-03-31  6:03 ` [PATCH 0/9] x86 idle cruft removal - v2 Len Brown
2011-03-31  6:03   ` [PATCH 1/9] x86 idle: remove "no-hlt" cmdline param Len Brown
2011-03-31  6:03     ` [PATCH 2/9] x86 idle: remove NOP cpuinfo_x86.hlt_works_ok flag Len Brown
2011-03-31  6:12       ` Ingo Molnar
2011-03-31  7:02         ` Len Brown
2011-03-31  8:18           ` Ingo Molnar
2011-03-31  9:23             ` Alan Cox
2011-03-31  9:27               ` Ingo Molnar
2011-03-31  9:33                 ` Alan Cox
2011-03-31  9:35                   ` Ingo Molnar
2011-03-31 14:19                     ` H. Peter Anvin
2011-03-31 14:41                       ` Alan Cox
2011-03-31 15:09                         ` H. Peter Anvin
2011-03-31 18:07             ` Len Brown
2011-03-31 18:28               ` H. Peter Anvin
2011-03-31  6:03     ` [PATCH 3/9] x86 idle: remove NOP halt_works() Len Brown
2011-03-31  6:03     ` [PATCH 4/9] x86 idle floppy: delete disable_hlt()/enable_hlt() Len Brown
2011-03-31  6:03     ` [PATCH 5/9] x86 idle: remove NOP hlt_use_halt() Len Brown
2011-03-31  6:03     ` [PATCH 6/9] x86 idle APM: delete apm_cpu_idle(), and its use of (pm_idle)() Len Brown
2011-03-31  6:03     ` [PATCH 7/9] x86 idle: do not EXPORT_SYMBOL pm_idle and default_idle Len Brown
2011-03-31  6:03     ` [PATCH 8/9] x86 idle: move mwait_idle_with_hints() to where it is used Len Brown
2011-03-31  6:03     ` [PATCH 9/9] x86 idle: delete mwait_idle() Len Brown
2011-04-01 11:02       ` Andreas Herrmann
2011-03-31  6:39   ` [linux-pm] [PATCH 0/9] x86 idle cruft removal - v2 Trinabh Gupta
2011-03-31  7:21     ` Len Brown
2011-03-31  9:45   ` Alan Cox
2011-03-31 10:28     ` Ingo Molnar
2011-04-01  4:24   ` Len Brown
2011-04-01  9:38     ` [linux-pm] " Trinabh Gupta
2011-04-01 18:33       ` Len Brown
2011-04-02  6:22     ` idle cleanup - v3 Len Brown
2011-04-02  6:22       ` [PATCH 01/18] cpuidle: menu: fixed wrapping timers at 4.294 seconds Len Brown
2011-04-02  6:22         ` [PATCH 02/18] x86 idle floppy: deprecate disable_hlt() Len Brown
2011-04-02  6:22         ` [PATCH 03/18] x86 idle APM: deprecate CONFIG_APM_CPU_IDLE Len Brown
2011-04-02 11:28           ` Alan Cox
2011-04-02 18:28             ` Len Brown
2011-04-02 19:44               ` Alan Cox
2011-04-08  6:22               ` Pavel Machek
2011-04-02  6:22         ` [PATCH 04/18] x86 idle: EXPORT_SYMBOL(default_idle, pm_idle) only when APM demands it Len Brown
2011-04-02 11:28           ` Alan Cox
2011-04-02 12:21             ` Trinabh Gupta [this message]
2011-04-02  6:22         ` [PATCH 05/18] x86 idle: deprecate "no-hlt" cmdline param Len Brown
2011-04-02  6:22         ` [PATCH 06/18] x86 idle: deprecate mwait_idle() and "idle=mwait" " Len Brown
2011-04-02  6:22         ` [PATCH 07/18] x86 idle: clarify AMD erratum 400 workaround Len Brown
2011-04-02  8:23           ` Borislav Petkov
2011-04-02 19:19             ` Len Brown
2011-04-02 19:22               ` [PATCH 07/18] x86 idle: clarify AMD erratum 400 workaround -v2 Len Brown
2011-04-03  9:00                 ` Borislav Petkov
2011-04-02  6:22         ` [PATCH 08/18] cpuidle: create bootparam "cpuidle.off=1" Len Brown
2011-07-15 11:27           ` [linux-pm] " Deepthi Dharwar
2011-04-02  6:22         ` [PATCH 09/18] cpuidle: replace xen access to x86 pm_idle and default_idle Len Brown
2011-04-04 15:33           ` [Xen-devel] " Konrad Rzeszutek Wilk
2011-04-02  6:22         ` [PATCH 10/18] x86 idle: move mwait_idle_with_hints() to where it is used Len Brown
2011-04-02  6:22         ` [PATCH 11/18] cpuidle: stop using pm_idle Len Brown
2011-04-25 10:41           ` [linux-pm] " Trinabh Gupta
2011-04-02  6:22         ` [PATCH 12/18] 2.6.40: x86 idle: remove deprecated "no-hlt" cmdline param Len Brown
2011-04-02  6:22         ` [PATCH 13/18] 2.6.40: x86 idle: remove deprecated "hlt_bug: no" in 32-bit /proc/cpuinfo Len Brown
2011-04-02  6:22         ` [PATCH 14/18] 2.6.40: x86 idle floppy: remove deprecated disable_hlt()/enable_hlt() Len Brown
2011-04-02  6:22         ` [PATCH 15/18] 2.6.40: x86 idle: remove deprecated hlt_use_halt() Len Brown
2011-04-02  6:22         ` [PATCH 16/18] 2.6.40: x86 idle APM: remove deprecated apm_cpu_idle() Len Brown
2011-04-02 11:40           ` Alan Cox
2011-04-02 19:44             ` Len Brown
2011-04-02 21:00               ` Alan Cox
2011-04-03  2:48                 ` [linux-pm] " Trinabh Gupta
2011-04-04 10:05                   ` Alan Cox
2011-04-02  6:22         ` [PATCH 17/18] 2.6.40: x86 idle: do not export default_idle() and (pm_idle)() Len Brown
2011-04-02  6:23         ` [PATCH 18/18] 2.6.40: x86 idle: remove deprecated mwait_idle() Len Brown

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=4D9714E3.8010302@linux.vnet.ibm.com \
    --to=trinabh@linux.vnet.ibm.com \
    --cc=alan@lxorguk.ukuu.org.uk \
    --cc=jkosina@suse.cz \
    --cc=len.brown@intel.com \
    --cc=lenb@kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-pm@lists.linux-foundation.org \
    --cc=x86@kernel.org \
    /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