From: Nathan Fontenot <nfont@austin•ibm.com>
To: Benjamin Herrenschmidt <benh@kernel•crashing.org>
Cc: linuxppc-dev@ozlabs•org, Andreas Schwab <schwab@linux-m68k•org>
Subject: Re: [PATCH] Make cpu hotplug driver lock part of ppc_md
Date: Tue, 12 Jan 2010 13:34:39 -0600 [thread overview]
Message-ID: <4B4CCECF.3040800@austin.ibm.com> (raw)
In-Reply-To: <1263262996.724.176.camel@pasglop>
Benjamin Herrenschmidt wrote:
>> The intention of the cpu_hotplug_driver_locks to add additional serialization
>> during cpu hotplug operations. For pseries this is used during DLPAR of cpu
>> operations so that cpu hotplug actions cannot be initiated whiloe a DLPAR
>> operation is in flight. For example, during DLPAR add we take the lock while
>> acquiring the cpu from firmware and updating the device tree with the new
>> cpu information, after which we hotplug add the cpu to the system.
>>
>> There is nothing harmless about taking the lock on all platforms, I was just
>> trying to avoid taking the lock if the additional serialization is not needed.
>>
>>> If so, you could just make the mutex available to all powerpc code, and
>>> rename it, and then we wouldn't need all this jiggery pokery just to
>>> take & release a lock.
>> I can make the lock available to all powerpc code and not go through the
>> ppc_md struct, it makes no difference to me personally. Of course this would
>> make all that fun pokery jiggery go away :)
>
> Yeah, Michael is right, just make it global to powerpc, it should make
> things simpler.
Sounds good, I'll get a patch out to do this.
-Nathan
prev parent reply other threads:[~2010-01-12 19:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-22 14:45 [PATCH] Make cpu hotplug driver lock part of ppc_md Nathan Fontenot
2009-12-22 22:29 ` Michael Ellerman
2009-12-23 14:48 ` Nathan Fontenot
2009-12-23 22:29 ` Michael Ellerman
2010-01-12 2:23 ` Benjamin Herrenschmidt
2010-01-12 19:34 ` Nathan Fontenot [this message]
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=4B4CCECF.3040800@austin.ibm.com \
--to=nfont@austin$(echo .)ibm.com \
--cc=benh@kernel$(echo .)crashing.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=schwab@linux-m68k$(echo .)org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
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