From: "Liu, Jinsong" <jinsong.liu@intel.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
"lenb@kernel.org" <lenb@kernel.org>
Subject: RE: [PATCH V1 1/2] Xen acpi memory hotplug driver
Date: Thu, 6 Dec 2012 04:27:36 +0000 [thread overview]
Message-ID: <DE8DF0795D48FD4CA783C40EC82923353A2366@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <20121205174307.GC16072@phenom.dumpdata.com>
>>>> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
>>>> index 126d8ce..abd0396 100644
>>>> --- a/drivers/xen/Kconfig
>>>> +++ b/drivers/xen/Kconfig
>>>> @@ -206,4 +206,15 @@ config XEN_MCE_LOG
>>>> Allow kernel fetching MCE error from Xen platform and
>>>> converting it into Linux mcelog format for mcelog tools
>>>>
>>>> +config XEN_ACPI_MEMORY_HOTPLUG
>>>> + bool "Xen ACPI memory hotplug"
>>>
>>> There should be a way to make this a module.
>>
>> I have some concerns to make it a module:
>> 1. xen and native memhotplug driver both work as module, while we
>> need early load xen driver.
>> 2. if possible, a xen stub driver may solve load sequence issue, but
>> it may involve other issues * if xen driver load then unload,
>> native driver may have chance to load successfully;
>
> The stub driver would still "occupy" the ACPI bus for the memory
> hotplug PnP, so I think this would not be a problem.
>
I'm not quite clear your mean here, do you mean it has
1. xen_stub driver + xen_memhoplug driver, then xen_strub driver unload and entirely replaced by xen_memhotplug driver, or
2. xen_stub driver (w/ stub ops) + xen_memhotplug ops (not driver), then xen_stub driver keep occupying but its stub ops later replaced by xen_memhotplug ops?
If in way #1, it has risk that native driver may load (if xen driver unload).
If in way #2, xen_memhotplug ops lose the chance to probe/add/bind existed memory devices (since it's done when driver registerred).
>> * if xen driver load --> unload --> load again, then it will lose
>> hotplug notification during unload period;
>
> Sure. But I think we can do it with this driver? After all the
> function of
> it is to just tell the firmware to turn on/off sockets - and if we
> miss
> one notification we won't take advantage of the power savings - but we
> can do that later on.
>
Not only inform firmware.
Hotplug notify callback will invoke acpi_bus_add -> ... -> implicitly invoke drv->ops.add method to add the hotadded memory device.
>
>> * if xen driver load --> unload --> load again, then it will
>> re-add all memory devices, but the handle for 'booting memory
>> device' and 'hotplug memory device' are different while we have no
>> way to distinguish these 2 kind of devices.
>
> Wouldn't the stub driver hold onto that?
>
Same question as comment #1. Do you mean it has a xen_stub driver (w/ stub ops) and a xen_memhotplug ops?
>>
>> IMHO I think to make xen hotplug logic as module may involves
>> unexpected result. Is there any obvious advantages of doing so?
>> after all we have provided config choice to user. Thoughts?
>
> Yes, it becomes a module - which is what we want.
>
What I meant here is, module will bring some unexpected issues for xen hotplug.
We can provide user 'bool' config choice, let them decide to build-in or not, but not 'tristate' choice.
Thanks
Jinsong
next prev parent reply other threads:[~2012-12-06 4:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-21 11:45 [PATCH V1 1/2] Xen acpi memory hotplug driver Liu, Jinsong
2012-11-28 19:26 ` Konrad Rzeszutek Wilk
2012-11-30 3:08 ` Liu, Jinsong
2012-12-05 17:43 ` Konrad Rzeszutek Wilk
2012-12-06 4:27 ` Liu, Jinsong [this message]
2012-12-07 14:05 ` Konrad Rzeszutek Wilk
2012-12-12 17:53 ` Liu, Jinsong
2012-12-14 13:05 ` Liu, Jinsong
2012-12-18 13:15 ` Liu, Jinsong
2012-12-18 15:47 ` Konrad Rzeszutek Wilk
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=DE8DF0795D48FD4CA783C40EC82923353A2366@SHSMSX101.ccr.corp.intel.com \
--to=jinsong.liu@intel.com \
--cc=konrad.wilk@oracle.com \
--cc=lenb@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=xen-devel@lists.xensource.com \
/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;
as well as URLs for NNTP newsgroup(s).