From: Toshi Kani <toshi.kani@hp.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-s390@vger.kernel.org, jiang.liu@huawei.com,
wency@cn.fujitsu.com, linux-mm@kvack.org, yinghai@kernel.org,
linux-kernel@vger.kernel.org, rjw@sisk.pl,
linux-acpi@vger.kernel.org, isimatu.yasuaki@jp.fujitsu.com,
srivatsa.bhat@linux.vnet.ibm.com, guohanjun@huawei.com,
bhelgaas@google.com, akpm@linux-foundation.org,
linuxppc-dev@lists.ozlabs.org, lenb@kernel.org
Subject: Re: [RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework
Date: Wed, 30 Jan 2013 19:57:45 -0700 [thread overview]
Message-ID: <1359601065.15120.156.camel@misato.fc.hp.com> (raw)
In-Reply-To: <20130130045830.GH30002@kroah.com>
On Tue, 2013-01-29 at 23:58 -0500, Greg KH wrote:
> On Thu, Jan 10, 2013 at 04:40:19PM -0700, Toshi Kani wrote:
> > +/*
> > + * Hot-plug device information
> > + */
>
> Again, stop it with the "generic" hotplug term here, and everywhere
> else. You are doing a very _specific_ type of hotplug devices, so spell
> it out. We've worked hard to hotplug _everything_ in Linux, you are
> going to confuse a lot of people with this type of terms.
Agreed. I will clarify in all places.
> > +union shp_dev_info {
> > + struct shp_cpu {
> > + u32 cpu_id;
> > + } cpu;
>
> What is this? Why not point to the system device for the cpu?
This info is used to on-line a new CPU and create its system/cpu device.
In other word, a system/cpu device is created as a result of CPU
hotplug.
> > + struct shp_memory {
> > + int node;
> > + u64 start_addr;
> > + u64 length;
> > + } mem;
>
> Same here, why not point to the system device?
Same as above.
> > + struct shp_hostbridge {
> > + } hb;
> > +
> > + struct shp_node {
> > + } node;
>
> What happened here with these? Empty structures? Huh?
They are place holders for now. PCI bridge hot-plug and node hot-plug
are still very much work in progress, so I have not integrated them into
this framework yet.
> > +};
> > +
> > +struct shp_device {
> > + struct list_head list;
> > + struct device *device;
>
> No, make it a "real" device, embed the device into it.
This device pointer is used to send KOBJ_ONLINE/OFFLINE event during CPU
online/offline operation in order to maintain the current behavior. CPU
online/offline operation only changes the state of CPU, so its
system/cpu device continues to be present before and after an operation.
(Whereas, CPU hot-add/delete operation creates or removes a system/cpu
device.) So, this "*device" needs to be a pointer to reference an
existing device that is to be on-lined/off-lined.
> But, again, I'm going to ask why you aren't using the existing cpu /
> memory / bridge / node devices that we have in the kernel. Please use
> them, or give me a _really_ good reason why they will not work.
We cannot use the existing system devices or ACPI devices here. During
hot-plug, ACPI handler sets this shp_device info, so that cpu and memory
handlers (drivers/cpu.c and mm/memory_hotplug.c) can obtain their target
device information in a platform-neutral way. During hot-add, we first
creates an ACPI device node (i.e. device under /sys/bus/acpi/devices),
but platform-neutral modules cannot use them as they are ACPI-specific.
Also, its system device (i.e. device under /sys/devices/system) has not
been created until the hot-add operation completes.
> > + enum shp_class class;
> > + union shp_dev_info info;
> > +};
> > +
> > +/*
> > + * Hot-plug request
> > + */
> > +struct shp_request {
> > + /* common info */
> > + enum shp_operation operation; /* operation */
> > +
> > + /* hot-plug event info: only valid for hot-plug operations */
> > + void *handle; /* FW handle */
> > + u32 event; /* FW event */
>
> What is this?
The shp_request describes a hotplug or online/offline operation that is
requested. In case of hot-plug request, the "*handle" describes a
target device (which is an ACPI device object) and the "event" describes
a type of request, such as hot-add or hot-delete.
Thanks,
-Toshi
next prev parent reply other threads:[~2013-01-31 3:07 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-10 23:40 [RFC PATCH v2 00/12] System device hot-plug framework Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework Toshi Kani
2013-01-11 21:23 ` Rafael J. Wysocki
2013-01-14 15:33 ` Toshi Kani
2013-01-14 18:48 ` Rafael J. Wysocki
2013-01-14 19:02 ` Toshi Kani
2013-01-30 4:48 ` Greg KH
2013-01-31 1:15 ` Toshi Kani
2013-01-31 5:24 ` Greg KH
2013-01-31 14:42 ` Toshi Kani
2013-01-30 4:53 ` Greg KH
2013-01-31 1:46 ` Toshi Kani
2013-01-30 4:58 ` Greg KH
2013-01-31 2:57 ` Toshi Kani [this message]
2013-01-31 20:54 ` Rafael J. Wysocki
2013-02-01 1:32 ` Toshi Kani
2013-02-01 7:30 ` Greg KH
2013-02-01 20:40 ` Toshi Kani
2013-02-01 22:21 ` Rafael J. Wysocki
2013-02-01 23:12 ` Toshi Kani
2013-02-02 15:01 ` Greg KH
2013-02-04 0:28 ` Toshi Kani
2013-02-04 12:46 ` Greg KH
2013-02-04 16:46 ` Toshi Kani
2013-02-04 19:45 ` Rafael J. Wysocki
2013-02-04 20:59 ` Toshi Kani
2013-02-04 23:23 ` Rafael J. Wysocki
2013-02-04 23:33 ` Toshi Kani
2013-02-01 7:23 ` Greg KH
2013-02-01 22:12 ` Rafael J. Wysocki
2013-02-02 14:58 ` Greg KH
2013-02-02 20:15 ` Rafael J. Wysocki
2013-02-02 22:18 ` [PATCH?] Move ACPI device nodes under /sys/firmware/acpi (was: Re: [RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework) Rafael J. Wysocki
2013-02-04 1:24 ` Greg KH
2013-02-04 12:34 ` Rafael J. Wysocki
2013-02-03 20:44 ` [RFC PATCH v2 01/12] Add sys_hotplug.h for system device hotplug framework Rafael J. Wysocki
2013-02-04 12:48 ` Greg KH
2013-02-04 14:21 ` Rafael J. Wysocki
2013-02-04 14:33 ` Greg KH
2013-02-04 20:07 ` Rafael J. Wysocki
2013-02-04 22:13 ` Toshi Kani
2013-02-04 23:52 ` Rafael J. Wysocki
2013-02-05 0:04 ` Greg KH
2013-02-05 1:02 ` Rafael J. Wysocki
2013-02-05 11:11 ` Rafael J. Wysocki
2013-02-05 18:39 ` Greg KH
2013-02-05 21:13 ` Rafael J. Wysocki
2013-02-05 0:55 ` Toshi Kani
2013-02-04 16:19 ` Toshi Kani
2013-02-04 19:43 ` Rafael J. Wysocki
2013-02-04 1:23 ` Greg KH
2013-02-04 13:41 ` Rafael J. Wysocki
2013-02-04 16:02 ` Toshi Kani
2013-02-04 19:48 ` Rafael J. Wysocki
2013-02-04 19:46 ` Toshi Kani
2013-02-04 20:12 ` Rafael J. Wysocki
2013-02-04 20:34 ` Toshi Kani
2013-02-04 23:19 ` Rafael J. Wysocki
2013-01-10 23:40 ` [RFC PATCH v2 02/12] ACPI: " Toshi Kani
2013-01-11 21:25 ` Rafael J. Wysocki
2013-01-14 15:53 ` Toshi Kani
2013-01-14 18:47 ` Rafael J. Wysocki
2013-01-14 18:42 ` Toshi Kani
2013-01-14 19:07 ` Rafael J. Wysocki
2013-01-14 19:21 ` Toshi Kani
2013-01-30 4:51 ` Greg KH
2013-01-31 1:38 ` Toshi Kani
2013-01-14 19:21 ` Greg KH
2013-01-14 19:29 ` Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 03/12] drivers/base: Add " Toshi Kani
2013-01-30 4:54 ` Greg KH
2013-01-31 1:48 ` Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 04/12] cpu: Add cpu hotplug handlers Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 05/12] mm: Add memory " Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 06/12] ACPI: Add ACPI bus " Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 07/12] ACPI: Add ACPI resource hotplug handler Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 08/12] ACPI: Update processor driver for hotplug framework Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 09/12] ACPI: Update memory " Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 10/12] ACPI: Update container " Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 11/12] cpu: Update sysfs cpu/online " Toshi Kani
2013-01-10 23:40 ` [RFC PATCH v2 12/12] ACPI: Update sysfs eject " Toshi Kani
2013-01-17 0:50 ` [RFC PATCH v2 00/12] System device hot-plug framework Rafael J. Wysocki
2013-01-17 17:59 ` Toshi Kani
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