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Date: Wed, 20 Feb 2013 12:35:48 +0900
From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
To: Vasilis Liaskovitis <vasilis.liaskovitis@...fitbricks.com>
CC: "Rafael J. Wysocki" <rjw@...k.pl>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Bjorn Helgaas <bhelgaas@...gle.com>,
LKML <linux-kernel@...r.kernel.org>,
Yinghai Lu <yinghai@...nel.org>,
Toshi Kani <toshi.kani@...com>, Jiang Liu <liuj97@...il.com>
Subject: Re: [PATCH 7/7] ACPI / scan: Make memory hotplug driver use struct
acpi_scan_handler
Hi Vasilis,
2013/02/20 3:11, Vasilis Liaskovitis wrote:
> Hi,
>
> On Sun, Feb 17, 2013 at 04:27:18PM +0100, Rafael J. Wysocki wrote:
>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>
>> Make the ACPI memory hotplug driver use struct acpi_scan_handler
>> for representing the object used to set up ACPI memory hotplug
>> functionality and to remove hotplug memory ranges and data
>> structures used by the driver before unregistering ACPI device
>> nodes representing memory. Register the new struct acpi_scan_handler
>> object with the help of acpi_scan_add_handler_with_hotplug() to allow
>> user space to manipulate the attributes of the memory hotplug
>> profile.
>
> Let's consider an example where we want acpi memory device ejection to be safely
> handled by userspace. We do the following:
>
> echo 0 > /sys/firmware/acpi/hotplug/memory/autoeject
> echo 1 > /sys/firmware/acpi/hotplug/memory/uevents
>
> We succesfully hotplug acpi device:
> /sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00
> and its corresponding memblocks /sys/devices/system/memory/memoryXX are
> also successfully onlined.
>
> On an eject request, since uevents == 1, the kernel will emit KOBJ_OFFLINE for:
> /sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00
>
> Can userspace know which memblocks in /sys/devices/system/memory/memoryXX/
> correspond to the acpi device /sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:00 ?
> This will be needed so that userspace tries to offline the memblocks (and only
> if successful, issue the eject operation on the acpi device). As far as I see,
> we don't create any sysfs links or files for this scenario - can userspace get
> this info somehow?
>
> /sys/devices/system/memory/memoryXX/phys_device needs to be properly implemented
> for this to work I think, see Documentation/ABI/testing/sysfs-memory
>
> The following test patch works toward that direction. Let me know if it's of
> interest or if there are better ideas /comments.
How about use ../PNP0C80:00/physical_node/resources file?
In my system, the file shows following information.
$ cat /sys/bus/acpi/devices/PNP0C80\:00/physical_node/resources
state = active
mem 0x0-0x80000000
mem 0x100000000-0x800000000
It means PNP0C80:00's memory ranges are "0x0-0x7fffffff" and
"0x100000000-0x7ffffffff". In x86 architecture, memory section size is
128MiB. So, if these memory range is divided by 128MiB, you can
calculate memory section number as follow:
0x0-0x7fffffff => 0x0-0x10
0x100000000-0x7ffffffff => 0x20-0xff
But there is one problem. The problem is that resources file of added memory
is not created. If the problem is fixed, I think you can use the way.
>
> From: Vasilis Liaskovitis <vasilis.liaskovitis@...fitbricks.com>
> Date: Tue, 19 Feb 2013 18:36:25 +0100
> Subject: [RFC PATCH] acpi / memory-hotplug: implement phys_device
>
> In order for userspace to know which memblocks in:
> /sys/devices/system/memory/memoryXX correspond to which acpi memory devices in:
> /sys/devices/LNXSYSTM:00/LNXSYSBUS:00/PNP0C80:YY,
> /sys/devices/system/memory/memoryXX/phys_device should return a name (or index
> YY) of the memory device each memblock XX belongs to.
>
> WIth this patch, the acpi mem_hotplug driver keeps a global list of acpi memory
> devices (inserted in hotplug_order). The base memory driver checks against this
> list in arch_get_memory_phys_device to determine the zero-based index of the
> physical memory device each new memblock belongs to.
>
> For initial memory or for non-acpi/hotplug enabled systems, phys_device is
> always -1.
>
> Signed-off-by: Vasilis Liaskovitis <vasilis.liaskovitis@...fitbricks.com>
> ---
> Documentation/ABI/testing/sysfs-devices-memory | 8 ++++++-
> drivers/acpi/acpi_memhotplug.c | 27 ++++++++++++++++++++++++
> drivers/base/memory.c | 7 +++++-
> include/linux/acpi.h | 2 +
> 4 files changed, 42 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory
> index 7405de2..290c62a 100644
> --- a/Documentation/ABI/testing/sysfs-devices-memory
> +++ b/Documentation/ABI/testing/sysfs-devices-memory
> @@ -27,7 +27,13 @@ Contact: Badari Pulavarty <pbadari@...ibm.com>
> Description:
> The file /sys/devices/system/memory/memoryX/phys_device
> is read-only and is designed to show the name of physical
> - memory device. Implementation is currently incomplete.
> + memory device. Implementation is currently incomplete. In a
> + system with CONFIG_ACPI_HOTPLUG_MEMORY=n, phys_device is always
> + -1. In a system with CONFIG_ACPI_HOTPLUG_MEMORY=y, phys_device
> + is -1 for all initial / non-hot-removable memory. For
> + memory that has been hot-plugged, phys_device will return the
> + zero-based index of the physical device that this memory block
> + belongs to. Indices are determined by hotplug order.
>
> What: /sys/devices/system/memory/memoryX/phys_index
> Date: September 2008
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 3be9501..4154dc5 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -48,6 +48,7 @@ ACPI_MODULE_NAME("acpi_memhotplug");
> #define MEMORY_POWER_ON_STATE 1
> #define MEMORY_POWER_OFF_STATE 2
>
> +static LIST_HEAD(acpi_mem_device_list);
> static int acpi_memory_device_add(struct acpi_device *device,
> const struct acpi_device_id *not_used);
> static void acpi_memory_device_remove(struct acpi_device *device);
> @@ -81,6 +82,7 @@ struct acpi_memory_device {
> struct acpi_device * device;
> unsigned int state; /* State of the memory device */
> struct list_head res_list;
> + struct list_head mem_device_list;
> };
>
> static acpi_status
> @@ -287,6 +289,7 @@ static int acpi_memory_device_add(struct acpi_device *device,
> return -ENOMEM;
>
> INIT_LIST_HEAD(&mem_device->res_list);
> + INIT_LIST_HEAD(&mem_device->mem_device_list);
> mem_device->device = device;
> sprintf(acpi_device_name(device), "%s", ACPI_MEMORY_DEVICE_NAME);
> sprintf(acpi_device_class(device), "%s", ACPI_MEMORY_DEVICE_CLASS);
> @@ -308,9 +311,11 @@ static int acpi_memory_device_add(struct acpi_device *device,
> return 0;
> }
>
> + list_add_tail(&mem_device->mem_device_list, &acpi_mem_device_list);
> result = acpi_memory_enable_device(mem_device);
> if (result) {
> dev_err(&device->dev, "acpi_memory_enable_device() error\n");
> + list_del(&mem_device->mem_device_list);
> acpi_memory_device_free(mem_device);
> return -ENODEV;
> }
> @@ -328,9 +333,31 @@ static void acpi_memory_device_remove(struct acpi_device *device)
>
> mem_device = acpi_driver_data(device);
> acpi_memory_remove_memory(mem_device);
> + list_del(&mem_device->mem_device_list);
> acpi_memory_device_free(mem_device);
> }
>
> +int acpi_memory_phys_device(unsigned long start_pfn)
> +{
> + struct acpi_memory_device *mem_dev;
> + struct acpi_memory_info *info;
> + unsigned long start_addr = start_pfn << PAGE_SHIFT;
> + int id = 0;
> +
> + list_for_each_entry(mem_dev, &acpi_mem_device_list, mem_device_list) {
> + list_for_each_entry(info, &mem_dev->res_list, list) {
> + if ((info->start_addr <= start_addr) &&
> + (info->start_addr + info->length > start_addr))
> + return id;
> + }
> + id++;
> + }
I don't think this solve your problem.
When hot adding memory device in my system, consecutive index number is
applied to PNP0C80 as follows:
$ ls /sys/bus/acpi/devices/ |grep PNP0C80
PNP0C80:00
PNP0C80:01 => hot added memory device
PNP0C80:02 => hot added memory device
In this case, we can know PNP0C80:YY by memoryXX/phys_device file.
But if hot removing and adding the same device, index number is changed
as follows:
$ ls /sys/bus/acpi/devices/
PNP0C80:00
PNP0C80:03 => hot added memory device
PNP0C80:04 => hot added memory device
In this case, we cannot know PNP0C80:YY by memoryXX/phys_device file.
Thanks,
Yasuaki Ishimatsu
> +
> + /* Memory not associated with a hot-pluggable device gets -1. For
> + * example, initial memory. */
> + return -1;
> +}
> +
> void __init acpi_memory_hotplug_init(void)
> {
> acpi_scan_add_handler_with_hotplug(&memory_device_handler, "memory");
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 8300a18..2cc98df 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -22,6 +22,7 @@
> #include <linux/mutex.h>
> #include <linux/stat.h>
> #include <linux/slab.h>
> +#include <linux/acpi.h>
>
> #include <linux/atomic.h>
> #include <asm/uaccess.h>
> @@ -522,7 +523,11 @@ static inline int memory_fail_init(void)
> */
> int __weak arch_get_memory_phys_device(unsigned long start_pfn)
> {
> - return 0;
> +#ifdef CONFIG_ACPI_HOTPLUG_MEMORY
> + return acpi_memory_phys_device(start_pfn);
> +#else
> + return -1;
> +#endif
> }
>
> /*
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index f46cfd7..00302fc 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -562,6 +562,8 @@ static inline __printf(3, 4) void
> acpi_handle_printk(const char *level, void *handle, const char *fmt, ...) {}
> #endif /* !CONFIG_ACPI */
>
> +int acpi_memory_phys_device(unsigned long start_pfn);
> +
> /*
> * acpi_handle_<level>: Print message with ACPI prefix and object path
> *
>
--
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