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Message-ID: <50652C31.1090706@gmail.com>
Date: Fri, 28 Sep 2012 12:48:49 +0800
From: Ni zhan Chen <nizhan.chen@...il.com>
To: wency@...fujitsu.com
CC: x86@...nel.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org,
linuxppc-dev@...ts.ozlabs.org, linux-acpi@...r.kernel.org,
linux-s390@...r.kernel.org, linux-sh@...r.kernel.org,
linux-ia64@...r.kernel.org, cmetcalf@...era.com,
sparclinux@...r.kernel.org, rientjes@...gle.com, liuj97@...il.com,
len.brown@...el.com, benh@...nel.crashing.org, paulus@...ba.org,
cl@...ux.com, minchan.kim@...il.com, akpm@...ux-foundation.org,
kosaki.motohiro@...fujitsu.com, isimatu.yasuaki@...fujitsu.com
Subject: Re: [RFC v9 PATCH 04/21] memory-hotplug: offline and remove memory
when removing the memory device
On 09/05/2012 05:25 PM, wency@...fujitsu.com wrote:
> From: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
>
> We should offline and remove memory when removing the memory device.
> The memory device can be removed by 2 ways:
> 1. send eject request by SCI
> 2. echo 1 >/sys/bus/pci/devices/PNP0C80:XX/eject
>
> In the 1st case, acpi_memory_disable_device() will be called. In the 2nd
> case, acpi_memory_device_remove() will be called. acpi_memory_device_remove()
> will also be called when we unbind the memory device from the driver
> acpi_memhotplug. If the type is ACPI_BUS_REMOVAL_EJECT, it means
> that the user wants to eject the memory device, and we should offline
> and remove memory in acpi_memory_device_remove().
>
> The function remove_memory() is not implemeted now. It only check whether
> all memory has been offllined now.
>
> CC: David Rientjes <rientjes@...gle.com>
> CC: Jiang Liu <liuj97@...il.com>
> CC: Len Brown <len.brown@...el.com>
> CC: Benjamin Herrenschmidt <benh@...nel.crashing.org>
> CC: Paul Mackerras <paulus@...ba.org>
> CC: Christoph Lameter <cl@...ux.com>
> Cc: Minchan Kim <minchan.kim@...il.com>
> CC: Andrew Morton <akpm@...ux-foundation.org>
> CC: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@...fujitsu.com>
> Signed-off-by: Wen Congyang <wency@...fujitsu.com>
> ---
> drivers/acpi/acpi_memhotplug.c | 45 +++++++++++++++++++++++++++++++++------
> drivers/base/memory.c | 39 ++++++++++++++++++++++++++++++++++
> include/linux/memory.h | 5 ++++
> include/linux/memory_hotplug.h | 5 ++++
> mm/memory_hotplug.c | 22 +++++++++++++++++++
> 5 files changed, 109 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
> index 7873832..9d47458 100644
> --- a/drivers/acpi/acpi_memhotplug.c
> +++ b/drivers/acpi/acpi_memhotplug.c
> @@ -29,6 +29,7 @@
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/types.h>
> +#include <linux/memory.h>
> #include <linux/memory_hotplug.h>
> #include <linux/slab.h>
> #include <acpi/acpi_drivers.h>
> @@ -310,25 +311,44 @@ static int acpi_memory_powerdown_device(struct acpi_memory_device *mem_device)
> return 0;
> }
>
> -static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
> +static int
> +acpi_memory_device_remove_memory(struct acpi_memory_device *mem_device)
> {
> int result;
> struct acpi_memory_info *info, *n;
> + int node = mem_device->nid;
>
> -
> - /*
> - * Ask the VM to offline this memory range.
> - * Note: Assume that this function returns zero on success
> - */
> list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
> if (info->enabled) {
> result = offline_memory(info->start_addr, info->length);
> if (result)
> return result;
> +
> + result = remove_memory(node, info->start_addr,
> + info->length);
> + if (result)
> + return result;
> }
> +
> + list_del(&info->list);
> kfree(info);
> }
>
> + return 0;
> +}
> +
> +static int acpi_memory_disable_device(struct acpi_memory_device *mem_device)
> +{
> + int result;
> +
> + /*
> + * Ask the VM to offline this memory range.
> + * Note: Assume that this function returns zero on success
> + */
> + result = acpi_memory_device_remove_memory(mem_device);
> + if (result)
> + return result;
> +
> /* Power-off and eject the device */
> result = acpi_memory_powerdown_device(mem_device);
> if (result) {
> @@ -477,12 +497,23 @@ static int acpi_memory_device_add(struct acpi_device *device)
> static int acpi_memory_device_remove(struct acpi_device *device, int type)
> {
> struct acpi_memory_device *mem_device = NULL;
> -
> + int result;
>
> if (!device || !acpi_driver_data(device))
> return -EINVAL;
>
> mem_device = acpi_driver_data(device);
> +
> + if (type == ACPI_BUS_REMOVAL_EJECT) {
> + /*
> + * offline and remove memory only when the memory device is
> + * ejected.
> + */
> + result = acpi_memory_device_remove_memory(mem_device);
> + if (result)
> + return result;
> + }
> +
> kfree(mem_device);
>
> return 0;
> diff --git a/drivers/base/memory.c b/drivers/base/memory.c
> index 86c8821..038be73 100644
> --- a/drivers/base/memory.c
> +++ b/drivers/base/memory.c
> @@ -70,6 +70,45 @@ void unregister_memory_isolate_notifier(struct notifier_block *nb)
> }
> EXPORT_SYMBOL(unregister_memory_isolate_notifier);
>
> +bool is_memblk_offline(unsigned long start, unsigned long size)
> +{
> + struct memory_block *mem = NULL;
> + struct mem_section *section;
> + unsigned long start_pfn, end_pfn;
> + unsigned long pfn, section_nr;
> +
> + start_pfn = PFN_DOWN(start);
> + end_pfn = PFN_UP(start + size);
> +
> + for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
> + section_nr = pfn_to_section_nr(pfn);
> + if (!present_section_nr(section_nr))
> + continue;
> +
> + section = __nr_to_section(section_nr);
> + /* same memblock? */
> + if (mem)
> + if ((section_nr >= mem->start_section_nr) &&
> + (section_nr <= mem->end_section_nr))
> + continue;
> +
> + mem = find_memory_block_hinted(section, mem);
> + if (!mem)
> + continue;
> + if (mem->state == MEM_OFFLINE)
> + continue;
> +
> + kobject_put(&mem->dev.kobj);
> + return false;
> + }
> +
> + if (mem)
> + kobject_put(&mem->dev.kobj);
> +
> + return true;
> +}
> +EXPORT_SYMBOL(is_memblk_offline);
> +
> /*
> * register_memory - Setup a sysfs device for a memory block
> */
> diff --git a/include/linux/memory.h b/include/linux/memory.h
> index 1ac7f6e..7c66126 100644
> --- a/include/linux/memory.h
> +++ b/include/linux/memory.h
> @@ -106,6 +106,10 @@ static inline int memory_isolate_notify(unsigned long val, void *v)
> {
> return 0;
> }
> +static inline bool is_memblk_offline(unsigned long start, unsigned long size)
> +{
> + return false;
> +}
> #else
> extern int register_memory_notifier(struct notifier_block *nb);
> extern void unregister_memory_notifier(struct notifier_block *nb);
> @@ -120,6 +124,7 @@ extern int memory_isolate_notify(unsigned long val, void *v);
> extern struct memory_block *find_memory_block_hinted(struct mem_section *,
> struct memory_block *);
> extern struct memory_block *find_memory_block(struct mem_section *);
> +extern bool is_memblk_offline(unsigned long start, unsigned long size);
> #define CONFIG_MEM_BLOCK_SIZE (PAGES_PER_SECTION<<PAGE_SHIFT)
> enum mem_add_context { BOOT, HOTPLUG };
> #endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 0b040bb..fd84ea9 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -222,6 +222,7 @@ static inline void unlock_memory_hotplug(void) {}
> #ifdef CONFIG_MEMORY_HOTREMOVE
>
> extern int is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
> +extern int remove_memory(int nid, u64 start, u64 size);
>
> #else
> static inline int is_mem_section_removable(unsigned long pfn,
> @@ -229,6 +230,10 @@ static inline int is_mem_section_removable(unsigned long pfn,
> {
> return 0;
> }
> +static inline int remove_memory(int nid, u64 start, u64 size)
> +{
> + return -EBUSY;
> +}
> #endif /* CONFIG_MEMORY_HOTREMOVE */
>
> extern int mem_online_node(int nid);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 6fc1908..49f7747 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -1038,6 +1038,28 @@ int offline_memory(u64 start, u64 size)
>
> return 0;
> }
> +
> +int remove_memory(int nid, u64 start, u64 size)
> +{
> + int ret = -EBUSY;
> + lock_memory_hotplug();
> + /*
> + * The memory might become online by other task, even if you offine it.
s/offine/offline
> + * So we check whether the memory has been onlined or not.
> + */
> + if (!is_memblk_offline(start, size)) {
> + pr_warn("memory removing [mem %#010llx-%#010llx] failed, "
> + "because the memmory range is online\n",
> + start, start + size);
> + ret = -EAGAIN;
> + }
> +
> + unlock_memory_hotplug();
> + return ret;
> +
> +}
> +EXPORT_SYMBOL_GPL(remove_memory);
> +
> #else
> int offline_pages(unsigned long start, unsigned long size)
> {
--
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