Commit ecbd5d7c authored by Ma Wupeng's avatar Ma Wupeng Committed by Wupeng Ma
Browse files

mm: page_eject: Introuduce page ejection 

hulk inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8K5CO



--------------------------------

Page ejection is achieved by soft_offline_page and unpoison_memory. A
linked list is maintained to log the pfns which are offlined by this
module. Only the pfns present in the list is allowed to go online.

The follow sysfs is introduced to online/offline page via this
module, since there is a internal linked list to record all
offlined pages, remove_page is introduced when a user no longer
wishes to online this particular page. To reduce the length of
the internal list, this function removes the specified page from
the list.

- /sys/kernel/page_eject/online_page
- /sys/kernel/page_eject/offline_page
- /sys/kernel/page_eject/remove_page

Signed-off-by: default avatarMa Wupeng <mawupeng1@huawei.com>
parent 7b39f862

drivers/ras/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -29,6 +29,16 @@ menuconfig RAS 
	  so have ideal availability, but may be unreliable, with frequent

	  data corruption.



config PAGE_EJECT

	tristate "page eject"

	default m

	depends on MEMORY_FAILURE

	help

	  Used to eject page, which is achieved by soft_offline_page and

	  unpoison_memory. A linked list is maintained to log the pfns

	  which are offlined by this module. Only the pfns present in the

	  list is allowed to go online.



if RAS



source "arch/x86/ras/Kconfig"

drivers/ras/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -2,3 +2,4 @@ 
obj-$(CONFIG_RAS)	+= ras.o

obj-$(CONFIG_DEBUG_FS)	+= debugfs.o

obj-$(CONFIG_RAS_CEC)	+= cec.o

obj-$(CONFIG_PAGE_EJECT)	+= page_eject.o

drivers/ras/page_eject.c

0 → 100644
+248 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Copyright (C) Huawei Technologies Co., Ltd. 2023. All rights reserved.

 */



#define pr_fmt(fmt) "page eject: " fmt



#include <linux/mm.h>

#include <linux/module.h>

#include <linux/slab.h>



static struct list_head eject_page_list = LIST_HEAD_INIT(eject_page_list);

static DEFINE_MUTEX(eject_page_mutex);

static struct kobject *eject_page_kobj;



struct ejected_pfn {

	struct list_head list;

	unsigned long pfn;

};



static struct ejected_pfn *page_eject_remove_pfn_locked(unsigned long pfn)

{

	struct ejected_pfn *item = NULL, *next;



	mutex_lock(&eject_page_mutex);

	list_for_each_entry_safe(item, next, &eject_page_list, list) {

		if (pfn == item->pfn) {

			list_del(&item->list);

			break;

		}

	}

	mutex_unlock(&eject_page_mutex);



	return item;

}



static void page_eject_add_pfn_locked(struct ejected_pfn *item)

{

	mutex_lock(&eject_page_mutex);

	list_add_tail(&item->list, &eject_page_list);

	mutex_unlock(&eject_page_mutex);

}



static void page_eject_clear_list_locked(void)

{

	struct ejected_pfn *item, *next;



	mutex_lock(&eject_page_mutex);

	list_for_each_entry_safe(item, next, &eject_page_list, list) {

		list_del(&item->list);

		kfree(item);

	}

	mutex_unlock(&eject_page_mutex);

}



static int page_eject_offline_page(unsigned long pfn)

{

	struct ejected_pfn *item;

	struct page *page;

	int ret;



	page = pfn_to_online_page(pfn);

	if (!page)

		return -EINVAL;



	if (PageHWPoison(page)) {

		pr_err("page fail to be offlined, page is already offlined, pfn: %#lx\n", pfn);

		return -EINVAL;

	}



	item = kzalloc(sizeof(struct ejected_pfn), GFP_KERNEL);

	if (!item)

		return -ENOMEM;



	/*

	 * if soft_offline_page return 0 because PageHWPoison, this pfn

	 * will add to list and this add will be removed during online

	 * since it is poisoned.

	 */

	ret = soft_offline_page(pfn, 0);

	if (ret) {

		pr_err("page fail to be offlined, soft_offline_page failed(%d), pfn=%#lx\n",

		       ret, pfn);

		kfree(item);

		return ret;

	}



	item->pfn = pfn;



	page_eject_add_pfn_locked(item);



	return 0;

}



static int page_eject_online_page(unsigned long pfn)

{

	struct ejected_pfn *item;

	struct page *page;

	int ret;



	page = pfn_to_online_page(pfn);

	if (!page)

		return -EINVAL;



	item = page_eject_remove_pfn_locked(pfn);

	if (!item) {

		pr_err("page failed to be onlined, pfn: %#lx\n", pfn);

		return -EINVAL;

	}



	ret = unpoison_memory(pfn);

	if (!ret) {

		kfree(item);

		return ret;

	}



	/* re-add pfn to list if unpoison failed */

	page_eject_add_pfn_locked(item);

	pr_err("page failed to be onlined, unpoison_memory error(%d), pfn: %#lx\n",

		ret, pfn);

	return ret;

}



static int page_eject_remove_page(unsigned long pfn)

{

	struct ejected_pfn *item;



	item = page_eject_remove_pfn_locked(pfn);

	if (!item) {

		pr_info("page fail to be removed, pfn: %#lx\n", pfn);

		return -EINVAL;

	}



	kfree(item);



	return 0;

}



static ssize_t offline_store(struct kobject *kobj, struct kobj_attribute *attr,

			     const char *buf, size_t count)

{

	u64 paddr;

	int res;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	if (kstrtoull(buf, 16, &paddr))

		return -EINVAL;



	res = page_eject_offline_page(paddr >> PAGE_SHIFT);

	if (res)

		return res;



	return count;

}



static ssize_t online_store(struct kobject *kobj, struct kobj_attribute *attr,

			    const char *buf, size_t count)

{

	u64 paddr;

	int res;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	if (kstrtoull(buf, 16, &paddr))

		return -EINVAL;



	res = page_eject_online_page(paddr >> PAGE_SHIFT);

	if (res)

		return res;



	return count;

}



static ssize_t remove_store(struct kobject *kobj, struct kobj_attribute *attr,

			    const char *buf, size_t count)

{

	u64 paddr;

	int res;



	if (!capable(CAP_SYS_ADMIN))

		return -EPERM;



	if (kstrtoull(buf, 16, &paddr))

		return -EINVAL;



	res = page_eject_remove_page(paddr >> PAGE_SHIFT);

	if (res)

		return res;



	return count;

}



static struct kobj_attribute online_attr =

	__ATTR(online_page, 0200, NULL, online_store);

static struct kobj_attribute offline_attr =

	__ATTR(offline_page, 0200, NULL, offline_store);

static struct kobj_attribute remove_attr =

	__ATTR(remove_page, 0200, NULL, remove_store);



static struct attribute *eject_page_attrs[] = {

	&offline_attr.attr,

	&online_attr.attr,

	&remove_attr.attr,

	NULL,

};



static struct attribute_group eject_page_attr_group = {

	.attrs = eject_page_attrs,

};



static int __init page_eject_init(void)

{

	int ret = -ENOMEM;



	eject_page_kobj = kobject_create_and_add("page_eject", kernel_kobj);

	if (!eject_page_kobj)

		return ret;



	ret = sysfs_create_group(eject_page_kobj, &eject_page_attr_group);

	if (ret) {

		kobject_put(eject_page_kobj);

		return ret;

	}



	mutex_init(&eject_page_mutex);



	pr_info("init page eject succeed\n");

	return ret;

}



static void __exit page_eject_exit(void)

{

	page_eject_clear_list_locked();



	kobject_put(eject_page_kobj);



	pr_info("exit page eject succeed\n");

}



module_init(page_eject_init);

module_exit(page_eject_exit);



MODULE_LICENSE("GPL");

MODULE_AUTHOR("Ma Wupeng <mawupeng1@huawei.com>");

MODULE_DESCRIPTION("page eject");