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41 results

memory.c

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    Nathan Fontenot authored and Greg Kroah-Hartman committed
    Add a section count property to the memory_block struct to track the number
    of memory sections that have been added/removed from a memory block. This
    allows us to know when the last memory section of a memory block has been
    removed so we can remove the memory block.
    
    Signed-off-by: default avatarNathan Fontenot <nfont@austin.ibm.com>
    Reviewed-by: default avatarRobin Holt <holt@sgi.com>
    Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
    
    07681215
    History
    memory.c 14.31 KiB
    /*
     * drivers/base/memory.c - basic Memory class support
     *
     * Written by Matt Tolentino <matthew.e.tolentino@intel.com>
     *            Dave Hansen <haveblue@us.ibm.com>
     *
     * This file provides the necessary infrastructure to represent
     * a SPARSEMEM-memory-model system's physical memory in /sysfs.
     * All arch-independent code that assumes MEMORY_HOTPLUG requires
     * SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
     */
    
    #include <linux/sysdev.h>
    #include <linux/module.h>
    #include <linux/init.h>
    #include <linux/topology.h>
    #include <linux/capability.h>
    #include <linux/device.h>
    #include <linux/memory.h>
    #include <linux/kobject.h>
    #include <linux/memory_hotplug.h>
    #include <linux/mm.h>
    #include <linux/mutex.h>
    #include <linux/stat.h>
    #include <linux/slab.h>
    
    #include <asm/atomic.h>
    #include <asm/uaccess.h>
    
    static DEFINE_MUTEX(mem_sysfs_mutex);
    
    #define MEMORY_CLASS_NAME	"memory"
    
    static struct sysdev_class memory_sysdev_class = {
    	.name = MEMORY_CLASS_NAME,
    };
    
    static const char *memory_uevent_name(struct kset *kset, struct kobject *kobj)
    {
    	return MEMORY_CLASS_NAME;
    }
    
    static int memory_uevent(struct kset *kset, struct kobject *obj, struct kobj_uevent_env *env)
    {
    	int retval = 0;
    
    	return retval;
    }
    
    static const struct kset_uevent_ops memory_uevent_ops = {
    	.name		= memory_uevent_name,
    	.uevent		= memory_uevent,
    };
    
    static BLOCKING_NOTIFIER_HEAD(memory_chain);
    
    int register_memory_notifier(struct notifier_block *nb)
    {
            return blocking_notifier_chain_register(&memory_chain, nb);
    }
    EXPORT_SYMBOL(register_memory_notifier);
    
    void unregister_memory_notifier(struct notifier_block *nb)
    {
            blocking_notifier_chain_unregister(&memory_chain, nb);
    }
    EXPORT_SYMBOL(unregister_memory_notifier);
    
    static ATOMIC_NOTIFIER_HEAD(memory_isolate_chain);
    
    int register_memory_isolate_notifier(struct notifier_block *nb)
    {
    	return atomic_notifier_chain_register(&memory_isolate_chain, nb);
    }
    EXPORT_SYMBOL(register_memory_isolate_notifier);
    
    void unregister_memory_isolate_notifier(struct notifier_block *nb)
    {
    	atomic_notifier_chain_unregister(&memory_isolate_chain, nb);
    }
    EXPORT_SYMBOL(unregister_memory_isolate_notifier);
    
    /*
     * register_memory - Setup a sysfs device for a memory block
     */
    static
    int register_memory(struct memory_block *memory, struct mem_section *section)
    {
    	int error;
    
    	memory->sysdev.cls = &memory_sysdev_class;
    	memory->sysdev.id = __section_nr(section);
    
    	error = sysdev_register(&memory->sysdev);
    	return error;
    }
    
    static void
    unregister_memory(struct memory_block *memory, struct mem_section *section)
    {
    	BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
    	BUG_ON(memory->sysdev.id != __section_nr(section));
    
    	/* drop the ref. we got in remove_memory_block() */
    	kobject_put(&memory->sysdev.kobj);
    	sysdev_unregister(&memory->sysdev);
    }
    
    /*
     * use this as the physical section index that this memsection
     * uses.
     */
    
    static ssize_t show_mem_phys_index(struct sys_device *dev,
    			struct sysdev_attribute *attr, char *buf)
    {
    	struct memory_block *mem =
    		container_of(dev, struct memory_block, sysdev);
    	return sprintf(buf, "%08lx\n", mem->phys_index);
    }
    
    /*
     * Show whether the section of memory is likely to be hot-removable
     */
    static ssize_t show_mem_removable(struct sys_device *dev,
    			struct sysdev_attribute *attr, char *buf)
    {
    	unsigned long start_pfn;
    	int ret;
    	struct memory_block *mem =
    		container_of(dev, struct memory_block, sysdev);
    
    	start_pfn = section_nr_to_pfn(mem->phys_index);
    	ret = is_mem_section_removable(start_pfn, PAGES_PER_SECTION);
    	return sprintf(buf, "%d\n", ret);
    }
    
    /*
     * online, offline, going offline, etc.
     */
    static ssize_t show_mem_state(struct sys_device *dev,
    			struct sysdev_attribute *attr, char *buf)
    {
    	struct memory_block *mem =
    		container_of(dev, struct memory_block, sysdev);
    	ssize_t len = 0;
    
    	/*
    	 * We can probably put these states in a nice little array
    	 * so that they're not open-coded
    	 */
    	switch (mem->state) {
    		case MEM_ONLINE:
    			len = sprintf(buf, "online\n");
    			break;
    		case MEM_OFFLINE:
    			len = sprintf(buf, "offline\n");
    			break;
    		case MEM_GOING_OFFLINE:
    			len = sprintf(buf, "going-offline\n");
    			break;
    		default:
    			len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
    					mem->state);
    			WARN_ON(1);
    			break;
    	}
    
    	return len;
    }
    
    int memory_notify(unsigned long val, void *v)
    {
    	return blocking_notifier_call_chain(&memory_chain, val, v);
    }
    
    int memory_isolate_notify(unsigned long val, void *v)
    {
    	return atomic_notifier_call_chain(&memory_isolate_chain, val, v);
    }
    
    /*
     * MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
     * OK to have direct references to sparsemem variables in here.
     */
    static int
    memory_block_action(struct memory_block *mem, unsigned long action)
    {
    	int i;
    	unsigned long psection;
    	unsigned long start_pfn, start_paddr;
    	struct page *first_page;
    	int ret;
    	int old_state = mem->state;
    
    	psection = mem->phys_index;
    	first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
    
    	/*
    	 * The probe routines leave the pages reserved, just
    	 * as the bootmem code does.  Make sure they're still
    	 * that way.
    	 */
    	if (action == MEM_ONLINE) {
    		for (i = 0; i < PAGES_PER_SECTION; i++) {
    			if (PageReserved(first_page+i))
    				continue;
    
    			printk(KERN_WARNING "section number %ld page number %d "
    				"not reserved, was it already online? \n",
    				psection, i);
    			return -EBUSY;
    		}
    	}
    
    	switch (action) {
    		case MEM_ONLINE:
    			start_pfn = page_to_pfn(first_page);
    			ret = online_pages(start_pfn, PAGES_PER_SECTION);
    			break;
    		case MEM_OFFLINE:
    			mem->state = MEM_GOING_OFFLINE;
    			start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
    			ret = remove_memory(start_paddr,
    					    PAGES_PER_SECTION << PAGE_SHIFT);
    			if (ret) {
    				mem->state = old_state;
    				break;
    			}
    			break;
    		default:
    			WARN(1, KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
    					__func__, mem, action, action);
    			ret = -EINVAL;
    	}
    
    	return ret;
    }
    
    static int memory_block_change_state(struct memory_block *mem,
    		unsigned long to_state, unsigned long from_state_req)
    {
    	int ret = 0;
    	mutex_lock(&mem->state_mutex);
    
    	if (mem->state != from_state_req) {
    		ret = -EINVAL;
    		goto out;
    	}
    
    	ret = memory_block_action(mem, to_state);
    	if (!ret)
    		mem->state = to_state;
    
    out:
    	mutex_unlock(&mem->state_mutex);
    	return ret;
    }
    
    static ssize_t
    store_mem_state(struct sys_device *dev,
    		struct sysdev_attribute *attr, const char *buf, size_t count)
    {
    	struct memory_block *mem;
    	unsigned int phys_section_nr;
    	int ret = -EINVAL;
    
    	mem = container_of(dev, struct memory_block, sysdev);
    	phys_section_nr = mem->phys_index;
    
    	if (!present_section_nr(phys_section_nr))
    		goto out;
    
    	if (!strncmp(buf, "online", min((int)count, 6)))
    		ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
    	else if(!strncmp(buf, "offline", min((int)count, 7)))
    		ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
    out:
    	if (ret)
    		return ret;
    	return count;
    }
    
    /*
     * phys_device is a bad name for this.  What I really want
     * is a way to differentiate between memory ranges that
     * are part of physical devices that constitute
     * a complete removable unit or fru.
     * i.e. do these ranges belong to the same physical device,
     * s.t. if I offline all of these sections I can then
     * remove the physical device?
     */
    static ssize_t show_phys_device(struct sys_device *dev,
    				struct sysdev_attribute *attr, char *buf)
    {
    	struct memory_block *mem =
    		container_of(dev, struct memory_block, sysdev);
    	return sprintf(buf, "%d\n", mem->phys_device);
    }
    
    static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
    static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
    static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
    static SYSDEV_ATTR(removable, 0444, show_mem_removable, NULL);
    
    #define mem_create_simple_file(mem, attr_name)	\
    	sysdev_create_file(&mem->sysdev, &attr_##attr_name)
    #define mem_remove_simple_file(mem, attr_name)	\
    	sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
    
    /*
     * Block size attribute stuff
     */
    static ssize_t
    print_block_size(struct sysdev_class *class, struct sysdev_class_attribute *attr,
    		 char *buf)
    {
    	return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
    }
    
    static SYSDEV_CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
    
    static int block_size_init(void)
    {
    	return sysfs_create_file(&memory_sysdev_class.kset.kobj,
    				&attr_block_size_bytes.attr);
    }
    
    /*
     * Some architectures will have custom drivers to do this, and
     * will not need to do it from userspace.  The fake hot-add code
     * as well as ppc64 will do all of their discovery in userspace
     * and will require this interface.
     */
    #ifdef CONFIG_ARCH_MEMORY_PROBE
    static ssize_t
    memory_probe_store(struct class *class, struct class_attribute *attr,
    		   const char *buf, size_t count)
    {
    	u64 phys_addr;
    	int nid;
    	int ret;
    
    	phys_addr = simple_strtoull(buf, NULL, 0);
    
    	nid = memory_add_physaddr_to_nid(phys_addr);
    	ret = add_memory(nid, phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
    
    	if (ret)
    		count = ret;
    
    	return count;
    }
    static CLASS_ATTR(probe, S_IWUSR, NULL, memory_probe_store);
    
    static int memory_probe_init(void)
    {
    	return sysfs_create_file(&memory_sysdev_class.kset.kobj,
    				&class_attr_probe.attr);
    }
    #else
    static inline int memory_probe_init(void)
    {
    	return 0;
    }
    #endif
    
    #ifdef CONFIG_MEMORY_FAILURE
    /*
     * Support for offlining pages of memory
     */
    
    /* Soft offline a page */
    static ssize_t
    store_soft_offline_page(struct class *class,
    			struct class_attribute *attr,
    			const char *buf, size_t count)
    {
    	int ret;
    	u64 pfn;
    	if (!capable(CAP_SYS_ADMIN))
    		return -EPERM;
    	if (strict_strtoull(buf, 0, &pfn) < 0)
    		return -EINVAL;
    	pfn >>= PAGE_SHIFT;
    	if (!pfn_valid(pfn))
    		return -ENXIO;
    	ret = soft_offline_page(pfn_to_page(pfn), 0);
    	return ret == 0 ? count : ret;
    }
    
    /* Forcibly offline a page, including killing processes. */
    static ssize_t
    store_hard_offline_page(struct class *class,
    			struct class_attribute *attr,
    			const char *buf, size_t count)
    {
    	int ret;
    	u64 pfn;
    	if (!capable(CAP_SYS_ADMIN))
    		return -EPERM;
    	if (strict_strtoull(buf, 0, &pfn) < 0)
    		return -EINVAL;
    	pfn >>= PAGE_SHIFT;
    	ret = __memory_failure(pfn, 0, 0);
    	return ret ? ret : count;
    }
    
    static CLASS_ATTR(soft_offline_page, 0644, NULL, store_soft_offline_page);
    static CLASS_ATTR(hard_offline_page, 0644, NULL, store_hard_offline_page);
    
    static __init int memory_fail_init(void)
    {
    	int err;
    
    	err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
    				&class_attr_soft_offline_page.attr);
    	if (!err)
    		err = sysfs_create_file(&memory_sysdev_class.kset.kobj,
    				&class_attr_hard_offline_page.attr);
    	return err;
    }
    #else
    static inline int memory_fail_init(void)
    {
    	return 0;
    }
    #endif
    
    /*
     * Note that phys_device is optional.  It is here to allow for
     * differentiation between which *physical* devices each
     * section belongs to...
     */
    int __weak arch_get_memory_phys_device(unsigned long start_pfn)
    {
    	return 0;
    }
    
    struct memory_block *find_memory_block_hinted(struct mem_section *section,
    					      struct memory_block *hint)
    {
    	struct kobject *kobj;
    	struct sys_device *sysdev;
    	struct memory_block *mem;
    	char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
    
    	kobj = hint ? &hint->sysdev.kobj : NULL;
    
    	/*
    	 * This only works because we know that section == sysdev->id
    	 * slightly redundant with sysdev_register()
    	 */
    	sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
    
    	kobj = kset_find_obj_hinted(&memory_sysdev_class.kset, name, kobj);
    	if (!kobj)
    		return NULL;
    
    	sysdev = container_of(kobj, struct sys_device, kobj);
    	mem = container_of(sysdev, struct memory_block, sysdev);
    
    	return mem;
    }
    
    /*
     * For now, we have a linear search to go find the appropriate
     * memory_block corresponding to a particular phys_index. If
     * this gets to be a real problem, we can always use a radix
     * tree or something here.
     *
     * This could be made generic for all sysdev classes.
     */
    struct memory_block *find_memory_block(struct mem_section *section)
    {
    	return find_memory_block_hinted(section, NULL);
    }
    
    static int add_memory_block(int nid, struct mem_section *section,
    			unsigned long state, enum mem_add_context context)
    {
    	struct memory_block *mem = kzalloc(sizeof(*mem), GFP_KERNEL);
    	unsigned long start_pfn;
    	int ret = 0;
    
    	if (!mem)
    		return -ENOMEM;
    
    	mutex_lock(&mem_sysfs_mutex);
    
    	mem->phys_index = __section_nr(section);
    	mem->state = state;
    	mem->section_count++;
    	mutex_init(&mem->state_mutex);
    	start_pfn = section_nr_to_pfn(mem->phys_index);
    	mem->phys_device = arch_get_memory_phys_device(start_pfn);
    
    	ret = register_memory(mem, section);
    	if (!ret)
    		ret = mem_create_simple_file(mem, phys_index);
    	if (!ret)
    		ret = mem_create_simple_file(mem, state);
    	if (!ret)
    		ret = mem_create_simple_file(mem, phys_device);
    	if (!ret)
    		ret = mem_create_simple_file(mem, removable);
    	if (!ret) {
    		if (context == HOTPLUG)
    			ret = register_mem_sect_under_node(mem, nid);
    	}
    
    	mutex_unlock(&mem_sysfs_mutex);
    	return ret;
    }
    
    int remove_memory_block(unsigned long node_id, struct mem_section *section,
    		int phys_device)
    {
    	struct memory_block *mem;
    
    	mutex_lock(&mem_sysfs_mutex);
    	mem = find_memory_block(section);
    
    	mem->section_count--;
    	if (mem->section_count == 0) {
    		unregister_mem_sect_under_nodes(mem);
    		mem_remove_simple_file(mem, phys_index);
    		mem_remove_simple_file(mem, state);
    		mem_remove_simple_file(mem, phys_device);
    		mem_remove_simple_file(mem, removable);
    		unregister_memory(mem, section);
    	}
    
    	mutex_unlock(&mem_sysfs_mutex);
    	return 0;
    }
    
    /*
     * need an interface for the VM to add new memory regions,
     * but without onlining it.
     */
    int register_new_memory(int nid, struct mem_section *section)
    {
    	return add_memory_block(nid, section, MEM_OFFLINE, HOTPLUG);
    }
    
    int unregister_memory_section(struct mem_section *section)
    {
    	if (!present_section(section))
    		return -EINVAL;
    
    	return remove_memory_block(0, section, 0);
    }
    
    /*
     * Initialize the sysfs support for memory devices...
     */
    int __init memory_dev_init(void)
    {
    	unsigned int i;
    	int ret;
    	int err;
    
    	memory_sysdev_class.kset.uevent_ops = &memory_uevent_ops;
    	ret = sysdev_class_register(&memory_sysdev_class);
    	if (ret)
    		goto out;
    
    	/*
    	 * Create entries for memory sections that were found
    	 * during boot and have been initialized
    	 */
    	for (i = 0; i < NR_MEM_SECTIONS; i++) {
    		if (!present_section_nr(i))
    			continue;
    		err = add_memory_block(0, __nr_to_section(i), MEM_ONLINE,
    				       BOOT);
    		if (!ret)
    			ret = err;
    	}
    
    	err = memory_probe_init();
    	if (!ret)
    		ret = err;
    	err = memory_fail_init();
    	if (!ret)
    		ret = err;
    	err = block_size_init();
    	if (!ret)
    		ret = err;
    out:
    	if (ret)
    		printk(KERN_ERR "%s() failed: %d\n", __func__, ret);
    	return ret;
    }