[PATCH] memory hotplug: sysfs and add/remove functions
This adds generic memory add/remove and supporting functions for memory hotplug into a new file as well as a memory hotplug kernel config option. Individual architecture patches will follow. For now, disable memory hotplug when swsusp is enabled. There's a lot of churn there right now. We'll fix it up properly once it calms down. Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com> Signed-off-by: Dave Hansen <haveblue@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Dave Hansen
committed by
Linus Torvalds
Linus Torvalds
parent
bdc8cb9845
commit
3947be1969
455
drivers/base/memory.c
Normal file
455
drivers/base/memory.c
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@@ -0,0 +1,455 @@
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/*
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* drivers/base/memory.c - basic Memory class support
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*
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* Written by Matt Tolentino <matthew.e.tolentino@intel.com>
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* Dave Hansen <haveblue@us.ibm.com>
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*
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* This file provides the necessary infrastructure to represent
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* a SPARSEMEM-memory-model system's physical memory in /sysfs.
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* All arch-independent code that assumes MEMORY_HOTPLUG requires
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* SPARSEMEM should be contained here, or in mm/memory_hotplug.c.
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*/
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#include <linux/sysdev.h>
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/sched.h> /* capable() */
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#include <linux/topology.h>
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#include <linux/device.h>
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#include <linux/memory.h>
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#include <linux/kobject.h>
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#include <linux/memory_hotplug.h>
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#include <linux/mm.h>
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#include <asm/atomic.h>
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#include <asm/uaccess.h>
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#define MEMORY_CLASS_NAME "memory"
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static struct sysdev_class memory_sysdev_class = {
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set_kset_name(MEMORY_CLASS_NAME),
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};
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EXPORT_SYMBOL(memory_sysdev_class);
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static char *memory_hotplug_name(struct kset *kset, struct kobject *kobj)
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{
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return MEMORY_CLASS_NAME;
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}
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static int memory_hotplug(struct kset *kset, struct kobject *kobj, char **envp,
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int num_envp, char *buffer, int buffer_size)
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{
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int retval = 0;
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return retval;
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}
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static struct kset_hotplug_ops memory_hotplug_ops = {
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.name = memory_hotplug_name,
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.hotplug = memory_hotplug,
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};
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static struct notifier_block *memory_chain;
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static int register_memory_notifier(struct notifier_block *nb)
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{
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return notifier_chain_register(&memory_chain, nb);
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}
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static void unregister_memory_notifier(struct notifier_block *nb)
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{
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notifier_chain_unregister(&memory_chain, nb);
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}
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/*
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* register_memory - Setup a sysfs device for a memory block
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*/
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static int
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register_memory(struct memory_block *memory, struct mem_section *section,
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struct node *root)
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{
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int error;
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memory->sysdev.cls = &memory_sysdev_class;
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memory->sysdev.id = __section_nr(section);
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error = sysdev_register(&memory->sysdev);
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if (root && !error)
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error = sysfs_create_link(&root->sysdev.kobj,
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&memory->sysdev.kobj,
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kobject_name(&memory->sysdev.kobj));
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return error;
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}
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static void
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unregister_memory(struct memory_block *memory, struct mem_section *section,
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struct node *root)
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{
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BUG_ON(memory->sysdev.cls != &memory_sysdev_class);
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BUG_ON(memory->sysdev.id != __section_nr(section));
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sysdev_unregister(&memory->sysdev);
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if (root)
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sysfs_remove_link(&root->sysdev.kobj,
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kobject_name(&memory->sysdev.kobj));
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}
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/*
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* use this as the physical section index that this memsection
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* uses.
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*/
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static ssize_t show_mem_phys_index(struct sys_device *dev, char *buf)
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{
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struct memory_block *mem =
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container_of(dev, struct memory_block, sysdev);
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return sprintf(buf, "%08lx\n", mem->phys_index);
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}
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/*
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* online, offline, going offline, etc.
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*/
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static ssize_t show_mem_state(struct sys_device *dev, char *buf)
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{
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struct memory_block *mem =
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container_of(dev, struct memory_block, sysdev);
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ssize_t len = 0;
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/*
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* We can probably put these states in a nice little array
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* so that they're not open-coded
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*/
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switch (mem->state) {
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case MEM_ONLINE:
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len = sprintf(buf, "online\n");
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break;
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case MEM_OFFLINE:
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len = sprintf(buf, "offline\n");
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break;
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case MEM_GOING_OFFLINE:
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len = sprintf(buf, "going-offline\n");
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break;
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default:
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len = sprintf(buf, "ERROR-UNKNOWN-%ld\n",
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mem->state);
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WARN_ON(1);
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break;
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}
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return len;
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}
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static inline int memory_notify(unsigned long val, void *v)
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{
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return notifier_call_chain(&memory_chain, val, v);
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}
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/*
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* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
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* OK to have direct references to sparsemem variables in here.
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*/
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static int
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memory_block_action(struct memory_block *mem, unsigned long action)
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{
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int i;
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unsigned long psection;
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unsigned long start_pfn, start_paddr;
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struct page *first_page;
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int ret;
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int old_state = mem->state;
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psection = mem->phys_index;
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first_page = pfn_to_page(psection << PFN_SECTION_SHIFT);
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/*
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* The probe routines leave the pages reserved, just
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* as the bootmem code does. Make sure they're still
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* that way.
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*/
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if (action == MEM_ONLINE) {
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for (i = 0; i < PAGES_PER_SECTION; i++) {
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if (PageReserved(first_page+i))
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continue;
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printk(KERN_WARNING "section number %ld page number %d "
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"not reserved, was it already online? \n",
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psection, i);
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return -EBUSY;
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}
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}
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switch (action) {
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case MEM_ONLINE:
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start_pfn = page_to_pfn(first_page);
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ret = online_pages(start_pfn, PAGES_PER_SECTION);
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break;
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case MEM_OFFLINE:
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mem->state = MEM_GOING_OFFLINE;
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memory_notify(MEM_GOING_OFFLINE, NULL);
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start_paddr = page_to_pfn(first_page) << PAGE_SHIFT;
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ret = remove_memory(start_paddr,
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PAGES_PER_SECTION << PAGE_SHIFT);
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if (ret) {
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mem->state = old_state;
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break;
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}
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memory_notify(MEM_MAPPING_INVALID, NULL);
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break;
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default:
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printk(KERN_WARNING "%s(%p, %ld) unknown action: %ld\n",
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__FUNCTION__, mem, action, action);
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WARN_ON(1);
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ret = -EINVAL;
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}
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/*
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* For now, only notify on successful memory operations
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*/
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if (!ret)
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memory_notify(action, NULL);
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return ret;
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}
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static int memory_block_change_state(struct memory_block *mem,
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unsigned long to_state, unsigned long from_state_req)
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{
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int ret = 0;
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down(&mem->state_sem);
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if (mem->state != from_state_req) {
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ret = -EINVAL;
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goto out;
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}
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ret = memory_block_action(mem, to_state);
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if (!ret)
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mem->state = to_state;
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out:
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up(&mem->state_sem);
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return ret;
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}
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static ssize_t
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store_mem_state(struct sys_device *dev, const char *buf, size_t count)
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{
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struct memory_block *mem;
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unsigned int phys_section_nr;
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int ret = -EINVAL;
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mem = container_of(dev, struct memory_block, sysdev);
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phys_section_nr = mem->phys_index;
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if (!valid_section_nr(phys_section_nr))
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goto out;
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if (!strncmp(buf, "online", min((int)count, 6)))
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ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
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else if(!strncmp(buf, "offline", min((int)count, 7)))
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ret = memory_block_change_state(mem, MEM_OFFLINE, MEM_ONLINE);
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out:
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if (ret)
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return ret;
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return count;
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}
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/*
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* phys_device is a bad name for this. What I really want
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* is a way to differentiate between memory ranges that
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* are part of physical devices that constitute
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* a complete removable unit or fru.
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* i.e. do these ranges belong to the same physical device,
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* s.t. if I offline all of these sections I can then
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* remove the physical device?
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*/
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static ssize_t show_phys_device(struct sys_device *dev, char *buf)
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{
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struct memory_block *mem =
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container_of(dev, struct memory_block, sysdev);
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return sprintf(buf, "%d\n", mem->phys_device);
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}
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static SYSDEV_ATTR(phys_index, 0444, show_mem_phys_index, NULL);
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static SYSDEV_ATTR(state, 0644, show_mem_state, store_mem_state);
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static SYSDEV_ATTR(phys_device, 0444, show_phys_device, NULL);
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#define mem_create_simple_file(mem, attr_name) \
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sysdev_create_file(&mem->sysdev, &attr_##attr_name)
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#define mem_remove_simple_file(mem, attr_name) \
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sysdev_remove_file(&mem->sysdev, &attr_##attr_name)
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/*
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* Block size attribute stuff
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*/
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static ssize_t
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print_block_size(struct class *class, char *buf)
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{
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return sprintf(buf, "%lx\n", (unsigned long)PAGES_PER_SECTION * PAGE_SIZE);
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}
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static CLASS_ATTR(block_size_bytes, 0444, print_block_size, NULL);
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static int block_size_init(void)
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{
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sysfs_create_file(&memory_sysdev_class.kset.kobj,
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&class_attr_block_size_bytes.attr);
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return 0;
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}
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/*
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* Some architectures will have custom drivers to do this, and
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* will not need to do it from userspace. The fake hot-add code
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* as well as ppc64 will do all of their discovery in userspace
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* and will require this interface.
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*/
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#ifdef CONFIG_ARCH_MEMORY_PROBE
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static ssize_t
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memory_probe_store(struct class *class, const char __user *buf, size_t count)
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{
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u64 phys_addr;
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int ret;
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phys_addr = simple_strtoull(buf, NULL, 0);
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ret = add_memory(phys_addr, PAGES_PER_SECTION << PAGE_SHIFT);
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if (ret)
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count = ret;
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return count;
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}
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static CLASS_ATTR(probe, 0700, NULL, memory_probe_store);
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static int memory_probe_init(void)
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{
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sysfs_create_file(&memory_sysdev_class.kset.kobj,
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&class_attr_probe.attr);
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return 0;
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}
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#else
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#define memory_probe_init(...) do {} while (0)
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#endif
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/*
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* Note that phys_device is optional. It is here to allow for
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* differentiation between which *physical* devices each
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* section belongs to...
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*/
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static int add_memory_block(unsigned long node_id, struct mem_section *section,
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unsigned long state, int phys_device)
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{
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size_t size = sizeof(struct memory_block);
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struct memory_block *mem = kmalloc(size, GFP_KERNEL);
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int ret = 0;
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if (!mem)
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return -ENOMEM;
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memset(mem, 0, size);
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mem->phys_index = __section_nr(section);
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mem->state = state;
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init_MUTEX(&mem->state_sem);
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mem->phys_device = phys_device;
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ret = register_memory(mem, section, NULL);
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if (!ret)
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ret = mem_create_simple_file(mem, phys_index);
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if (!ret)
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ret = mem_create_simple_file(mem, state);
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if (!ret)
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ret = mem_create_simple_file(mem, phys_device);
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return ret;
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}
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/*
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* For now, we have a linear search to go find the appropriate
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* memory_block corresponding to a particular phys_index. If
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* this gets to be a real problem, we can always use a radix
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* tree or something here.
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*
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* This could be made generic for all sysdev classes.
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*/
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static struct memory_block *find_memory_block(struct mem_section *section)
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{
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struct kobject *kobj;
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struct sys_device *sysdev;
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struct memory_block *mem;
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char name[sizeof(MEMORY_CLASS_NAME) + 9 + 1];
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/*
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* This only works because we know that section == sysdev->id
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* slightly redundant with sysdev_register()
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*/
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sprintf(&name[0], "%s%d", MEMORY_CLASS_NAME, __section_nr(section));
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kobj = kset_find_obj(&memory_sysdev_class.kset, name);
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if (!kobj)
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return NULL;
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sysdev = container_of(kobj, struct sys_device, kobj);
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mem = container_of(sysdev, struct memory_block, sysdev);
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return mem;
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}
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int remove_memory_block(unsigned long node_id, struct mem_section *section,
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int phys_device)
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{
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struct memory_block *mem;
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mem = find_memory_block(section);
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mem_remove_simple_file(mem, phys_index);
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mem_remove_simple_file(mem, state);
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mem_remove_simple_file(mem, phys_device);
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unregister_memory(mem, section, NULL);
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return 0;
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}
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/*
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* need an interface for the VM to add new memory regions,
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* but without onlining it.
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*/
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int register_new_memory(struct mem_section *section)
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{
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return add_memory_block(0, section, MEM_OFFLINE, 0);
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}
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int unregister_memory_section(struct mem_section *section)
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{
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if (!valid_section(section))
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return -EINVAL;
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return remove_memory_block(0, section, 0);
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}
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/*
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* Initialize the sysfs support for memory devices...
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*/
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int __init memory_dev_init(void)
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{
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unsigned int i;
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int ret;
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memory_sysdev_class.kset.hotplug_ops = &memory_hotplug_ops;
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ret = sysdev_class_register(&memory_sysdev_class);
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/*
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* Create entries for memory sections that were found
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* during boot and have been initialized
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*/
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for (i = 0; i < NR_MEM_SECTIONS; i++) {
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if (!valid_section_nr(i))
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continue;
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add_memory_block(0, __nr_to_section(i), MEM_ONLINE, 0);
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}
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memory_probe_init();
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block_size_init();
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return ret;
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}
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