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604 lines
14 KiB
604 lines
14 KiB
/*
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* linux/mm/memory_hotplug.c
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*
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* Copyright (C)
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*/
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#include <linux/stddef.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/interrupt.h>
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#include <linux/pagemap.h>
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#include <linux/bootmem.h>
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#include <linux/compiler.h>
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#include <linux/module.h>
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#include <linux/pagevec.h>
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#include <linux/writeback.h>
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#include <linux/slab.h>
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#include <linux/sysctl.h>
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#include <linux/cpu.h>
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#include <linux/memory.h>
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#include <linux/memory_hotplug.h>
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#include <linux/highmem.h>
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#include <linux/vmalloc.h>
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#include <linux/ioport.h>
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#include <linux/cpuset.h>
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#include <linux/delay.h>
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#include <linux/migrate.h>
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#include <linux/page-isolation.h>
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#include <asm/tlbflush.h>
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/* add this memory to iomem resource */
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static struct resource *register_memory_resource(u64 start, u64 size)
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{
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struct resource *res;
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res = kzalloc(sizeof(struct resource), GFP_KERNEL);
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BUG_ON(!res);
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res->name = "System RAM";
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res->start = start;
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res->end = start + size - 1;
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res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
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if (request_resource(&iomem_resource, res) < 0) {
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printk("System RAM resource %llx - %llx cannot be added\n",
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(unsigned long long)res->start, (unsigned long long)res->end);
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kfree(res);
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res = NULL;
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}
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return res;
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}
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static void release_memory_resource(struct resource *res)
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{
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if (!res)
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return;
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release_resource(res);
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kfree(res);
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return;
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}
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#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
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static int __add_zone(struct zone *zone, unsigned long phys_start_pfn)
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{
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struct pglist_data *pgdat = zone->zone_pgdat;
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int nr_pages = PAGES_PER_SECTION;
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int nid = pgdat->node_id;
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int zone_type;
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zone_type = zone - pgdat->node_zones;
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if (!zone->wait_table) {
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int ret = 0;
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ret = init_currently_empty_zone(zone, phys_start_pfn,
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nr_pages, MEMMAP_HOTPLUG);
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if (ret < 0)
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return ret;
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}
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memmap_init_zone(nr_pages, nid, zone_type,
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phys_start_pfn, MEMMAP_HOTPLUG);
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return 0;
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}
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static int __add_section(struct zone *zone, unsigned long phys_start_pfn)
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{
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int nr_pages = PAGES_PER_SECTION;
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int ret;
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if (pfn_valid(phys_start_pfn))
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return -EEXIST;
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ret = sparse_add_one_section(zone, phys_start_pfn, nr_pages);
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if (ret < 0)
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return ret;
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ret = __add_zone(zone, phys_start_pfn);
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if (ret < 0)
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return ret;
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return register_new_memory(__pfn_to_section(phys_start_pfn));
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}
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/*
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* Reasonably generic function for adding memory. It is
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* expected that archs that support memory hotplug will
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* call this function after deciding the zone to which to
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* add the new pages.
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*/
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int __add_pages(struct zone *zone, unsigned long phys_start_pfn,
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unsigned long nr_pages)
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{
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unsigned long i;
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int err = 0;
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int start_sec, end_sec;
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/* during initialize mem_map, align hot-added range to section */
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start_sec = pfn_to_section_nr(phys_start_pfn);
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end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
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for (i = start_sec; i <= end_sec; i++) {
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err = __add_section(zone, i << PFN_SECTION_SHIFT);
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/*
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* EEXIST is finally dealt with by ioresource collision
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* check. see add_memory() => register_memory_resource()
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* Warning will be printed if there is collision.
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*/
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if (err && (err != -EEXIST))
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break;
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err = 0;
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}
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return err;
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}
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EXPORT_SYMBOL_GPL(__add_pages);
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static void grow_zone_span(struct zone *zone,
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unsigned long start_pfn, unsigned long end_pfn)
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{
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unsigned long old_zone_end_pfn;
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zone_span_writelock(zone);
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old_zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
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if (start_pfn < zone->zone_start_pfn)
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zone->zone_start_pfn = start_pfn;
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zone->spanned_pages = max(old_zone_end_pfn, end_pfn) -
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zone->zone_start_pfn;
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zone_span_writeunlock(zone);
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}
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static void grow_pgdat_span(struct pglist_data *pgdat,
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unsigned long start_pfn, unsigned long end_pfn)
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{
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unsigned long old_pgdat_end_pfn =
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pgdat->node_start_pfn + pgdat->node_spanned_pages;
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if (start_pfn < pgdat->node_start_pfn)
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pgdat->node_start_pfn = start_pfn;
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pgdat->node_spanned_pages = max(old_pgdat_end_pfn, end_pfn) -
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pgdat->node_start_pfn;
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}
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static int online_pages_range(unsigned long start_pfn, unsigned long nr_pages,
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void *arg)
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{
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unsigned long i;
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unsigned long onlined_pages = *(unsigned long *)arg;
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struct page *page;
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if (PageReserved(pfn_to_page(start_pfn)))
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for (i = 0; i < nr_pages; i++) {
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page = pfn_to_page(start_pfn + i);
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online_page(page);
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onlined_pages++;
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}
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*(unsigned long *)arg = onlined_pages;
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return 0;
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}
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int online_pages(unsigned long pfn, unsigned long nr_pages)
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{
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unsigned long flags;
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unsigned long onlined_pages = 0;
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struct zone *zone;
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int need_zonelists_rebuild = 0;
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int nid;
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int ret;
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struct memory_notify arg;
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arg.start_pfn = pfn;
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arg.nr_pages = nr_pages;
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arg.status_change_nid = -1;
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nid = page_to_nid(pfn_to_page(pfn));
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if (node_present_pages(nid) == 0)
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arg.status_change_nid = nid;
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ret = memory_notify(MEM_GOING_ONLINE, &arg);
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ret = notifier_to_errno(ret);
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if (ret) {
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memory_notify(MEM_CANCEL_ONLINE, &arg);
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return ret;
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}
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/*
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* This doesn't need a lock to do pfn_to_page().
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* The section can't be removed here because of the
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* memory_block->state_sem.
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*/
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zone = page_zone(pfn_to_page(pfn));
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pgdat_resize_lock(zone->zone_pgdat, &flags);
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grow_zone_span(zone, pfn, pfn + nr_pages);
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grow_pgdat_span(zone->zone_pgdat, pfn, pfn + nr_pages);
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pgdat_resize_unlock(zone->zone_pgdat, &flags);
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/*
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* If this zone is not populated, then it is not in zonelist.
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* This means the page allocator ignores this zone.
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* So, zonelist must be updated after online.
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*/
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if (!populated_zone(zone))
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need_zonelists_rebuild = 1;
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walk_memory_resource(pfn, nr_pages, &onlined_pages,
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online_pages_range);
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zone->present_pages += onlined_pages;
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zone->zone_pgdat->node_present_pages += onlined_pages;
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setup_per_zone_pages_min();
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if (onlined_pages) {
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kswapd_run(zone_to_nid(zone));
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node_set_state(zone_to_nid(zone), N_HIGH_MEMORY);
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}
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if (need_zonelists_rebuild)
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build_all_zonelists();
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vm_total_pages = nr_free_pagecache_pages();
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writeback_set_ratelimit();
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if (onlined_pages)
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memory_notify(MEM_ONLINE, &arg);
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return 0;
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}
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#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
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static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
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{
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struct pglist_data *pgdat;
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unsigned long zones_size[MAX_NR_ZONES] = {0};
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unsigned long zholes_size[MAX_NR_ZONES] = {0};
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unsigned long start_pfn = start >> PAGE_SHIFT;
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pgdat = arch_alloc_nodedata(nid);
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if (!pgdat)
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return NULL;
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arch_refresh_nodedata(nid, pgdat);
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/* we can use NODE_DATA(nid) from here */
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/* init node's zones as empty zones, we don't have any present pages.*/
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free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
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return pgdat;
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}
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static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
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{
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arch_refresh_nodedata(nid, NULL);
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arch_free_nodedata(pgdat);
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return;
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}
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int add_memory(int nid, u64 start, u64 size)
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{
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pg_data_t *pgdat = NULL;
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int new_pgdat = 0;
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struct resource *res;
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int ret;
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res = register_memory_resource(start, size);
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if (!res)
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return -EEXIST;
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if (!node_online(nid)) {
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pgdat = hotadd_new_pgdat(nid, start);
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if (!pgdat)
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return -ENOMEM;
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new_pgdat = 1;
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}
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/* call arch's memory hotadd */
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ret = arch_add_memory(nid, start, size);
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if (ret < 0)
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goto error;
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/* we online node here. we can't roll back from here. */
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node_set_online(nid);
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cpuset_track_online_nodes();
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if (new_pgdat) {
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ret = register_one_node(nid);
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/*
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* If sysfs file of new node can't create, cpu on the node
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* can't be hot-added. There is no rollback way now.
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* So, check by BUG_ON() to catch it reluctantly..
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*/
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BUG_ON(ret);
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}
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return ret;
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error:
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/* rollback pgdat allocation and others */
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if (new_pgdat)
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rollback_node_hotadd(nid, pgdat);
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if (res)
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release_memory_resource(res);
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return ret;
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}
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EXPORT_SYMBOL_GPL(add_memory);
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#ifdef CONFIG_MEMORY_HOTREMOVE
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/*
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* Confirm all pages in a range [start, end) is belongs to the same zone.
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*/
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static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn)
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{
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unsigned long pfn;
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struct zone *zone = NULL;
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struct page *page;
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int i;
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for (pfn = start_pfn;
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pfn < end_pfn;
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pfn += MAX_ORDER_NR_PAGES) {
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i = 0;
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/* This is just a CONFIG_HOLES_IN_ZONE check.*/
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while ((i < MAX_ORDER_NR_PAGES) && !pfn_valid_within(pfn + i))
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i++;
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if (i == MAX_ORDER_NR_PAGES)
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continue;
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page = pfn_to_page(pfn + i);
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if (zone && page_zone(page) != zone)
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return 0;
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zone = page_zone(page);
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}
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return 1;
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}
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/*
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* Scanning pfn is much easier than scanning lru list.
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* Scan pfn from start to end and Find LRU page.
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*/
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int scan_lru_pages(unsigned long start, unsigned long end)
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{
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unsigned long pfn;
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struct page *page;
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for (pfn = start; pfn < end; pfn++) {
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if (pfn_valid(pfn)) {
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page = pfn_to_page(pfn);
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if (PageLRU(page))
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return pfn;
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}
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}
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return 0;
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}
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static struct page *
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hotremove_migrate_alloc(struct page *page,
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unsigned long private,
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int **x)
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{
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/* This should be improoooooved!! */
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return alloc_page(GFP_HIGHUSER_PAGECACHE);
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}
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#define NR_OFFLINE_AT_ONCE_PAGES (256)
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static int
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do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
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{
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unsigned long pfn;
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struct page *page;
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int move_pages = NR_OFFLINE_AT_ONCE_PAGES;
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int not_managed = 0;
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int ret = 0;
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LIST_HEAD(source);
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for (pfn = start_pfn; pfn < end_pfn && move_pages > 0; pfn++) {
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if (!pfn_valid(pfn))
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continue;
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page = pfn_to_page(pfn);
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if (!page_count(page))
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continue;
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/*
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* We can skip free pages. And we can only deal with pages on
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* LRU.
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*/
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ret = isolate_lru_page(page, &source);
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if (!ret) { /* Success */
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move_pages--;
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} else {
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/* Becasue we don't have big zone->lock. we should
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check this again here. */
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if (page_count(page))
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not_managed++;
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#ifdef CONFIG_DEBUG_VM
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printk(KERN_INFO "removing from LRU failed"
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" %lx/%d/%lx\n",
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pfn, page_count(page), page->flags);
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#endif
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}
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}
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ret = -EBUSY;
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if (not_managed) {
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if (!list_empty(&source))
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putback_lru_pages(&source);
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goto out;
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}
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ret = 0;
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if (list_empty(&source))
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goto out;
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/* this function returns # of failed pages */
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ret = migrate_pages(&source, hotremove_migrate_alloc, 0);
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out:
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return ret;
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}
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/*
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* remove from free_area[] and mark all as Reserved.
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*/
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static int
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offline_isolated_pages_cb(unsigned long start, unsigned long nr_pages,
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void *data)
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{
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__offline_isolated_pages(start, start + nr_pages);
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return 0;
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}
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static void
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offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn)
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{
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walk_memory_resource(start_pfn, end_pfn - start_pfn, NULL,
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offline_isolated_pages_cb);
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}
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/*
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* Check all pages in range, recoreded as memory resource, are isolated.
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*/
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static int
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check_pages_isolated_cb(unsigned long start_pfn, unsigned long nr_pages,
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void *data)
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{
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int ret;
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long offlined = *(long *)data;
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ret = test_pages_isolated(start_pfn, start_pfn + nr_pages);
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offlined = nr_pages;
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if (!ret)
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*(long *)data += offlined;
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return ret;
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}
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static long
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check_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
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{
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long offlined = 0;
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int ret;
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ret = walk_memory_resource(start_pfn, end_pfn - start_pfn, &offlined,
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check_pages_isolated_cb);
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if (ret < 0)
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offlined = (long)ret;
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return offlined;
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}
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int offline_pages(unsigned long start_pfn,
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unsigned long end_pfn, unsigned long timeout)
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{
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unsigned long pfn, nr_pages, expire;
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long offlined_pages;
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int ret, drain, retry_max, node;
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struct zone *zone;
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struct memory_notify arg;
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BUG_ON(start_pfn >= end_pfn);
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/* at least, alignment against pageblock is necessary */
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if (!IS_ALIGNED(start_pfn, pageblock_nr_pages))
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return -EINVAL;
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if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
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return -EINVAL;
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/* This makes hotplug much easier...and readable.
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we assume this for now. .*/
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if (!test_pages_in_a_zone(start_pfn, end_pfn))
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return -EINVAL;
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zone = page_zone(pfn_to_page(start_pfn));
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node = zone_to_nid(zone);
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nr_pages = end_pfn - start_pfn;
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/* set above range as isolated */
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ret = start_isolate_page_range(start_pfn, end_pfn);
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if (ret)
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return ret;
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arg.start_pfn = start_pfn;
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arg.nr_pages = nr_pages;
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arg.status_change_nid = -1;
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if (nr_pages >= node_present_pages(node))
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arg.status_change_nid = node;
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ret = memory_notify(MEM_GOING_OFFLINE, &arg);
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ret = notifier_to_errno(ret);
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if (ret)
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goto failed_removal;
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pfn = start_pfn;
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expire = jiffies + timeout;
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drain = 0;
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retry_max = 5;
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repeat:
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/* start memory hot removal */
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ret = -EAGAIN;
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|
if (time_after(jiffies, expire))
|
|
goto failed_removal;
|
|
ret = -EINTR;
|
|
if (signal_pending(current))
|
|
goto failed_removal;
|
|
ret = 0;
|
|
if (drain) {
|
|
lru_add_drain_all();
|
|
flush_scheduled_work();
|
|
cond_resched();
|
|
drain_all_pages();
|
|
}
|
|
|
|
pfn = scan_lru_pages(start_pfn, end_pfn);
|
|
if (pfn) { /* We have page on LRU */
|
|
ret = do_migrate_range(pfn, end_pfn);
|
|
if (!ret) {
|
|
drain = 1;
|
|
goto repeat;
|
|
} else {
|
|
if (ret < 0)
|
|
if (--retry_max == 0)
|
|
goto failed_removal;
|
|
yield();
|
|
drain = 1;
|
|
goto repeat;
|
|
}
|
|
}
|
|
/* drain all zone's lru pagevec, this is asyncronous... */
|
|
lru_add_drain_all();
|
|
flush_scheduled_work();
|
|
yield();
|
|
/* drain pcp pages , this is synchrouns. */
|
|
drain_all_pages();
|
|
/* check again */
|
|
offlined_pages = check_pages_isolated(start_pfn, end_pfn);
|
|
if (offlined_pages < 0) {
|
|
ret = -EBUSY;
|
|
goto failed_removal;
|
|
}
|
|
printk(KERN_INFO "Offlined Pages %ld\n", offlined_pages);
|
|
/* Ok, all of our target is islaoted.
|
|
We cannot do rollback at this point. */
|
|
offline_isolated_pages(start_pfn, end_pfn);
|
|
/* reset pagetype flags and makes migrate type to be MOVABLE */
|
|
undo_isolate_page_range(start_pfn, end_pfn);
|
|
/* removal success */
|
|
zone->present_pages -= offlined_pages;
|
|
zone->zone_pgdat->node_present_pages -= offlined_pages;
|
|
totalram_pages -= offlined_pages;
|
|
num_physpages -= offlined_pages;
|
|
|
|
vm_total_pages = nr_free_pagecache_pages();
|
|
writeback_set_ratelimit();
|
|
|
|
memory_notify(MEM_OFFLINE, &arg);
|
|
return 0;
|
|
|
|
failed_removal:
|
|
printk(KERN_INFO "memory offlining %lx to %lx failed\n",
|
|
start_pfn, end_pfn);
|
|
memory_notify(MEM_CANCEL_OFFLINE, &arg);
|
|
/* pushback to free area */
|
|
undo_isolate_page_range(start_pfn, end_pfn);
|
|
|
|
return ret;
|
|
}
|
|
#else
|
|
int remove_memory(u64 start, u64 size)
|
|
{
|
|
return -EINVAL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(remove_memory);
|
|
#endif /* CONFIG_MEMORY_HOTREMOVE */
|
|
|