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-rw-r--r--mm/memory_hotplug.c2373
1 files changed, 2373 insertions, 0 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
new file mode 100644
index 000000000..f36525a59
--- /dev/null
+++ b/mm/memory_hotplug.c
@@ -0,0 +1,2373 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/mm/memory_hotplug.c
+ *
+ * Copyright (C)
+ */
+
+#include <linux/stddef.h>
+#include <linux/mm.h>
+#include <linux/sched/signal.h>
+#include <linux/swap.h>
+#include <linux/interrupt.h>
+#include <linux/pagemap.h>
+#include <linux/compiler.h>
+#include <linux/export.h>
+#include <linux/writeback.h>
+#include <linux/slab.h>
+#include <linux/sysctl.h>
+#include <linux/cpu.h>
+#include <linux/memory.h>
+#include <linux/memremap.h>
+#include <linux/memory_hotplug.h>
+#include <linux/vmalloc.h>
+#include <linux/ioport.h>
+#include <linux/delay.h>
+#include <linux/migrate.h>
+#include <linux/page-isolation.h>
+#include <linux/pfn.h>
+#include <linux/suspend.h>
+#include <linux/mm_inline.h>
+#include <linux/firmware-map.h>
+#include <linux/stop_machine.h>
+#include <linux/hugetlb.h>
+#include <linux/memblock.h>
+#include <linux/compaction.h>
+#include <linux/rmap.h>
+#include <linux/module.h>
+
+#include <asm/tlbflush.h>
+
+#include "internal.h"
+#include "shuffle.h"
+
+enum {
+ MEMMAP_ON_MEMORY_DISABLE = 0,
+ MEMMAP_ON_MEMORY_ENABLE,
+ MEMMAP_ON_MEMORY_FORCE,
+};
+
+static int memmap_mode __read_mostly = MEMMAP_ON_MEMORY_DISABLE;
+
+static inline unsigned long memory_block_memmap_size(void)
+{
+ return PHYS_PFN(memory_block_size_bytes()) * sizeof(struct page);
+}
+
+static inline unsigned long memory_block_memmap_on_memory_pages(void)
+{
+ unsigned long nr_pages = PFN_UP(memory_block_memmap_size());
+
+ /*
+ * In "forced" memmap_on_memory mode, we add extra pages to align the
+ * vmemmap size to cover full pageblocks. That way, we can add memory
+ * even if the vmemmap size is not properly aligned, however, we might waste
+ * memory.
+ */
+ if (memmap_mode == MEMMAP_ON_MEMORY_FORCE)
+ return pageblock_align(nr_pages);
+ return nr_pages;
+}
+
+#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY
+/*
+ * memory_hotplug.memmap_on_memory parameter
+ */
+static int set_memmap_mode(const char *val, const struct kernel_param *kp)
+{
+ int ret, mode;
+ bool enabled;
+
+ if (sysfs_streq(val, "force") || sysfs_streq(val, "FORCE")) {
+ mode = MEMMAP_ON_MEMORY_FORCE;
+ } else {
+ ret = kstrtobool(val, &enabled);
+ if (ret < 0)
+ return ret;
+ if (enabled)
+ mode = MEMMAP_ON_MEMORY_ENABLE;
+ else
+ mode = MEMMAP_ON_MEMORY_DISABLE;
+ }
+ *((int *)kp->arg) = mode;
+ if (mode == MEMMAP_ON_MEMORY_FORCE) {
+ unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
+
+ pr_info_once("Memory hotplug will waste %ld pages in each memory block\n",
+ memmap_pages - PFN_UP(memory_block_memmap_size()));
+ }
+ return 0;
+}
+
+static int get_memmap_mode(char *buffer, const struct kernel_param *kp)
+{
+ int mode = *((int *)kp->arg);
+
+ if (mode == MEMMAP_ON_MEMORY_FORCE)
+ return sprintf(buffer, "force\n");
+ return sprintf(buffer, "%c\n", mode ? 'Y' : 'N');
+}
+
+static const struct kernel_param_ops memmap_mode_ops = {
+ .set = set_memmap_mode,
+ .get = get_memmap_mode,
+};
+module_param_cb(memmap_on_memory, &memmap_mode_ops, &memmap_mode, 0444);
+MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug\n"
+ "With value \"force\" it could result in memory wastage due "
+ "to memmap size limitations (Y/N/force)");
+
+static inline bool mhp_memmap_on_memory(void)
+{
+ return memmap_mode != MEMMAP_ON_MEMORY_DISABLE;
+}
+#else
+static inline bool mhp_memmap_on_memory(void)
+{
+ return false;
+}
+#endif
+
+enum {
+ ONLINE_POLICY_CONTIG_ZONES = 0,
+ ONLINE_POLICY_AUTO_MOVABLE,
+};
+
+static const char * const online_policy_to_str[] = {
+ [ONLINE_POLICY_CONTIG_ZONES] = "contig-zones",
+ [ONLINE_POLICY_AUTO_MOVABLE] = "auto-movable",
+};
+
+static int set_online_policy(const char *val, const struct kernel_param *kp)
+{
+ int ret = sysfs_match_string(online_policy_to_str, val);
+
+ if (ret < 0)
+ return ret;
+ *((int *)kp->arg) = ret;
+ return 0;
+}
+
+static int get_online_policy(char *buffer, const struct kernel_param *kp)
+{
+ return sprintf(buffer, "%s\n", online_policy_to_str[*((int *)kp->arg)]);
+}
+
+/*
+ * memory_hotplug.online_policy: configure online behavior when onlining without
+ * specifying a zone (MMOP_ONLINE)
+ *
+ * "contig-zones": keep zone contiguous
+ * "auto-movable": online memory to ZONE_MOVABLE if the configuration
+ * (auto_movable_ratio, auto_movable_numa_aware) allows for it
+ */
+static int online_policy __read_mostly = ONLINE_POLICY_CONTIG_ZONES;
+static const struct kernel_param_ops online_policy_ops = {
+ .set = set_online_policy,
+ .get = get_online_policy,
+};
+module_param_cb(online_policy, &online_policy_ops, &online_policy, 0644);
+MODULE_PARM_DESC(online_policy,
+ "Set the online policy (\"contig-zones\", \"auto-movable\") "
+ "Default: \"contig-zones\"");
+
+/*
+ * memory_hotplug.auto_movable_ratio: specify maximum MOVABLE:KERNEL ratio
+ *
+ * The ratio represent an upper limit and the kernel might decide to not
+ * online some memory to ZONE_MOVABLE -- e.g., because hotplugged KERNEL memory
+ * doesn't allow for more MOVABLE memory.
+ */
+static unsigned int auto_movable_ratio __read_mostly = 301;
+module_param(auto_movable_ratio, uint, 0644);
+MODULE_PARM_DESC(auto_movable_ratio,
+ "Set the maximum ratio of MOVABLE:KERNEL memory in the system "
+ "in percent for \"auto-movable\" online policy. Default: 301");
+
+/*
+ * memory_hotplug.auto_movable_numa_aware: consider numa node stats
+ */
+#ifdef CONFIG_NUMA
+static bool auto_movable_numa_aware __read_mostly = true;
+module_param(auto_movable_numa_aware, bool, 0644);
+MODULE_PARM_DESC(auto_movable_numa_aware,
+ "Consider numa node stats in addition to global stats in "
+ "\"auto-movable\" online policy. Default: true");
+#endif /* CONFIG_NUMA */
+
+/*
+ * online_page_callback contains pointer to current page onlining function.
+ * Initially it is generic_online_page(). If it is required it could be
+ * changed by calling set_online_page_callback() for callback registration
+ * and restore_online_page_callback() for generic callback restore.
+ */
+
+static online_page_callback_t online_page_callback = generic_online_page;
+static DEFINE_MUTEX(online_page_callback_lock);
+
+DEFINE_STATIC_PERCPU_RWSEM(mem_hotplug_lock);
+
+void get_online_mems(void)
+{
+ percpu_down_read(&mem_hotplug_lock);
+}
+
+void put_online_mems(void)
+{
+ percpu_up_read(&mem_hotplug_lock);
+}
+
+bool movable_node_enabled = false;
+
+#ifndef CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE
+int mhp_default_online_type = MMOP_OFFLINE;
+#else
+int mhp_default_online_type = MMOP_ONLINE;
+#endif
+
+static int __init setup_memhp_default_state(char *str)
+{
+ const int online_type = mhp_online_type_from_str(str);
+
+ if (online_type >= 0)
+ mhp_default_online_type = online_type;
+
+ return 1;
+}
+__setup("memhp_default_state=", setup_memhp_default_state);
+
+void mem_hotplug_begin(void)
+{
+ cpus_read_lock();
+ percpu_down_write(&mem_hotplug_lock);
+}
+
+void mem_hotplug_done(void)
+{
+ percpu_up_write(&mem_hotplug_lock);
+ cpus_read_unlock();
+}
+
+u64 max_mem_size = U64_MAX;
+
+/* add this memory to iomem resource */
+static struct resource *register_memory_resource(u64 start, u64 size,
+ const char *resource_name)
+{
+ struct resource *res;
+ unsigned long flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+
+ if (strcmp(resource_name, "System RAM"))
+ flags |= IORESOURCE_SYSRAM_DRIVER_MANAGED;
+
+ if (!mhp_range_allowed(start, size, true))
+ return ERR_PTR(-E2BIG);
+
+ /*
+ * Make sure value parsed from 'mem=' only restricts memory adding
+ * while booting, so that memory hotplug won't be impacted. Please
+ * refer to document of 'mem=' in kernel-parameters.txt for more
+ * details.
+ */
+ if (start + size > max_mem_size && system_state < SYSTEM_RUNNING)
+ return ERR_PTR(-E2BIG);
+
+ /*
+ * Request ownership of the new memory range. This might be
+ * a child of an existing resource that was present but
+ * not marked as busy.
+ */
+ res = __request_region(&iomem_resource, start, size,
+ resource_name, flags);
+
+ if (!res) {
+ pr_debug("Unable to reserve System RAM region: %016llx->%016llx\n",
+ start, start + size);
+ return ERR_PTR(-EEXIST);
+ }
+ return res;
+}
+
+static void release_memory_resource(struct resource *res)
+{
+ if (!res)
+ return;
+ release_resource(res);
+ kfree(res);
+}
+
+static int check_pfn_span(unsigned long pfn, unsigned long nr_pages)
+{
+ /*
+ * Disallow all operations smaller than a sub-section and only
+ * allow operations smaller than a section for
+ * SPARSEMEM_VMEMMAP. Note that check_hotplug_memory_range()
+ * enforces a larger memory_block_size_bytes() granularity for
+ * memory that will be marked online, so this check should only
+ * fire for direct arch_{add,remove}_memory() users outside of
+ * add_memory_resource().
+ */
+ unsigned long min_align;
+
+ if (IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
+ min_align = PAGES_PER_SUBSECTION;
+ else
+ min_align = PAGES_PER_SECTION;
+ if (!IS_ALIGNED(pfn | nr_pages, min_align))
+ return -EINVAL;
+ return 0;
+}
+
+/*
+ * Return page for the valid pfn only if the page is online. All pfn
+ * walkers which rely on the fully initialized page->flags and others
+ * should use this rather than pfn_valid && pfn_to_page
+ */
+struct page *pfn_to_online_page(unsigned long pfn)
+{
+ unsigned long nr = pfn_to_section_nr(pfn);
+ struct dev_pagemap *pgmap;
+ struct mem_section *ms;
+
+ if (nr >= NR_MEM_SECTIONS)
+ return NULL;
+
+ ms = __nr_to_section(nr);
+ if (!online_section(ms))
+ return NULL;
+
+ /*
+ * Save some code text when online_section() +
+ * pfn_section_valid() are sufficient.
+ */
+ if (IS_ENABLED(CONFIG_HAVE_ARCH_PFN_VALID) && !pfn_valid(pfn))
+ return NULL;
+
+ if (!pfn_section_valid(ms, pfn))
+ return NULL;
+
+ if (!online_device_section(ms))
+ return pfn_to_page(pfn);
+
+ /*
+ * Slowpath: when ZONE_DEVICE collides with
+ * ZONE_{NORMAL,MOVABLE} within the same section some pfns in
+ * the section may be 'offline' but 'valid'. Only
+ * get_dev_pagemap() can determine sub-section online status.
+ */
+ pgmap = get_dev_pagemap(pfn, NULL);
+ put_dev_pagemap(pgmap);
+
+ /* The presence of a pgmap indicates ZONE_DEVICE offline pfn */
+ if (pgmap)
+ return NULL;
+
+ return pfn_to_page(pfn);
+}
+EXPORT_SYMBOL_GPL(pfn_to_online_page);
+
+int __ref __add_pages(int nid, unsigned long pfn, unsigned long nr_pages,
+ struct mhp_params *params)
+{
+ const unsigned long end_pfn = pfn + nr_pages;
+ unsigned long cur_nr_pages;
+ int err;
+ struct vmem_altmap *altmap = params->altmap;
+
+ if (WARN_ON_ONCE(!pgprot_val(params->pgprot)))
+ return -EINVAL;
+
+ VM_BUG_ON(!mhp_range_allowed(PFN_PHYS(pfn), nr_pages * PAGE_SIZE, false));
+
+ if (altmap) {
+ /*
+ * Validate altmap is within bounds of the total request
+ */
+ if (altmap->base_pfn != pfn
+ || vmem_altmap_offset(altmap) > nr_pages) {
+ pr_warn_once("memory add fail, invalid altmap\n");
+ return -EINVAL;
+ }
+ altmap->alloc = 0;
+ }
+
+ if (check_pfn_span(pfn, nr_pages)) {
+ WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
+ return -EINVAL;
+ }
+
+ for (; pfn < end_pfn; pfn += cur_nr_pages) {
+ /* Select all remaining pages up to the next section boundary */
+ cur_nr_pages = min(end_pfn - pfn,
+ SECTION_ALIGN_UP(pfn + 1) - pfn);
+ err = sparse_add_section(nid, pfn, cur_nr_pages, altmap,
+ params->pgmap);
+ if (err)
+ break;
+ cond_resched();
+ }
+ vmemmap_populate_print_last();
+ return err;
+}
+
+/* find the smallest valid pfn in the range [start_pfn, end_pfn) */
+static unsigned long find_smallest_section_pfn(int nid, struct zone *zone,
+ unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ for (; start_pfn < end_pfn; start_pfn += PAGES_PER_SUBSECTION) {
+ if (unlikely(!pfn_to_online_page(start_pfn)))
+ continue;
+
+ if (unlikely(pfn_to_nid(start_pfn) != nid))
+ continue;
+
+ if (zone != page_zone(pfn_to_page(start_pfn)))
+ continue;
+
+ return start_pfn;
+ }
+
+ return 0;
+}
+
+/* find the biggest valid pfn in the range [start_pfn, end_pfn). */
+static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
+ unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ unsigned long pfn;
+
+ /* pfn is the end pfn of a memory section. */
+ pfn = end_pfn - 1;
+ for (; pfn >= start_pfn; pfn -= PAGES_PER_SUBSECTION) {
+ if (unlikely(!pfn_to_online_page(pfn)))
+ continue;
+
+ if (unlikely(pfn_to_nid(pfn) != nid))
+ continue;
+
+ if (zone != page_zone(pfn_to_page(pfn)))
+ continue;
+
+ return pfn;
+ }
+
+ return 0;
+}
+
+static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
+ unsigned long end_pfn)
+{
+ unsigned long pfn;
+ int nid = zone_to_nid(zone);
+
+ if (zone->zone_start_pfn == start_pfn) {
+ /*
+ * If the section is smallest section in the zone, it need
+ * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
+ * In this case, we find second smallest valid mem_section
+ * for shrinking zone.
+ */
+ pfn = find_smallest_section_pfn(nid, zone, end_pfn,
+ zone_end_pfn(zone));
+ if (pfn) {
+ zone->spanned_pages = zone_end_pfn(zone) - pfn;
+ zone->zone_start_pfn = pfn;
+ } else {
+ zone->zone_start_pfn = 0;
+ zone->spanned_pages = 0;
+ }
+ } else if (zone_end_pfn(zone) == end_pfn) {
+ /*
+ * If the section is biggest section in the zone, it need
+ * shrink zone->spanned_pages.
+ * In this case, we find second biggest valid mem_section for
+ * shrinking zone.
+ */
+ pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
+ start_pfn);
+ if (pfn)
+ zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
+ else {
+ zone->zone_start_pfn = 0;
+ zone->spanned_pages = 0;
+ }
+ }
+}
+
+static void update_pgdat_span(struct pglist_data *pgdat)
+{
+ unsigned long node_start_pfn = 0, node_end_pfn = 0;
+ struct zone *zone;
+
+ for (zone = pgdat->node_zones;
+ zone < pgdat->node_zones + MAX_NR_ZONES; zone++) {
+ unsigned long end_pfn = zone_end_pfn(zone);
+
+ /* No need to lock the zones, they can't change. */
+ if (!zone->spanned_pages)
+ continue;
+ if (!node_end_pfn) {
+ node_start_pfn = zone->zone_start_pfn;
+ node_end_pfn = end_pfn;
+ continue;
+ }
+
+ if (end_pfn > node_end_pfn)
+ node_end_pfn = end_pfn;
+ if (zone->zone_start_pfn < node_start_pfn)
+ node_start_pfn = zone->zone_start_pfn;
+ }
+
+ pgdat->node_start_pfn = node_start_pfn;
+ pgdat->node_spanned_pages = node_end_pfn - node_start_pfn;
+}
+
+void __ref remove_pfn_range_from_zone(struct zone *zone,
+ unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ const unsigned long end_pfn = start_pfn + nr_pages;
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ unsigned long pfn, cur_nr_pages;
+
+ /* Poison struct pages because they are now uninitialized again. */
+ for (pfn = start_pfn; pfn < end_pfn; pfn += cur_nr_pages) {
+ cond_resched();
+
+ /* Select all remaining pages up to the next section boundary */
+ cur_nr_pages =
+ min(end_pfn - pfn, SECTION_ALIGN_UP(pfn + 1) - pfn);
+ page_init_poison(pfn_to_page(pfn),
+ sizeof(struct page) * cur_nr_pages);
+ }
+
+ /*
+ * Zone shrinking code cannot properly deal with ZONE_DEVICE. So
+ * we will not try to shrink the zones - which is okay as
+ * set_zone_contiguous() cannot deal with ZONE_DEVICE either way.
+ */
+ if (zone_is_zone_device(zone))
+ return;
+
+ clear_zone_contiguous(zone);
+
+ shrink_zone_span(zone, start_pfn, start_pfn + nr_pages);
+ update_pgdat_span(pgdat);
+
+ set_zone_contiguous(zone);
+}
+
+/**
+ * __remove_pages() - remove sections of pages
+ * @pfn: starting pageframe (must be aligned to start of a section)
+ * @nr_pages: number of pages to remove (must be multiple of section size)
+ * @altmap: alternative device page map or %NULL if default memmap is used
+ *
+ * Generic helper function to remove section mappings and sysfs entries
+ * for the section of the memory we are removing. Caller needs to make
+ * sure that pages are marked reserved and zones are adjust properly by
+ * calling offline_pages().
+ */
+void __remove_pages(unsigned long pfn, unsigned long nr_pages,
+ struct vmem_altmap *altmap)
+{
+ const unsigned long end_pfn = pfn + nr_pages;
+ unsigned long cur_nr_pages;
+
+ if (check_pfn_span(pfn, nr_pages)) {
+ WARN(1, "Misaligned %s start: %#lx end: %#lx\n", __func__, pfn, pfn + nr_pages - 1);
+ return;
+ }
+
+ for (; pfn < end_pfn; pfn += cur_nr_pages) {
+ cond_resched();
+ /* Select all remaining pages up to the next section boundary */
+ cur_nr_pages = min(end_pfn - pfn,
+ SECTION_ALIGN_UP(pfn + 1) - pfn);
+ sparse_remove_section(pfn, cur_nr_pages, altmap);
+ }
+}
+
+int set_online_page_callback(online_page_callback_t callback)
+{
+ int rc = -EINVAL;
+
+ get_online_mems();
+ mutex_lock(&online_page_callback_lock);
+
+ if (online_page_callback == generic_online_page) {
+ online_page_callback = callback;
+ rc = 0;
+ }
+
+ mutex_unlock(&online_page_callback_lock);
+ put_online_mems();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(set_online_page_callback);
+
+int restore_online_page_callback(online_page_callback_t callback)
+{
+ int rc = -EINVAL;
+
+ get_online_mems();
+ mutex_lock(&online_page_callback_lock);
+
+ if (online_page_callback == callback) {
+ online_page_callback = generic_online_page;
+ rc = 0;
+ }
+
+ mutex_unlock(&online_page_callback_lock);
+ put_online_mems();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(restore_online_page_callback);
+
+void generic_online_page(struct page *page, unsigned int order)
+{
+ /*
+ * Freeing the page with debug_pagealloc enabled will try to unmap it,
+ * so we should map it first. This is better than introducing a special
+ * case in page freeing fast path.
+ */
+ debug_pagealloc_map_pages(page, 1 << order);
+ __free_pages_core(page, order);
+ totalram_pages_add(1UL << order);
+}
+EXPORT_SYMBOL_GPL(generic_online_page);
+
+static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
+{
+ const unsigned long end_pfn = start_pfn + nr_pages;
+ unsigned long pfn;
+
+ /*
+ * Online the pages in MAX_ORDER aligned chunks. The callback might
+ * decide to not expose all pages to the buddy (e.g., expose them
+ * later). We account all pages as being online and belonging to this
+ * zone ("present").
+ * When using memmap_on_memory, the range might not be aligned to
+ * MAX_ORDER_NR_PAGES - 1, but pageblock aligned. __ffs() will detect
+ * this and the first chunk to online will be pageblock_nr_pages.
+ */
+ for (pfn = start_pfn; pfn < end_pfn;) {
+ int order;
+
+ /*
+ * Free to online pages in the largest chunks alignment allows.
+ *
+ * __ffs() behaviour is undefined for 0. start == 0 is
+ * MAX_ORDER-aligned, Set order to MAX_ORDER for the case.
+ */
+ if (pfn)
+ order = min_t(int, MAX_ORDER, __ffs(pfn));
+ else
+ order = MAX_ORDER;
+
+ (*online_page_callback)(pfn_to_page(pfn), order);
+ pfn += (1UL << order);
+ }
+
+ /* mark all involved sections as online */
+ online_mem_sections(start_pfn, end_pfn);
+}
+
+/* check which state of node_states will be changed when online memory */
+static void node_states_check_changes_online(unsigned long nr_pages,
+ struct zone *zone, struct memory_notify *arg)
+{
+ int nid = zone_to_nid(zone);
+
+ arg->status_change_nid = NUMA_NO_NODE;
+ arg->status_change_nid_normal = NUMA_NO_NODE;
+
+ if (!node_state(nid, N_MEMORY))
+ arg->status_change_nid = nid;
+ if (zone_idx(zone) <= ZONE_NORMAL && !node_state(nid, N_NORMAL_MEMORY))
+ arg->status_change_nid_normal = nid;
+}
+
+static void node_states_set_node(int node, struct memory_notify *arg)
+{
+ if (arg->status_change_nid_normal >= 0)
+ node_set_state(node, N_NORMAL_MEMORY);
+
+ if (arg->status_change_nid >= 0)
+ node_set_state(node, N_MEMORY);
+}
+
+static void __meminit resize_zone_range(struct zone *zone, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long old_end_pfn = zone_end_pfn(zone);
+
+ if (zone_is_empty(zone) || start_pfn < zone->zone_start_pfn)
+ zone->zone_start_pfn = start_pfn;
+
+ zone->spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - zone->zone_start_pfn;
+}
+
+static void __meminit resize_pgdat_range(struct pglist_data *pgdat, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ unsigned long old_end_pfn = pgdat_end_pfn(pgdat);
+
+ if (!pgdat->node_spanned_pages || start_pfn < pgdat->node_start_pfn)
+ pgdat->node_start_pfn = start_pfn;
+
+ pgdat->node_spanned_pages = max(start_pfn + nr_pages, old_end_pfn) - pgdat->node_start_pfn;
+
+}
+
+#ifdef CONFIG_ZONE_DEVICE
+static void section_taint_zone_device(unsigned long pfn)
+{
+ struct mem_section *ms = __pfn_to_section(pfn);
+
+ ms->section_mem_map |= SECTION_TAINT_ZONE_DEVICE;
+}
+#else
+static inline void section_taint_zone_device(unsigned long pfn)
+{
+}
+#endif
+
+/*
+ * Associate the pfn range with the given zone, initializing the memmaps
+ * and resizing the pgdat/zone data to span the added pages. After this
+ * call, all affected pages are PG_reserved.
+ *
+ * All aligned pageblocks are initialized to the specified migratetype
+ * (usually MIGRATE_MOVABLE). Besides setting the migratetype, no related
+ * zone stats (e.g., nr_isolate_pageblock) are touched.
+ */
+void __ref move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
+ unsigned long nr_pages,
+ struct vmem_altmap *altmap, int migratetype)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ int nid = pgdat->node_id;
+
+ clear_zone_contiguous(zone);
+
+ if (zone_is_empty(zone))
+ init_currently_empty_zone(zone, start_pfn, nr_pages);
+ resize_zone_range(zone, start_pfn, nr_pages);
+ resize_pgdat_range(pgdat, start_pfn, nr_pages);
+
+ /*
+ * Subsection population requires care in pfn_to_online_page().
+ * Set the taint to enable the slow path detection of
+ * ZONE_DEVICE pages in an otherwise ZONE_{NORMAL,MOVABLE}
+ * section.
+ */
+ if (zone_is_zone_device(zone)) {
+ if (!IS_ALIGNED(start_pfn, PAGES_PER_SECTION))
+ section_taint_zone_device(start_pfn);
+ if (!IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION))
+ section_taint_zone_device(start_pfn + nr_pages);
+ }
+
+ /*
+ * TODO now we have a visible range of pages which are not associated
+ * with their zone properly. Not nice but set_pfnblock_flags_mask
+ * expects the zone spans the pfn range. All the pages in the range
+ * are reserved so nobody should be touching them so we should be safe
+ */
+ memmap_init_range(nr_pages, nid, zone_idx(zone), start_pfn, 0,
+ MEMINIT_HOTPLUG, altmap, migratetype);
+
+ set_zone_contiguous(zone);
+}
+
+struct auto_movable_stats {
+ unsigned long kernel_early_pages;
+ unsigned long movable_pages;
+};
+
+static void auto_movable_stats_account_zone(struct auto_movable_stats *stats,
+ struct zone *zone)
+{
+ if (zone_idx(zone) == ZONE_MOVABLE) {
+ stats->movable_pages += zone->present_pages;
+ } else {
+ stats->kernel_early_pages += zone->present_early_pages;
+#ifdef CONFIG_CMA
+ /*
+ * CMA pages (never on hotplugged memory) behave like
+ * ZONE_MOVABLE.
+ */
+ stats->movable_pages += zone->cma_pages;
+ stats->kernel_early_pages -= zone->cma_pages;
+#endif /* CONFIG_CMA */
+ }
+}
+struct auto_movable_group_stats {
+ unsigned long movable_pages;
+ unsigned long req_kernel_early_pages;
+};
+
+static int auto_movable_stats_account_group(struct memory_group *group,
+ void *arg)
+{
+ const int ratio = READ_ONCE(auto_movable_ratio);
+ struct auto_movable_group_stats *stats = arg;
+ long pages;
+
+ /*
+ * We don't support modifying the config while the auto-movable online
+ * policy is already enabled. Just avoid the division by zero below.
+ */
+ if (!ratio)
+ return 0;
+
+ /*
+ * Calculate how many early kernel pages this group requires to
+ * satisfy the configured zone ratio.
+ */
+ pages = group->present_movable_pages * 100 / ratio;
+ pages -= group->present_kernel_pages;
+
+ if (pages > 0)
+ stats->req_kernel_early_pages += pages;
+ stats->movable_pages += group->present_movable_pages;
+ return 0;
+}
+
+static bool auto_movable_can_online_movable(int nid, struct memory_group *group,
+ unsigned long nr_pages)
+{
+ unsigned long kernel_early_pages, movable_pages;
+ struct auto_movable_group_stats group_stats = {};
+ struct auto_movable_stats stats = {};
+ pg_data_t *pgdat = NODE_DATA(nid);
+ struct zone *zone;
+ int i;
+
+ /* Walk all relevant zones and collect MOVABLE vs. KERNEL stats. */
+ if (nid == NUMA_NO_NODE) {
+ /* TODO: cache values */
+ for_each_populated_zone(zone)
+ auto_movable_stats_account_zone(&stats, zone);
+ } else {
+ for (i = 0; i < MAX_NR_ZONES; i++) {
+ zone = pgdat->node_zones + i;
+ if (populated_zone(zone))
+ auto_movable_stats_account_zone(&stats, zone);
+ }
+ }
+
+ kernel_early_pages = stats.kernel_early_pages;
+ movable_pages = stats.movable_pages;
+
+ /*
+ * Kernel memory inside dynamic memory group allows for more MOVABLE
+ * memory within the same group. Remove the effect of all but the
+ * current group from the stats.
+ */
+ walk_dynamic_memory_groups(nid, auto_movable_stats_account_group,
+ group, &group_stats);
+ if (kernel_early_pages <= group_stats.req_kernel_early_pages)
+ return false;
+ kernel_early_pages -= group_stats.req_kernel_early_pages;
+ movable_pages -= group_stats.movable_pages;
+
+ if (group && group->is_dynamic)
+ kernel_early_pages += group->present_kernel_pages;
+
+ /*
+ * Test if we could online the given number of pages to ZONE_MOVABLE
+ * and still stay in the configured ratio.
+ */
+ movable_pages += nr_pages;
+ return movable_pages <= (auto_movable_ratio * kernel_early_pages) / 100;
+}
+
+/*
+ * Returns a default kernel memory zone for the given pfn range.
+ * If no kernel zone covers this pfn range it will automatically go
+ * to the ZONE_NORMAL.
+ */
+static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ struct pglist_data *pgdat = NODE_DATA(nid);
+ int zid;
+
+ for (zid = 0; zid < ZONE_NORMAL; zid++) {
+ struct zone *zone = &pgdat->node_zones[zid];
+
+ if (zone_intersects(zone, start_pfn, nr_pages))
+ return zone;
+ }
+
+ return &pgdat->node_zones[ZONE_NORMAL];
+}
+
+/*
+ * Determine to which zone to online memory dynamically based on user
+ * configuration and system stats. We care about the following ratio:
+ *
+ * MOVABLE : KERNEL
+ *
+ * Whereby MOVABLE is memory in ZONE_MOVABLE and KERNEL is memory in
+ * one of the kernel zones. CMA pages inside one of the kernel zones really
+ * behaves like ZONE_MOVABLE, so we treat them accordingly.
+ *
+ * We don't allow for hotplugged memory in a KERNEL zone to increase the
+ * amount of MOVABLE memory we can have, so we end up with:
+ *
+ * MOVABLE : KERNEL_EARLY
+ *
+ * Whereby KERNEL_EARLY is memory in one of the kernel zones, available sinze
+ * boot. We base our calculation on KERNEL_EARLY internally, because:
+ *
+ * a) Hotplugged memory in one of the kernel zones can sometimes still get
+ * hotunplugged, especially when hot(un)plugging individual memory blocks.
+ * There is no coordination across memory devices, therefore "automatic"
+ * hotunplugging, as implemented in hypervisors, could result in zone
+ * imbalances.
+ * b) Early/boot memory in one of the kernel zones can usually not get
+ * hotunplugged again (e.g., no firmware interface to unplug, fragmented
+ * with unmovable allocations). While there are corner cases where it might
+ * still work, it is barely relevant in practice.
+ *
+ * Exceptions are dynamic memory groups, which allow for more MOVABLE
+ * memory within the same memory group -- because in that case, there is
+ * coordination within the single memory device managed by a single driver.
+ *
+ * We rely on "present pages" instead of "managed pages", as the latter is
+ * highly unreliable and dynamic in virtualized environments, and does not
+ * consider boot time allocations. For example, memory ballooning adjusts the
+ * managed pages when inflating/deflating the balloon, and balloon compaction
+ * can even migrate inflated pages between zones.
+ *
+ * Using "present pages" is better but some things to keep in mind are:
+ *
+ * a) Some memblock allocations, such as for the crashkernel area, are
+ * effectively unused by the kernel, yet they account to "present pages".
+ * Fortunately, these allocations are comparatively small in relevant setups
+ * (e.g., fraction of system memory).
+ * b) Some hotplugged memory blocks in virtualized environments, esecially
+ * hotplugged by virtio-mem, look like they are completely present, however,
+ * only parts of the memory block are actually currently usable.
+ * "present pages" is an upper limit that can get reached at runtime. As
+ * we base our calculations on KERNEL_EARLY, this is not an issue.
+ */
+static struct zone *auto_movable_zone_for_pfn(int nid,
+ struct memory_group *group,
+ unsigned long pfn,
+ unsigned long nr_pages)
+{
+ unsigned long online_pages = 0, max_pages, end_pfn;
+ struct page *page;
+
+ if (!auto_movable_ratio)
+ goto kernel_zone;
+
+ if (group && !group->is_dynamic) {
+ max_pages = group->s.max_pages;
+ online_pages = group->present_movable_pages;
+
+ /* If anything is !MOVABLE online the rest !MOVABLE. */
+ if (group->present_kernel_pages)
+ goto kernel_zone;
+ } else if (!group || group->d.unit_pages == nr_pages) {
+ max_pages = nr_pages;
+ } else {
+ max_pages = group->d.unit_pages;
+ /*
+ * Take a look at all online sections in the current unit.
+ * We can safely assume that all pages within a section belong
+ * to the same zone, because dynamic memory groups only deal
+ * with hotplugged memory.
+ */
+ pfn = ALIGN_DOWN(pfn, group->d.unit_pages);
+ end_pfn = pfn + group->d.unit_pages;
+ for (; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
+ page = pfn_to_online_page(pfn);
+ if (!page)
+ continue;
+ /* If anything is !MOVABLE online the rest !MOVABLE. */
+ if (!is_zone_movable_page(page))
+ goto kernel_zone;
+ online_pages += PAGES_PER_SECTION;
+ }
+ }
+
+ /*
+ * Online MOVABLE if we could *currently* online all remaining parts
+ * MOVABLE. We expect to (add+) online them immediately next, so if
+ * nobody interferes, all will be MOVABLE if possible.
+ */
+ nr_pages = max_pages - online_pages;
+ if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages))
+ goto kernel_zone;
+
+#ifdef CONFIG_NUMA
+ if (auto_movable_numa_aware &&
+ !auto_movable_can_online_movable(nid, group, nr_pages))
+ goto kernel_zone;
+#endif /* CONFIG_NUMA */
+
+ return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
+kernel_zone:
+ return default_kernel_zone_for_pfn(nid, pfn, nr_pages);
+}
+
+static inline struct zone *default_zone_for_pfn(int nid, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ struct zone *kernel_zone = default_kernel_zone_for_pfn(nid, start_pfn,
+ nr_pages);
+ struct zone *movable_zone = &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
+ bool in_kernel = zone_intersects(kernel_zone, start_pfn, nr_pages);
+ bool in_movable = zone_intersects(movable_zone, start_pfn, nr_pages);
+
+ /*
+ * We inherit the existing zone in a simple case where zones do not
+ * overlap in the given range
+ */
+ if (in_kernel ^ in_movable)
+ return (in_kernel) ? kernel_zone : movable_zone;
+
+ /*
+ * If the range doesn't belong to any zone or two zones overlap in the
+ * given range then we use movable zone only if movable_node is
+ * enabled because we always online to a kernel zone by default.
+ */
+ return movable_node_enabled ? movable_zone : kernel_zone;
+}
+
+struct zone *zone_for_pfn_range(int online_type, int nid,
+ struct memory_group *group, unsigned long start_pfn,
+ unsigned long nr_pages)
+{
+ if (online_type == MMOP_ONLINE_KERNEL)
+ return default_kernel_zone_for_pfn(nid, start_pfn, nr_pages);
+
+ if (online_type == MMOP_ONLINE_MOVABLE)
+ return &NODE_DATA(nid)->node_zones[ZONE_MOVABLE];
+
+ if (online_policy == ONLINE_POLICY_AUTO_MOVABLE)
+ return auto_movable_zone_for_pfn(nid, group, start_pfn, nr_pages);
+
+ return default_zone_for_pfn(nid, start_pfn, nr_pages);
+}
+
+/*
+ * This function should only be called by memory_block_{online,offline},
+ * and {online,offline}_pages.
+ */
+void adjust_present_page_count(struct page *page, struct memory_group *group,
+ long nr_pages)
+{
+ struct zone *zone = page_zone(page);
+ const bool movable = zone_idx(zone) == ZONE_MOVABLE;
+
+ /*
+ * We only support onlining/offlining/adding/removing of complete
+ * memory blocks; therefore, either all is either early or hotplugged.
+ */
+ if (early_section(__pfn_to_section(page_to_pfn(page))))
+ zone->present_early_pages += nr_pages;
+ zone->present_pages += nr_pages;
+ zone->zone_pgdat->node_present_pages += nr_pages;
+
+ if (group && movable)
+ group->present_movable_pages += nr_pages;
+ else if (group && !movable)
+ group->present_kernel_pages += nr_pages;
+}
+
+int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages,
+ struct zone *zone)
+{
+ unsigned long end_pfn = pfn + nr_pages;
+ int ret, i;
+
+ ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
+ if (ret)
+ return ret;
+
+ move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE);
+
+ for (i = 0; i < nr_pages; i++)
+ SetPageVmemmapSelfHosted(pfn_to_page(pfn + i));
+
+ /*
+ * It might be that the vmemmap_pages fully span sections. If that is
+ * the case, mark those sections online here as otherwise they will be
+ * left offline.
+ */
+ if (nr_pages >= PAGES_PER_SECTION)
+ online_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
+
+ return ret;
+}
+
+void mhp_deinit_memmap_on_memory(unsigned long pfn, unsigned long nr_pages)
+{
+ unsigned long end_pfn = pfn + nr_pages;
+
+ /*
+ * It might be that the vmemmap_pages fully span sections. If that is
+ * the case, mark those sections offline here as otherwise they will be
+ * left online.
+ */
+ if (nr_pages >= PAGES_PER_SECTION)
+ offline_mem_sections(pfn, ALIGN_DOWN(end_pfn, PAGES_PER_SECTION));
+
+ /*
+ * The pages associated with this vmemmap have been offlined, so
+ * we can reset its state here.
+ */
+ remove_pfn_range_from_zone(page_zone(pfn_to_page(pfn)), pfn, nr_pages);
+ kasan_remove_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages));
+}
+
+/*
+ * Must be called with mem_hotplug_lock in write mode.
+ */
+int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
+ struct zone *zone, struct memory_group *group)
+{
+ unsigned long flags;
+ int need_zonelists_rebuild = 0;
+ const int nid = zone_to_nid(zone);
+ int ret;
+ struct memory_notify arg;
+
+ /*
+ * {on,off}lining is constrained to full memory sections (or more
+ * precisely to memory blocks from the user space POV).
+ * memmap_on_memory is an exception because it reserves initial part
+ * of the physical memory space for vmemmaps. That space is pageblock
+ * aligned.
+ */
+ if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(pfn) ||
+ !IS_ALIGNED(pfn + nr_pages, PAGES_PER_SECTION)))
+ return -EINVAL;
+
+
+ /* associate pfn range with the zone */
+ move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_ISOLATE);
+
+ arg.start_pfn = pfn;
+ arg.nr_pages = nr_pages;
+ node_states_check_changes_online(nr_pages, zone, &arg);
+
+ ret = memory_notify(MEM_GOING_ONLINE, &arg);
+ ret = notifier_to_errno(ret);
+ if (ret)
+ goto failed_addition;
+
+ /*
+ * Fixup the number of isolated pageblocks before marking the sections
+ * onlining, such that undo_isolate_page_range() works correctly.
+ */
+ spin_lock_irqsave(&zone->lock, flags);
+ zone->nr_isolate_pageblock += nr_pages / pageblock_nr_pages;
+ spin_unlock_irqrestore(&zone->lock, flags);
+
+ /*
+ * If this zone is not populated, then it is not in zonelist.
+ * This means the page allocator ignores this zone.
+ * So, zonelist must be updated after online.
+ */
+ if (!populated_zone(zone)) {
+ need_zonelists_rebuild = 1;
+ setup_zone_pageset(zone);
+ }
+
+ online_pages_range(pfn, nr_pages);
+ adjust_present_page_count(pfn_to_page(pfn), group, nr_pages);
+
+ node_states_set_node(nid, &arg);
+ if (need_zonelists_rebuild)
+ build_all_zonelists(NULL);
+
+ /* Basic onlining is complete, allow allocation of onlined pages. */
+ undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
+
+ /*
+ * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
+ * the tail of the freelist when undoing isolation). Shuffle the whole
+ * zone to make sure the just onlined pages are properly distributed
+ * across the whole freelist - to create an initial shuffle.
+ */
+ shuffle_zone(zone);
+
+ /* reinitialise watermarks and update pcp limits */
+ init_per_zone_wmark_min();
+
+ kswapd_run(nid);
+ kcompactd_run(nid);
+
+ writeback_set_ratelimit();
+
+ memory_notify(MEM_ONLINE, &arg);
+ return 0;
+
+failed_addition:
+ pr_debug("online_pages [mem %#010llx-%#010llx] failed\n",
+ (unsigned long long) pfn << PAGE_SHIFT,
+ (((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
+ memory_notify(MEM_CANCEL_ONLINE, &arg);
+ remove_pfn_range_from_zone(zone, pfn, nr_pages);
+ return ret;
+}
+
+/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+static pg_data_t __ref *hotadd_init_pgdat(int nid)
+{
+ struct pglist_data *pgdat;
+
+ /*
+ * NODE_DATA is preallocated (free_area_init) but its internal
+ * state is not allocated completely. Add missing pieces.
+ * Completely offline nodes stay around and they just need
+ * reintialization.
+ */
+ pgdat = NODE_DATA(nid);
+
+ /* init node's zones as empty zones, we don't have any present pages.*/
+ free_area_init_core_hotplug(pgdat);
+
+ /*
+ * The node we allocated has no zone fallback lists. For avoiding
+ * to access not-initialized zonelist, build here.
+ */
+ build_all_zonelists(pgdat);
+
+ return pgdat;
+}
+
+/*
+ * __try_online_node - online a node if offlined
+ * @nid: the node ID
+ * @set_node_online: Whether we want to online the node
+ * called by cpu_up() to online a node without onlined memory.
+ *
+ * Returns:
+ * 1 -> a new node has been allocated
+ * 0 -> the node is already online
+ * -ENOMEM -> the node could not be allocated
+ */
+static int __try_online_node(int nid, bool set_node_online)
+{
+ pg_data_t *pgdat;
+ int ret = 1;
+
+ if (node_online(nid))
+ return 0;
+
+ pgdat = hotadd_init_pgdat(nid);
+ if (!pgdat) {
+ pr_err("Cannot online node %d due to NULL pgdat\n", nid);
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ if (set_node_online) {
+ node_set_online(nid);
+ ret = register_one_node(nid);
+ BUG_ON(ret);
+ }
+out:
+ return ret;
+}
+
+/*
+ * Users of this function always want to online/register the node
+ */
+int try_online_node(int nid)
+{
+ int ret;
+
+ mem_hotplug_begin();
+ ret = __try_online_node(nid, true);
+ mem_hotplug_done();
+ return ret;
+}
+
+static int check_hotplug_memory_range(u64 start, u64 size)
+{
+ /* memory range must be block size aligned */
+ if (!size || !IS_ALIGNED(start, memory_block_size_bytes()) ||
+ !IS_ALIGNED(size, memory_block_size_bytes())) {
+ pr_err("Block size [%#lx] unaligned hotplug range: start %#llx, size %#llx",
+ memory_block_size_bytes(), start, size);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int online_memory_block(struct memory_block *mem, void *arg)
+{
+ mem->online_type = mhp_default_online_type;
+ return device_online(&mem->dev);
+}
+
+#ifndef arch_supports_memmap_on_memory
+static inline bool arch_supports_memmap_on_memory(unsigned long vmemmap_size)
+{
+ /*
+ * As default, we want the vmemmap to span a complete PMD such that we
+ * can map the vmemmap using a single PMD if supported by the
+ * architecture.
+ */
+ return IS_ALIGNED(vmemmap_size, PMD_SIZE);
+}
+#endif
+
+static bool mhp_supports_memmap_on_memory(unsigned long size)
+{
+ unsigned long vmemmap_size = memory_block_memmap_size();
+ unsigned long memmap_pages = memory_block_memmap_on_memory_pages();
+
+ /*
+ * Besides having arch support and the feature enabled at runtime, we
+ * need a few more assumptions to hold true:
+ *
+ * a) We span a single memory block: memory onlining/offlinin;g happens
+ * in memory block granularity. We don't want the vmemmap of online
+ * memory blocks to reside on offline memory blocks. In the future,
+ * we might want to support variable-sized memory blocks to make the
+ * feature more versatile.
+ *
+ * b) The vmemmap pages span complete PMDs: We don't want vmemmap code
+ * to populate memory from the altmap for unrelated parts (i.e.,
+ * other memory blocks)
+ *
+ * c) The vmemmap pages (and thereby the pages that will be exposed to
+ * the buddy) have to cover full pageblocks: memory onlining/offlining
+ * code requires applicable ranges to be page-aligned, for example, to
+ * set the migratetypes properly.
+ *
+ * TODO: Although we have a check here to make sure that vmemmap pages
+ * fully populate a PMD, it is not the right place to check for
+ * this. A much better solution involves improving vmemmap code
+ * to fallback to base pages when trying to populate vmemmap using
+ * altmap as an alternative source of memory, and we do not exactly
+ * populate a single PMD.
+ */
+ if (!mhp_memmap_on_memory() || size != memory_block_size_bytes())
+ return false;
+
+ /*
+ * Make sure the vmemmap allocation is fully contained
+ * so that we always allocate vmemmap memory from altmap area.
+ */
+ if (!IS_ALIGNED(vmemmap_size, PAGE_SIZE))
+ return false;
+
+ /*
+ * start pfn should be pageblock_nr_pages aligned for correctly
+ * setting migrate types
+ */
+ if (!pageblock_aligned(memmap_pages))
+ return false;
+
+ if (memmap_pages == PHYS_PFN(memory_block_size_bytes()))
+ /* No effective hotplugged memory doesn't make sense. */
+ return false;
+
+ return arch_supports_memmap_on_memory(vmemmap_size);
+}
+
+/*
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations (triggered e.g. by sysfs).
+ *
+ * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
+ */
+int __ref add_memory_resource(int nid, struct resource *res, mhp_t mhp_flags)
+{
+ struct mhp_params params = { .pgprot = pgprot_mhp(PAGE_KERNEL) };
+ enum memblock_flags memblock_flags = MEMBLOCK_NONE;
+ struct vmem_altmap mhp_altmap = {
+ .base_pfn = PHYS_PFN(res->start),
+ .end_pfn = PHYS_PFN(res->end),
+ };
+ struct memory_group *group = NULL;
+ u64 start, size;
+ bool new_node = false;
+ int ret;
+
+ start = res->start;
+ size = resource_size(res);
+
+ ret = check_hotplug_memory_range(start, size);
+ if (ret)
+ return ret;
+
+ if (mhp_flags & MHP_NID_IS_MGID) {
+ group = memory_group_find_by_id(nid);
+ if (!group)
+ return -EINVAL;
+ nid = group->nid;
+ }
+
+ if (!node_possible(nid)) {
+ WARN(1, "node %d was absent from the node_possible_map\n", nid);
+ return -EINVAL;
+ }
+
+ mem_hotplug_begin();
+
+ if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+ if (res->flags & IORESOURCE_SYSRAM_DRIVER_MANAGED)
+ memblock_flags = MEMBLOCK_DRIVER_MANAGED;
+ ret = memblock_add_node(start, size, nid, memblock_flags);
+ if (ret)
+ goto error_mem_hotplug_end;
+ }
+
+ ret = __try_online_node(nid, false);
+ if (ret < 0)
+ goto error;
+ new_node = ret;
+
+ /*
+ * Self hosted memmap array
+ */
+ if (mhp_flags & MHP_MEMMAP_ON_MEMORY) {
+ if (mhp_supports_memmap_on_memory(size)) {
+ mhp_altmap.free = memory_block_memmap_on_memory_pages();
+ params.altmap = kmalloc(sizeof(struct vmem_altmap), GFP_KERNEL);
+ if (!params.altmap) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ memcpy(params.altmap, &mhp_altmap, sizeof(mhp_altmap));
+ }
+ /* fallback to not using altmap */
+ }
+
+ /* call arch's memory hotadd */
+ ret = arch_add_memory(nid, start, size, &params);
+ if (ret < 0)
+ goto error_free;
+
+ /* create memory block devices after memory was added */
+ ret = create_memory_block_devices(start, size, params.altmap, group);
+ if (ret) {
+ arch_remove_memory(start, size, params.altmap);
+ goto error_free;
+ }
+
+ if (new_node) {
+ /* If sysfs file of new node can't be created, cpu on the node
+ * can't be hot-added. There is no rollback way now.
+ * So, check by BUG_ON() to catch it reluctantly..
+ * We online node here. We can't roll back from here.
+ */
+ node_set_online(nid);
+ ret = __register_one_node(nid);
+ BUG_ON(ret);
+ }
+
+ register_memory_blocks_under_node(nid, PFN_DOWN(start),
+ PFN_UP(start + size - 1),
+ MEMINIT_HOTPLUG);
+
+ /* create new memmap entry */
+ if (!strcmp(res->name, "System RAM"))
+ firmware_map_add_hotplug(start, start + size, "System RAM");
+
+ /* device_online() will take the lock when calling online_pages() */
+ mem_hotplug_done();
+
+ /*
+ * In case we're allowed to merge the resource, flag it and trigger
+ * merging now that adding succeeded.
+ */
+ if (mhp_flags & MHP_MERGE_RESOURCE)
+ merge_system_ram_resource(res);
+
+ /* online pages if requested */
+ if (mhp_default_online_type != MMOP_OFFLINE)
+ walk_memory_blocks(start, size, NULL, online_memory_block);
+
+ return ret;
+error_free:
+ kfree(params.altmap);
+error:
+ if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK))
+ memblock_remove(start, size);
+error_mem_hotplug_end:
+ mem_hotplug_done();
+ return ret;
+}
+
+/* requires device_hotplug_lock, see add_memory_resource() */
+int __ref __add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
+{
+ struct resource *res;
+ int ret;
+
+ res = register_memory_resource(start, size, "System RAM");
+ if (IS_ERR(res))
+ return PTR_ERR(res);
+
+ ret = add_memory_resource(nid, res, mhp_flags);
+ if (ret < 0)
+ release_memory_resource(res);
+ return ret;
+}
+
+int add_memory(int nid, u64 start, u64 size, mhp_t mhp_flags)
+{
+ int rc;
+
+ lock_device_hotplug();
+ rc = __add_memory(nid, start, size, mhp_flags);
+ unlock_device_hotplug();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(add_memory);
+
+/*
+ * Add special, driver-managed memory to the system as system RAM. Such
+ * memory is not exposed via the raw firmware-provided memmap as system
+ * RAM, instead, it is detected and added by a driver - during cold boot,
+ * after a reboot, and after kexec.
+ *
+ * Reasons why this memory should not be used for the initial memmap of a
+ * kexec kernel or for placing kexec images:
+ * - The booting kernel is in charge of determining how this memory will be
+ * used (e.g., use persistent memory as system RAM)
+ * - Coordination with a hypervisor is required before this memory
+ * can be used (e.g., inaccessible parts).
+ *
+ * For this memory, no entries in /sys/firmware/memmap ("raw firmware-provided
+ * memory map") are created. Also, the created memory resource is flagged
+ * with IORESOURCE_SYSRAM_DRIVER_MANAGED, so in-kernel users can special-case
+ * this memory as well (esp., not place kexec images onto it).
+ *
+ * The resource_name (visible via /proc/iomem) has to have the format
+ * "System RAM ($DRIVER)".
+ */
+int add_memory_driver_managed(int nid, u64 start, u64 size,
+ const char *resource_name, mhp_t mhp_flags)
+{
+ struct resource *res;
+ int rc;
+
+ if (!resource_name ||
+ strstr(resource_name, "System RAM (") != resource_name ||
+ resource_name[strlen(resource_name) - 1] != ')')
+ return -EINVAL;
+
+ lock_device_hotplug();
+
+ res = register_memory_resource(start, size, resource_name);
+ if (IS_ERR(res)) {
+ rc = PTR_ERR(res);
+ goto out_unlock;
+ }
+
+ rc = add_memory_resource(nid, res, mhp_flags);
+ if (rc < 0)
+ release_memory_resource(res);
+
+out_unlock:
+ unlock_device_hotplug();
+ return rc;
+}
+EXPORT_SYMBOL_GPL(add_memory_driver_managed);
+
+/*
+ * Platforms should define arch_get_mappable_range() that provides
+ * maximum possible addressable physical memory range for which the
+ * linear mapping could be created. The platform returned address
+ * range must adhere to these following semantics.
+ *
+ * - range.start <= range.end
+ * - Range includes both end points [range.start..range.end]
+ *
+ * There is also a fallback definition provided here, allowing the
+ * entire possible physical address range in case any platform does
+ * not define arch_get_mappable_range().
+ */
+struct range __weak arch_get_mappable_range(void)
+{
+ struct range mhp_range = {
+ .start = 0UL,
+ .end = -1ULL,
+ };
+ return mhp_range;
+}
+
+struct range mhp_get_pluggable_range(bool need_mapping)
+{
+ const u64 max_phys = (1ULL << MAX_PHYSMEM_BITS) - 1;
+ struct range mhp_range;
+
+ if (need_mapping) {
+ mhp_range = arch_get_mappable_range();
+ if (mhp_range.start > max_phys) {
+ mhp_range.start = 0;
+ mhp_range.end = 0;
+ }
+ mhp_range.end = min_t(u64, mhp_range.end, max_phys);
+ } else {
+ mhp_range.start = 0;
+ mhp_range.end = max_phys;
+ }
+ return mhp_range;
+}
+EXPORT_SYMBOL_GPL(mhp_get_pluggable_range);
+
+bool mhp_range_allowed(u64 start, u64 size, bool need_mapping)
+{
+ struct range mhp_range = mhp_get_pluggable_range(need_mapping);
+ u64 end = start + size;
+
+ if (start < end && start >= mhp_range.start && (end - 1) <= mhp_range.end)
+ return true;
+
+ pr_warn("Hotplug memory [%#llx-%#llx] exceeds maximum addressable range [%#llx-%#llx]\n",
+ start, end, mhp_range.start, mhp_range.end);
+ return false;
+}
+
+#ifdef CONFIG_MEMORY_HOTREMOVE
+/*
+ * Scan pfn range [start,end) to find movable/migratable pages (LRU pages,
+ * non-lru movable pages and hugepages). Will skip over most unmovable
+ * pages (esp., pages that can be skipped when offlining), but bail out on
+ * definitely unmovable pages.
+ *
+ * Returns:
+ * 0 in case a movable page is found and movable_pfn was updated.
+ * -ENOENT in case no movable page was found.
+ * -EBUSY in case a definitely unmovable page was found.
+ */
+static int scan_movable_pages(unsigned long start, unsigned long end,
+ unsigned long *movable_pfn)
+{
+ unsigned long pfn;
+
+ for (pfn = start; pfn < end; pfn++) {
+ struct page *page, *head;
+ unsigned long skip;
+
+ if (!pfn_valid(pfn))
+ continue;
+ page = pfn_to_page(pfn);
+ if (PageLRU(page))
+ goto found;
+ if (__PageMovable(page))
+ goto found;
+
+ /*
+ * PageOffline() pages that are not marked __PageMovable() and
+ * have a reference count > 0 (after MEM_GOING_OFFLINE) are
+ * definitely unmovable. If their reference count would be 0,
+ * they could at least be skipped when offlining memory.
+ */
+ if (PageOffline(page) && page_count(page))
+ return -EBUSY;
+
+ if (!PageHuge(page))
+ continue;
+ head = compound_head(page);
+ /*
+ * This test is racy as we hold no reference or lock. The
+ * hugetlb page could have been free'ed and head is no longer
+ * a hugetlb page before the following check. In such unlikely
+ * cases false positives and negatives are possible. Calling
+ * code must deal with these scenarios.
+ */
+ if (HPageMigratable(head))
+ goto found;
+ skip = compound_nr(head) - (pfn - page_to_pfn(head));
+ pfn += skip - 1;
+ }
+ return -ENOENT;
+found:
+ *movable_pfn = pfn;
+ return 0;
+}
+
+static void do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
+{
+ unsigned long pfn;
+ struct page *page, *head;
+ LIST_HEAD(source);
+ static DEFINE_RATELIMIT_STATE(migrate_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+
+ for (pfn = start_pfn; pfn < end_pfn; pfn++) {
+ struct folio *folio;
+ bool isolated;
+
+ if (!pfn_valid(pfn))
+ continue;
+ page = pfn_to_page(pfn);
+ folio = page_folio(page);
+ head = &folio->page;
+
+ if (PageHuge(page)) {
+ pfn = page_to_pfn(head) + compound_nr(head) - 1;
+ isolate_hugetlb(folio, &source);
+ continue;
+ } else if (PageTransHuge(page))
+ pfn = page_to_pfn(head) + thp_nr_pages(page) - 1;
+
+ /*
+ * HWPoison pages have elevated reference counts so the migration would
+ * fail on them. It also doesn't make any sense to migrate them in the
+ * first place. Still try to unmap such a page in case it is still mapped
+ * (e.g. current hwpoison implementation doesn't unmap KSM pages but keep
+ * the unmap as the catch all safety net).
+ */
+ if (PageHWPoison(page)) {
+ if (WARN_ON(folio_test_lru(folio)))
+ folio_isolate_lru(folio);
+ if (folio_mapped(folio))
+ try_to_unmap(folio, TTU_IGNORE_MLOCK);
+ continue;
+ }
+
+ if (!get_page_unless_zero(page))
+ continue;
+ /*
+ * We can skip free pages. And we can deal with pages on
+ * LRU and non-lru movable pages.
+ */
+ if (PageLRU(page))
+ isolated = isolate_lru_page(page);
+ else
+ isolated = isolate_movable_page(page, ISOLATE_UNEVICTABLE);
+ if (isolated) {
+ list_add_tail(&page->lru, &source);
+ if (!__PageMovable(page))
+ inc_node_page_state(page, NR_ISOLATED_ANON +
+ page_is_file_lru(page));
+
+ } else {
+ if (__ratelimit(&migrate_rs)) {
+ pr_warn("failed to isolate pfn %lx\n", pfn);
+ dump_page(page, "isolation failed");
+ }
+ }
+ put_page(page);
+ }
+ if (!list_empty(&source)) {
+ nodemask_t nmask = node_states[N_MEMORY];
+ struct migration_target_control mtc = {
+ .nmask = &nmask,
+ .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL,
+ };
+ int ret;
+
+ /*
+ * We have checked that migration range is on a single zone so
+ * we can use the nid of the first page to all the others.
+ */
+ mtc.nid = page_to_nid(list_first_entry(&source, struct page, lru));
+
+ /*
+ * try to allocate from a different node but reuse this node
+ * if there are no other online nodes to be used (e.g. we are
+ * offlining a part of the only existing node)
+ */
+ node_clear(mtc.nid, nmask);
+ if (nodes_empty(nmask))
+ node_set(mtc.nid, nmask);
+ ret = migrate_pages(&source, alloc_migration_target, NULL,
+ (unsigned long)&mtc, MIGRATE_SYNC, MR_MEMORY_HOTPLUG, NULL);
+ if (ret) {
+ list_for_each_entry(page, &source, lru) {
+ if (__ratelimit(&migrate_rs)) {
+ pr_warn("migrating pfn %lx failed ret:%d\n",
+ page_to_pfn(page), ret);
+ dump_page(page, "migration failure");
+ }
+ }
+ putback_movable_pages(&source);
+ }
+ }
+}
+
+static int __init cmdline_parse_movable_node(char *p)
+{
+ movable_node_enabled = true;
+ return 0;
+}
+early_param("movable_node", cmdline_parse_movable_node);
+
+/* check which state of node_states will be changed when offline memory */
+static void node_states_check_changes_offline(unsigned long nr_pages,
+ struct zone *zone, struct memory_notify *arg)
+{
+ struct pglist_data *pgdat = zone->zone_pgdat;
+ unsigned long present_pages = 0;
+ enum zone_type zt;
+
+ arg->status_change_nid = NUMA_NO_NODE;
+ arg->status_change_nid_normal = NUMA_NO_NODE;
+
+ /*
+ * Check whether node_states[N_NORMAL_MEMORY] will be changed.
+ * If the memory to be offline is within the range
+ * [0..ZONE_NORMAL], and it is the last present memory there,
+ * the zones in that range will become empty after the offlining,
+ * thus we can determine that we need to clear the node from
+ * node_states[N_NORMAL_MEMORY].
+ */
+ for (zt = 0; zt <= ZONE_NORMAL; zt++)
+ present_pages += pgdat->node_zones[zt].present_pages;
+ if (zone_idx(zone) <= ZONE_NORMAL && nr_pages >= present_pages)
+ arg->status_change_nid_normal = zone_to_nid(zone);
+
+ /*
+ * We have accounted the pages from [0..ZONE_NORMAL); ZONE_HIGHMEM
+ * does not apply as we don't support 32bit.
+ * Here we count the possible pages from ZONE_MOVABLE.
+ * If after having accounted all the pages, we see that the nr_pages
+ * to be offlined is over or equal to the accounted pages,
+ * we know that the node will become empty, and so, we can clear
+ * it for N_MEMORY as well.
+ */
+ present_pages += pgdat->node_zones[ZONE_MOVABLE].present_pages;
+
+ if (nr_pages >= present_pages)
+ arg->status_change_nid = zone_to_nid(zone);
+}
+
+static void node_states_clear_node(int node, struct memory_notify *arg)
+{
+ if (arg->status_change_nid_normal >= 0)
+ node_clear_state(node, N_NORMAL_MEMORY);
+
+ if (arg->status_change_nid >= 0)
+ node_clear_state(node, N_MEMORY);
+}
+
+static int count_system_ram_pages_cb(unsigned long start_pfn,
+ unsigned long nr_pages, void *data)
+{
+ unsigned long *nr_system_ram_pages = data;
+
+ *nr_system_ram_pages += nr_pages;
+ return 0;
+}
+
+/*
+ * Must be called with mem_hotplug_lock in write mode.
+ */
+int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
+ struct zone *zone, struct memory_group *group)
+{
+ const unsigned long end_pfn = start_pfn + nr_pages;
+ unsigned long pfn, system_ram_pages = 0;
+ const int node = zone_to_nid(zone);
+ unsigned long flags;
+ struct memory_notify arg;
+ char *reason;
+ int ret;
+
+ /*
+ * {on,off}lining is constrained to full memory sections (or more
+ * precisely to memory blocks from the user space POV).
+ * memmap_on_memory is an exception because it reserves initial part
+ * of the physical memory space for vmemmaps. That space is pageblock
+ * aligned.
+ */
+ if (WARN_ON_ONCE(!nr_pages || !pageblock_aligned(start_pfn) ||
+ !IS_ALIGNED(start_pfn + nr_pages, PAGES_PER_SECTION)))
+ return -EINVAL;
+
+ /*
+ * Don't allow to offline memory blocks that contain holes.
+ * Consequently, memory blocks with holes can never get onlined
+ * via the hotplug path - online_pages() - as hotplugged memory has
+ * no holes. This way, we e.g., don't have to worry about marking
+ * memory holes PG_reserved, don't need pfn_valid() checks, and can
+ * avoid using walk_system_ram_range() later.
+ */
+ walk_system_ram_range(start_pfn, nr_pages, &system_ram_pages,
+ count_system_ram_pages_cb);
+ if (system_ram_pages != nr_pages) {
+ ret = -EINVAL;
+ reason = "memory holes";
+ goto failed_removal;
+ }
+
+ /*
+ * We only support offlining of memory blocks managed by a single zone,
+ * checked by calling code. This is just a sanity check that we might
+ * want to remove in the future.
+ */
+ if (WARN_ON_ONCE(page_zone(pfn_to_page(start_pfn)) != zone ||
+ page_zone(pfn_to_page(end_pfn - 1)) != zone)) {
+ ret = -EINVAL;
+ reason = "multizone range";
+ goto failed_removal;
+ }
+
+ /*
+ * Disable pcplists so that page isolation cannot race with freeing
+ * in a way that pages from isolated pageblock are left on pcplists.
+ */
+ zone_pcp_disable(zone);
+ lru_cache_disable();
+
+ /* set above range as isolated */
+ ret = start_isolate_page_range(start_pfn, end_pfn,
+ MIGRATE_MOVABLE,
+ MEMORY_OFFLINE | REPORT_FAILURE,
+ GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
+ if (ret) {
+ reason = "failure to isolate range";
+ goto failed_removal_pcplists_disabled;
+ }
+
+ arg.start_pfn = start_pfn;
+ arg.nr_pages = nr_pages;
+ node_states_check_changes_offline(nr_pages, zone, &arg);
+
+ ret = memory_notify(MEM_GOING_OFFLINE, &arg);
+ ret = notifier_to_errno(ret);
+ if (ret) {
+ reason = "notifier failure";
+ goto failed_removal_isolated;
+ }
+
+ do {
+ pfn = start_pfn;
+ do {
+ /*
+ * Historically we always checked for any signal and
+ * can't limit it to fatal signals without eventually
+ * breaking user space.
+ */
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ reason = "signal backoff";
+ goto failed_removal_isolated;
+ }
+
+ cond_resched();
+
+ ret = scan_movable_pages(pfn, end_pfn, &pfn);
+ if (!ret) {
+ /*
+ * TODO: fatal migration failures should bail
+ * out
+ */
+ do_migrate_range(pfn, end_pfn);
+ }
+ } while (!ret);
+
+ if (ret != -ENOENT) {
+ reason = "unmovable page";
+ goto failed_removal_isolated;
+ }
+
+ /*
+ * Dissolve free hugepages in the memory block before doing
+ * offlining actually in order to make hugetlbfs's object
+ * counting consistent.
+ */
+ ret = dissolve_free_huge_pages(start_pfn, end_pfn);
+ if (ret) {
+ reason = "failure to dissolve huge pages";
+ goto failed_removal_isolated;
+ }
+
+ ret = test_pages_isolated(start_pfn, end_pfn, MEMORY_OFFLINE);
+
+ } while (ret);
+
+ /* Mark all sections offline and remove free pages from the buddy. */
+ __offline_isolated_pages(start_pfn, end_pfn);
+ pr_debug("Offlined Pages %ld\n", nr_pages);
+
+ /*
+ * The memory sections are marked offline, and the pageblock flags
+ * effectively stale; nobody should be touching them. Fixup the number
+ * of isolated pageblocks, memory onlining will properly revert this.
+ */
+ spin_lock_irqsave(&zone->lock, flags);
+ zone->nr_isolate_pageblock -= nr_pages / pageblock_nr_pages;
+ spin_unlock_irqrestore(&zone->lock, flags);
+
+ lru_cache_enable();
+ zone_pcp_enable(zone);
+
+ /* removal success */
+ adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
+ adjust_present_page_count(pfn_to_page(start_pfn), group, -nr_pages);
+
+ /* reinitialise watermarks and update pcp limits */
+ init_per_zone_wmark_min();
+
+ if (!populated_zone(zone)) {
+ zone_pcp_reset(zone);
+ build_all_zonelists(NULL);
+ }
+
+ node_states_clear_node(node, &arg);
+ if (arg.status_change_nid >= 0) {
+ kcompactd_stop(node);
+ kswapd_stop(node);
+ }
+
+ writeback_set_ratelimit();
+
+ memory_notify(MEM_OFFLINE, &arg);
+ remove_pfn_range_from_zone(zone, start_pfn, nr_pages);
+ return 0;
+
+failed_removal_isolated:
+ /* pushback to free area */
+ undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
+ memory_notify(MEM_CANCEL_OFFLINE, &arg);
+failed_removal_pcplists_disabled:
+ lru_cache_enable();
+ zone_pcp_enable(zone);
+failed_removal:
+ pr_debug("memory offlining [mem %#010llx-%#010llx] failed due to %s\n",
+ (unsigned long long) start_pfn << PAGE_SHIFT,
+ ((unsigned long long) end_pfn << PAGE_SHIFT) - 1,
+ reason);
+ return ret;
+}
+
+static int check_memblock_offlined_cb(struct memory_block *mem, void *arg)
+{
+ int *nid = arg;
+
+ *nid = mem->nid;
+ if (unlikely(mem->state != MEM_OFFLINE)) {
+ phys_addr_t beginpa, endpa;
+
+ beginpa = PFN_PHYS(section_nr_to_pfn(mem->start_section_nr));
+ endpa = beginpa + memory_block_size_bytes() - 1;
+ pr_warn("removing memory fails, because memory [%pa-%pa] is onlined\n",
+ &beginpa, &endpa);
+
+ return -EBUSY;
+ }
+ return 0;
+}
+
+static int test_has_altmap_cb(struct memory_block *mem, void *arg)
+{
+ struct memory_block **mem_ptr = (struct memory_block **)arg;
+ /*
+ * return the memblock if we have altmap
+ * and break callback.
+ */
+ if (mem->altmap) {
+ *mem_ptr = mem;
+ return 1;
+ }
+ return 0;
+}
+
+static int check_cpu_on_node(int nid)
+{
+ int cpu;
+
+ for_each_present_cpu(cpu) {
+ if (cpu_to_node(cpu) == nid)
+ /*
+ * the cpu on this node isn't removed, and we can't
+ * offline this node.
+ */
+ return -EBUSY;
+ }
+
+ return 0;
+}
+
+static int check_no_memblock_for_node_cb(struct memory_block *mem, void *arg)
+{
+ int nid = *(int *)arg;
+
+ /*
+ * If a memory block belongs to multiple nodes, the stored nid is not
+ * reliable. However, such blocks are always online (e.g., cannot get
+ * offlined) and, therefore, are still spanned by the node.
+ */
+ return mem->nid == nid ? -EEXIST : 0;
+}
+
+/**
+ * try_offline_node
+ * @nid: the node ID
+ *
+ * Offline a node if all memory sections and cpus of the node are removed.
+ *
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations before this call.
+ */
+void try_offline_node(int nid)
+{
+ int rc;
+
+ /*
+ * If the node still spans pages (especially ZONE_DEVICE), don't
+ * offline it. A node spans memory after move_pfn_range_to_zone(),
+ * e.g., after the memory block was onlined.
+ */
+ if (node_spanned_pages(nid))
+ return;
+
+ /*
+ * Especially offline memory blocks might not be spanned by the
+ * node. They will get spanned by the node once they get onlined.
+ * However, they link to the node in sysfs and can get onlined later.
+ */
+ rc = for_each_memory_block(&nid, check_no_memblock_for_node_cb);
+ if (rc)
+ return;
+
+ if (check_cpu_on_node(nid))
+ return;
+
+ /*
+ * all memory/cpu of this node are removed, we can offline this
+ * node now.
+ */
+ node_set_offline(nid);
+ unregister_one_node(nid);
+}
+EXPORT_SYMBOL(try_offline_node);
+
+static int __ref try_remove_memory(u64 start, u64 size)
+{
+ struct memory_block *mem;
+ int rc = 0, nid = NUMA_NO_NODE;
+ struct vmem_altmap *altmap = NULL;
+
+ BUG_ON(check_hotplug_memory_range(start, size));
+
+ /*
+ * All memory blocks must be offlined before removing memory. Check
+ * whether all memory blocks in question are offline and return error
+ * if this is not the case.
+ *
+ * While at it, determine the nid. Note that if we'd have mixed nodes,
+ * we'd only try to offline the last determined one -- which is good
+ * enough for the cases we care about.
+ */
+ rc = walk_memory_blocks(start, size, &nid, check_memblock_offlined_cb);
+ if (rc)
+ return rc;
+
+ /*
+ * We only support removing memory added with MHP_MEMMAP_ON_MEMORY in
+ * the same granularity it was added - a single memory block.
+ */
+ if (mhp_memmap_on_memory()) {
+ rc = walk_memory_blocks(start, size, &mem, test_has_altmap_cb);
+ if (rc) {
+ if (size != memory_block_size_bytes()) {
+ pr_warn("Refuse to remove %#llx - %#llx,"
+ "wrong granularity\n",
+ start, start + size);
+ return -EINVAL;
+ }
+ altmap = mem->altmap;
+ /*
+ * Mark altmap NULL so that we can add a debug
+ * check on memblock free.
+ */
+ mem->altmap = NULL;
+ }
+ }
+
+ /* remove memmap entry */
+ firmware_map_remove(start, start + size, "System RAM");
+
+ /*
+ * Memory block device removal under the device_hotplug_lock is
+ * a barrier against racing online attempts.
+ */
+ remove_memory_block_devices(start, size);
+
+ mem_hotplug_begin();
+
+ arch_remove_memory(start, size, altmap);
+
+ /* Verify that all vmemmap pages have actually been freed. */
+ if (altmap) {
+ WARN(altmap->alloc, "Altmap not fully unmapped");
+ kfree(altmap);
+ }
+
+ if (IS_ENABLED(CONFIG_ARCH_KEEP_MEMBLOCK)) {
+ memblock_phys_free(start, size);
+ memblock_remove(start, size);
+ }
+
+ release_mem_region_adjustable(start, size);
+
+ if (nid != NUMA_NO_NODE)
+ try_offline_node(nid);
+
+ mem_hotplug_done();
+ return 0;
+}
+
+/**
+ * __remove_memory - Remove memory if every memory block is offline
+ * @start: physical address of the region to remove
+ * @size: size of the region to remove
+ *
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations before this call, as required by
+ * try_offline_node().
+ */
+void __remove_memory(u64 start, u64 size)
+{
+
+ /*
+ * trigger BUG() if some memory is not offlined prior to calling this
+ * function
+ */
+ if (try_remove_memory(start, size))
+ BUG();
+}
+
+/*
+ * Remove memory if every memory block is offline, otherwise return -EBUSY is
+ * some memory is not offline
+ */
+int remove_memory(u64 start, u64 size)
+{
+ int rc;
+
+ lock_device_hotplug();
+ rc = try_remove_memory(start, size);
+ unlock_device_hotplug();
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(remove_memory);
+
+static int try_offline_memory_block(struct memory_block *mem, void *arg)
+{
+ uint8_t online_type = MMOP_ONLINE_KERNEL;
+ uint8_t **online_types = arg;
+ struct page *page;
+ int rc;
+
+ /*
+ * Sense the online_type via the zone of the memory block. Offlining
+ * with multiple zones within one memory block will be rejected
+ * by offlining code ... so we don't care about that.
+ */
+ page = pfn_to_online_page(section_nr_to_pfn(mem->start_section_nr));
+ if (page && zone_idx(page_zone(page)) == ZONE_MOVABLE)
+ online_type = MMOP_ONLINE_MOVABLE;
+
+ rc = device_offline(&mem->dev);
+ /*
+ * Default is MMOP_OFFLINE - change it only if offlining succeeded,
+ * so try_reonline_memory_block() can do the right thing.
+ */
+ if (!rc)
+ **online_types = online_type;
+
+ (*online_types)++;
+ /* Ignore if already offline. */
+ return rc < 0 ? rc : 0;
+}
+
+static int try_reonline_memory_block(struct memory_block *mem, void *arg)
+{
+ uint8_t **online_types = arg;
+ int rc;
+
+ if (**online_types != MMOP_OFFLINE) {
+ mem->online_type = **online_types;
+ rc = device_online(&mem->dev);
+ if (rc < 0)
+ pr_warn("%s: Failed to re-online memory: %d",
+ __func__, rc);
+ }
+
+ /* Continue processing all remaining memory blocks. */
+ (*online_types)++;
+ return 0;
+}
+
+/*
+ * Try to offline and remove memory. Might take a long time to finish in case
+ * memory is still in use. Primarily useful for memory devices that logically
+ * unplugged all memory (so it's no longer in use) and want to offline + remove
+ * that memory.
+ */
+int offline_and_remove_memory(u64 start, u64 size)
+{
+ const unsigned long mb_count = size / memory_block_size_bytes();
+ uint8_t *online_types, *tmp;
+ int rc;
+
+ if (!IS_ALIGNED(start, memory_block_size_bytes()) ||
+ !IS_ALIGNED(size, memory_block_size_bytes()) || !size)
+ return -EINVAL;
+
+ /*
+ * We'll remember the old online type of each memory block, so we can
+ * try to revert whatever we did when offlining one memory block fails
+ * after offlining some others succeeded.
+ */
+ online_types = kmalloc_array(mb_count, sizeof(*online_types),
+ GFP_KERNEL);
+ if (!online_types)
+ return -ENOMEM;
+ /*
+ * Initialize all states to MMOP_OFFLINE, so when we abort processing in
+ * try_offline_memory_block(), we'll skip all unprocessed blocks in
+ * try_reonline_memory_block().
+ */
+ memset(online_types, MMOP_OFFLINE, mb_count);
+
+ lock_device_hotplug();
+
+ tmp = online_types;
+ rc = walk_memory_blocks(start, size, &tmp, try_offline_memory_block);
+
+ /*
+ * In case we succeeded to offline all memory, remove it.
+ * This cannot fail as it cannot get onlined in the meantime.
+ */
+ if (!rc) {
+ rc = try_remove_memory(start, size);
+ if (rc)
+ pr_err("%s: Failed to remove memory: %d", __func__, rc);
+ }
+
+ /*
+ * Rollback what we did. While memory onlining might theoretically fail
+ * (nacked by a notifier), it barely ever happens.
+ */
+ if (rc) {
+ tmp = online_types;
+ walk_memory_blocks(start, size, &tmp,
+ try_reonline_memory_block);
+ }
+ unlock_device_hotplug();
+
+ kfree(online_types);
+ return rc;
+}
+EXPORT_SYMBOL_GPL(offline_and_remove_memory);
+#endif /* CONFIG_MEMORY_HOTREMOVE */
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-22 07:54:50 +0000