blob: a444e2d7dd2bffa3ffe496830a76395f21e7767e [file] [log] [blame]
// 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_PAGE_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_PAGE_ORDER-aligned, Set order to MAX_PAGE_ORDER for
* the case.
*/
if (pfn)
order = min_t(int, MAX_PAGE_ORDER, __ffs(pfn));
else
order = MAX_PAGE_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, bool mhp_off_inaccessible)
{
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;
/*
* Memory block is accessible at this stage and hence poison the struct
* pages now. If the memory block is accessible during memory hotplug
* addition phase, then page poisining is already performed in
* sparse_add_section().
*/
if (mhp_off_inaccessible)
page_init_poison(pfn_to_page(pfn), sizeof(struct page) * nr_pages);
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
bool mhp_supports_memmap_on_memory(void)
{
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) 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)
*
* b) 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())
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);
}
EXPORT_SYMBOL_GPL(mhp_supports_memmap_on_memory);
static void __ref remove_memory_blocks_and_altmaps(u64 start, u64 size)
{
unsigned long memblock_size = memory_block_size_bytes();
u64 cur_start;
/*
* For memmap_on_memory, the altmaps were added on a per-memblock
* basis; we have to process each individual memory block.
*/
for (cur_start = start; cur_start < start + size;
cur_start += memblock_size) {
struct vmem_altmap *altmap = NULL;
struct memory_block *mem;
mem = find_memory_block(pfn_to_section_nr(PFN_DOWN(cur_start)));
if (WARN_ON_ONCE(!mem))
continue;
altmap = mem->altmap;
mem->altmap = NULL;
remove_memory_block_devices(cur_start, memblock_size);
arch_remove_memory(cur_start, memblock_size, altmap);
/* Verify that all vmemmap pages have actually been freed. */
WARN(altmap->alloc, "Altmap not fully unmapped");
kfree(altmap);
}
}
static int create_altmaps_and_memory_blocks(int nid, struct memory_group *group,
u64 start, u64 size, mhp_t mhp_flags)
{
unsigned long memblock_size = memory_block_size_bytes();
u64 cur_start;
int ret;
for (cur_start = start; cur_start < start + size;
cur_start += memblock_size) {
struct mhp_params params = { .pgprot =
pgprot_mhp(PAGE_KERNEL) };
struct vmem_altmap mhp_altmap = {
.base_pfn = PHYS_PFN(cur_start),
.end_pfn = PHYS_PFN(cur_start + memblock_size - 1),
};
mhp_altmap.free = memory_block_memmap_on_memory_pages();
if (mhp_flags & MHP_OFFLINE_INACCESSIBLE)
mhp_altmap.inaccessible = true;
params.altmap = kmemdup(&mhp_altmap, sizeof(struct vmem_altmap),
GFP_KERNEL);
if (!params.altmap) {
ret = -ENOMEM;
goto out;
}
/* call arch's memory hotadd */
ret = arch_add_memory(nid, cur_start, memblock_size, &params);
if (ret < 0) {
kfree(params.altmap);
goto out;
}
/* create memory block devices after memory was added */
ret = create_memory_block_devices(cur_start, memblock_size,
params.altmap, group);
if (ret) {
arch_remove_memory(cur_start, memblock_size, NULL);
kfree(params.altmap);
goto out;
}
}
return 0;
out:
if (ret && cur_start != start)
remove_memory_blocks_and_altmaps(start, cur_start - start);
return ret;
}
/*
* 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 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) &&
mhp_supports_memmap_on_memory()) {
ret = create_altmaps_and_memory_blocks(nid, group, start, size, mhp_flags);
if (ret)
goto error;
} else {
ret = arch_add_memory(nid, start, size, &params);
if (ret < 0)
goto error;
/* create memory block devices after memory was added */
ret = create_memory_block_devices(start, size, NULL, group);
if (ret) {
arch_remove_memory(start, size, params.altmap);
goto error;
}
}
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:
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();
/*
* Make sure to mark the node as memory-less before rebuilding the zone
* list. Otherwise this node would still appear in the fallback lists.
*/
node_states_clear_node(node, &arg);
if (!populated_zone(zone)) {
zone_pcp_reset(zone);
build_all_zonelists(NULL);
}
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 count_memory_range_altmaps_cb(struct memory_block *mem, void *arg)
{
u64 *num_altmaps = (u64 *)arg;
if (mem->altmap)
*num_altmaps += 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 memory_blocks_have_altmaps(u64 start, u64 size)
{
u64 num_memblocks = size / memory_block_size_bytes();
u64 num_altmaps = 0;
if (!mhp_memmap_on_memory())
return 0;
walk_memory_blocks(start, size, &num_altmaps,
count_memory_range_altmaps_cb);
if (num_altmaps == 0)
return 0;
if (WARN_ON_ONCE(num_memblocks != num_altmaps))
return -EINVAL;
return 1;
}
static int __ref try_remove_memory(u64 start, u64 size)
{
int rc, nid = NUMA_NO_NODE;
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;
/* remove memmap entry */
firmware_map_remove(start, start + size, "System RAM");
mem_hotplug_begin();
rc = memory_blocks_have_altmaps(start, size);
if (rc < 0) {
mem_hotplug_done();
return rc;
} else if (!rc) {
/*
* Memory block device removal under the device_hotplug_lock is
* a barrier against racing online attempts.
* No altmaps present, do the removal directly
*/
remove_memory_block_devices(start, size);
arch_remove_memory(start, size, NULL);
} else {
/* all memblocks in the range have altmaps */
remove_memory_blocks_and_altmaps(start, size);
}
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 */